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Final Answers
© 2000-2017   Gérard P. Michon, Ph.D.

Nikon DX Photography
To the memory of Gilles Galerne (1953-2012)
founder of  K 5600  Lighting

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Related articles on this site:

Related Links (Outside this Site)

DxOMark:  Camera & lens independent image-quality measurements.
Cambridge in Colour  "A Learning Community for Photographers".
Nikon Hacker  "Dedicated to the improvement of DSLRs".
Nikon Passion  "Passionnés de photographie et de matériel photo".
Nikon Service Manuals and Brochures for older cameras  (unofficial).
Through the F-Mount  by  Jürgen Becker.  [Tubes & TC]
Recommended lenses for DX users  by  Thom Hogan  (2016).
Nikon :   Nikon Canada   |   Nikon USA

Introduction :  Nikon D3300 & D5300, kit lenses, AF, GPS, Wi-fi  (13:07)  by
Tony & Chelsea Northrup  (2014).   Authors of  Stunning Digital Photography.

 Nikon D5500

Nikon D5500   (released February 5, 2015)

The D5500 is the successor of the D5300 released in 2013  (another numbering might have invited confusion with the popular "Nikon 5400"; which is how the  Coolpix 5400  came to be known, back in 2003).  Predecessor of the D5600.

Wikipedia  |  Specs  |  DP Review  |  Official site  |  Download center
Accessories :   IkeLite Underwater Housing for Nikon D5500

D5500  Videos :

D5500 / D5300 / D5200  Focusing  (10:06)  Michael The Maven  (2014-03-12).
Nikon D5500:  Product Tour  (2:07)  by  Nikon Asia  (2015-01-05).
Introducing the Nikon D5500 HD-SLR  (4:18)  by  Paul Reid  (2015-01-05).
Nikon D5500 Preview  (8:36)  by  Jared Polin  (2015-01-05).
Nikon D5500, CES Editors' Choice winner  (2:12)  USA Today  (2015-01-07).
D5500 Preview  (25:18)  by  Tony Northrup  (2015-01-07).
Nikon D5500 Hands-on, CES 2015  (2:44)  by  Jared Polin  (2015-01-09).
Nikon D5500: Antarctica Wildlife  (36:26)  by  James Pickard  (2015-01-21).
Nikon D5500: A Journey of Mind's Peace  (3:59)  by  IIMA  (2015-02-03).
Nikon D5500 DSLR Unboxing  (8:05)  by  Slanted Pillow  (2015-02-10).
Nikon D5500 Hands-On Field Test  (11:07)  by  Chris Niccolls  (2015-02-12).
D5500 Overview Training Tutorial  (56:00)  Tony Northrup  (2015-02-15).
Nikon D5500 hands-on review  (4:02)  Ben Shaul  (2015-02-17).
Nikon D5500 Review vs. D5300, T5i  (23:44)  Toby Gelston  (2015-02-24).
Nikon D5500 Big Review  (4:07)  by  Amy Davis  (2015-03-03).
BEST Entry Level DSLR of 2015  (4:41)  by  Karl Conrad  (2015-03-05).
Nikon D5500 Hands-on Review  (6:21)  by  Kai Wong  (2015-03-13).
Nikon D5500 - Review (English)  (38:23)  by  Ralfs Foto-Bude  (2015-03-13).
Nikon D5500 Review  (26:40)  by  Corey Benoit  (2015-03-18).
Hands-On Review: Nikon D5500  (12:42)  by  Larry Becker  (2015-03-23).
Nikon D5500 review  (8:14)  by  Ivan Ivancic  (2015-03-24).
Nikon D5500 (18-140mm) 5 Min Portrait  (1:01:48)  J. Polin  (2015-04-02).
Nikon D5500 User's Guide  (47:01)  by  Jared Polin  (2015-04-18).
Nikon D5500 Unboxing & Initial Impressions  (7:35)  Matt Ballard  (2015-04-30).
D5500 Video Shooting Review  (47:01)   Nice Lady  (2015-05-09).  [sample]
Nikon D5500 unboxing and review  (35:20)  Craig's Reviews  (2015-06-09).
Nikon D5500 unboxing, review & samples  (15:23)  Nothing Wired  (2015-07-10).
Nikon D5500 Review  (16:59)  LensVid Exclusive  (2015-11-30).
In-depth review of the Nikon D5500  (33:08)  TheTechGuy600  (2016-02-01).
Tutorial | D5500 | Most Asked Questions  (1:00:15)  DigitalGoja  (2016-05-14).
Nikon D5500 Real Review 2016  (8:20)  Milton Stone  (2016-05-16).
D5500 real-world hands-on review  (11:33)  by  Maarten Heilbron  (2016-07-11).
The Great JPEG Shootout: D5500 wins! (21:15)  The Camera Store  (2016-11-15).

 Nikon D500 with 200-500mm zoom

Nikon D500   (released January 6, 2016)

The acclaimed D500 is the long-awaited successor to the D300 & D300s (2007, 2009)  at the top of Nikon's DX lineup.

Wikipedia  |  Specs  |  DP Review  |  Official site  |  Download center

D500  Videos :

D500 hands on - Best APS-C camera?  (7:33)  by  Matt Granger  (2016-01-05).
Nikon D500 Preview  (5:10)  by  Jared Polin  (2016-01-05).
Nikon D500 Preview  (23:11)  by  Tony Northrup  (2016-01-06).
Nikon D500: First Impressions  (5:43)  by  Brittany Leigh  (2016-01-06).
Nikon D500: Second Impressions  (4:01)  by  Brittany Leigh  (2016-01-12).
D500 - DX Flagship Dismissed as a Joke  (16;08)  by  Toby Gelston  (2016-01-24).
Nikon D500 - King of Crop?  (7:00)  by  Sean Michael  (2016-01-25).
Nikon D500 Un-Boxing  (8:47)  by  Jared Polin  (2016-04-21).
Nikon D500 Reviewed... New Legend  (12:22)  by  Ken Wheeler  (2016-04-22).
What's the  place  of the D500 Nikon?  (7:24)  by  Ken Wheeler  (2016-04-24).
First Look at the Nikon D500  (14:23)  by  Nancy Elwood  (2016-04-24).
The Nikon D500 Soap Opera + outtakes  (7:15)  by  Brittany Leigh  (2016-04-26).
The soon-to-be legendary Nikon D500  (8:05)  by  Ken Wheeler  (2016-05-05).
Nikon D500 Hands-On Field Test  (18:09)  Chris Niccolls  (2016-05-07).
[ Controls  |  Focus ]  D500 tutorials  by  Michael The Maven  (2016-05-11 / 22).
What the Nikon D500 can do others  can't  (6:16)  by  Ken Wheeler  (2016-05-13).
Nikon D500 AF calibration tutorial  (4:51)  by  Dave Flynn  (2016-05-16).
Nikon D500 - SnapChick Review  (17:14)  by  Brittany Leigh  (2016-05-21).
Nikon D500 Hands-on Review  (11:10)  by  Kai Man Wong  (2016-05-21).
Nikon D500 Body Tour  (10:51)  by  Brittany Leigh  (2016-05-26).
Nikon D500 - Beyond the Review  (15:20)  by  Brittany Leigh  (2016-05-28).
Nikon D500: Best  High-ISO cropped sensor  (24:00)  Jared Polin  (2016-05-28).
Nikon D500 Review  (1:05:52)  This week in Photo  (2016-05-30).
D500: A Wildlife Photographer's Perspective  (25:26)  Steve Perry  (2016-06-01).
D500: Best all-around DSLR on the market  (30:13)  Jared Polin  (2016-06-02).
In Chappell Hill, TX, with the D5 and D500  (13:39)  Sara Strick  (2016-06-03).
How to set up your new Nikon D500  (33:41)  Jared Polin  (2016-06-04).
Nikon D500 Menus Overview  (5:49)  by  Brittany Leigh  (2016-06-08).
Nikon D500 - Field Tested Review  (19:50)  by  Matt Granger  (2016-06-12).
[ Backbutton Focus  |  Tips & Tricks ]   by  Ken Wheeler  (2016-06-12 / 13).
Nikon D500 vs. D7200 - Head to Head  (6:50)  by  Chris Winter  (2016-06-20).
Who is the Nikon D500 for?  (2:59)  by  Jakub Wojtkiewicz  (2016-06-24).
Nikon D500 Advanced Guide  (29:00)  by  Matt Granger  (2016-06-25).
Nikon D500 vs. D750, for Weddings  (10:30)  by  Taylor Jackson  (2016-06-25).
Nikon D500 vs. Nikon D750  (7:34)  by  Jared Polin  (2016-06-28).
Nikon D500 vs. Canon 7D Mark II  (10:09)  by  Kai Man Wong  (2016-07-03).
Nikon D500 In-Depth Review  (12:14)  by  Deon Joubert  (2016-07-08).
Nikon D500 vs. D750 Hands-on Comparison  (10:36)  Kai & Paul  (2016-07-09).
Nikon D500: The Best DSLR of 2016?  (18:28)  by  Eric Rossi  (2016-08-05).
Nikon D500: First impressions  (12:32)  by  Peter Gregg  (2016-08-14).
Outdoor Summit, Switzerland  (7:05)  Eder & Carlier, by Frutiger  (2016-08-16).
Nikon D500 Overview Tutorial  (1:11:11)  by  Tony Northrup  (2016-08-20).
Nikon D500 Review  (32:18)  by  Corey Benoit  (2016-08-25)
Test & Review of the Nikon D500 - in 4K  (25:15)  Zed Promedia  (2016-09-07).
Detailed hands-on test, in Paris - 4K  (21:43)  Maarten Heilbron  (2016-09-21).
Nikon D500 - Field Test and Review  (28:12)  RealWorld  (2016-10-13).
Birds in Flight,  with Ronan Donovan  (10:37)  DP Review  (2016-10-17).
Nikon D500 DSLR Camera | FAQ Video  (24:14)  Digital Goja  (2016-11-03).
Unboxing My Dream Camera - Nikon D500  (11:44)  EK  (2016-11-05).
Nikon D500 Pros & Cons  (7:43)  LensVid  (2016-11-14).
Nikon D500 - The Moment of Impact  (1:30)  by  Tom Miles   (2016-11-17).
Fuji X-T2 vs. Nikon D500  (30:27)  by  Michael The Maven  (2016-11-22).
Nikon D500 & D5:  4K UHD Compilation  (2:00)  Fan of Tech  (2016-12-16).
Nikon D500 & 35mm f/1.8G for a week  (10:27)  Brittany Leigh  (2016-12-20).
Nikon 500mm f4 G VR Unboxing   D500  (10:41)  EK  (2016-12-22).
D500 Review  (4:16)  by  Chris Balmer,  Perfect Light Store  (2016-12-28).
The best cameras of 2016:  D500 & XT-2  (13:34)  Zed ProMedia  (2016-12-31).
Nikon D500: Updated Review  (10:57)  by  Brittany Leigh  (2017-01-20).
D500 & X-T2:  Future-proof cameras  (8:51)  by  Ken Wheeler  (2017-01-21).
D500 resurrection,  0 | 1 | 2 | 3 | 4 | 5 | 6  by  Ken Wheeler  (2017-01-31).
AA batteries with D500 vertical grip  (5:41)  by  Ken Wheeler  (2017-02-11).


Nikon  DX  Photography
Technical Review of a Full System:  Camera, Lenses, Accessories...

Camera manufacturers use different names for the same feature.  Here are the abbreviations used by Nikon and the names prevalent in the Nikon Universe :

FX Full-frame (FF).  Designed for an image sensor of 24mm by 36mm
DX Designed for an AP-C format  sensor,  roughly  24mm by 16mm.
VR Vibration Reduction.  A mechanical system compensates for lateral shakes, making slower shutter speeds practical.
SWM Silent Wave Motor.  Lens uses a piezo motor for autofocusing.
OLPF Optical low-pass filter.  Anti-aliasing (AA) filter, in front of the sensor.
AFP Auto Focal-Plane.  Speedlight acting as a fast stroboscope for more than  1/200 s  allows uniform illumination ar faster shutter speeds.

(2017-02-18)   Ancestry of Current Nikon DX Cameras
Transition from film to digital cameras.

 Come back later, we're
 still working on this one...

Nikon D40 :   Wikipedia   |   Ken Rockwell   (2006-2010)   |   Nikon Archives

(2015-05-22, 2017-01-09)   4 lines of Nikon crop-sensor DSLR bodies :
Buyer's Guide  (and Editor's Choices)  for Nikon DX cameras.

Many professionals tend to prefer the "full-frame" FX format  (inherited from the bygone era of  35 mm film).  However, the "crop sensor" DX format can be superior in some domains, like wildlife photography and macro-photography.  (Wedding photography isn't one of those.)

New DX lenses cost typically two or three times less than their FX counterparts, which is an important consideration for those of us who don't earn a living using photographic gear...

Nikon currently offers four series of DSLR cameras in DX format:

  • Entry level  (D3000 series).
  • Mid-level  (D5000 series).
  • Semi-pro  (D7000 series).
  • Professional  (D500, formerly D300 and D300s).

The last two qualify as "professional" because of a rugged metal construction and weather-sealing which the other two lack.  Also, they offer an additional LCD screen on top of the camera to show its settings and two  separate  wheels for shutter and aperture control  (in amateur cameras, both functions are controlled by the same wheel; pressing a button makes the wheel control aperture instead of shutter speed).  Professionals value such time savers but amateurs don't mind the extra time and effort.

The rest of this webpage singles out the  D5500  as the best value for most amateurs in 2016  (unless they have a collection of motor-less lenses).  Also, the D5500 has better video capabilities than the D7200.  With the money you save by buying a D5500 instead of a D7200, you can get a  nice  fast prime lens,  a good  third party flash unit  and a  tripod...

Most cameras listed here produce the same great picture quality, using a 24-megapixel sensor with no optical low-pass filter  (older versions thereof are used on the D3300 and D5300).  The D500 sports an entirely different type of sensor,  rated 20.9 megapixels and better suited to low-light conditions.

Two features are  missing  (not just less accessible)  on the D5500:

  • The arcane  (but occasionally indispensable)  ability to operate compatible speedlights in AFP mode  (HSS).
  • Direct white-balance input in terms of the  color temperature  of the light source, in kelvins (K).

Both features could be supplied by Nikon in a future D5500 firmware upgrade, if they choose to do so.  They are available on the  D7200,  but the D7200 is still lagging in the video department.

For many years, an important gripe about  all  Nikon DX cameras had been their inability to change the aperture in liveview or when shooting video  (because the aperture control is mechanical).  The issue is fixed on the D500.

Nikon's lineup of some recent DX cameras  (2015-2016)
Model D3300 D5300 D5500 D7200
Released  (month) 2014-01 2013-10 2015-02 2015-03
Current price  (body only) $324 $647 $747 $997
Working body weight (no cap) 460 g 530 g 470 g 765 g
Pop-up Flash yes yes yes yes
Metal body, weather-sealed no no no yes
Works with motorless lenses no no no yes
Best color depth 12 bits 14 bits 14 bits 14 bits
Shooting rate / buffer size 5 fps /11 5 fps /6 5 fps /6 6 fps /18
Autofocus points / cross-type 11 / 1 39 / 9 39 / 9 51 / 15
Autofocus aperture limit 1:5.6 1:5.6 1:5.6 1:8
Metering pixels 420 2016 2016 2016
Exposure bracketing no yes yes yes
Orientable screen no yes yes no
Touch-screen no no yes no
Eye-sensor  (proximity switch) no no yes no
Built-in Wi-Fi no yes yes yes
Built-in GPS no yes no no
Top shutter speed 1/4000 s 1/4000 s 1/4000 s 1/8000 s
X  flash synchronization 1/200 s 1/200 s 1/200 s 1/250 s
AFP  (HSS)  flash mode no no no yes
Easy-panorama yes no no no
Flat profile (video) no no yes yes
Top rate in full HD (1080 p) 60 fps 60 fps 60 fps 60 fps
Custom white balance 1116
Change aperture in liveview no no no no

This last point compares unfavorably to Canon cameras of the same class.  On  all  DX Nikon cameras before the D500,  the aperture selected when you enter liveview or start shooting video cannot be changed until you're done.  In Liveview, what you see is actually shot with that aperture.  This gives you a depth-of-field preview but may darken the field and hinder autofocus.  If that's a concern, you may enter liveview at full aperture and select a different aperture for the next still shot.  That would be fine and dandy, except that the new darker aperture automatically becomes selected for liveview once that shot is taken  (to return to the previous situation, you must exit liveview and open the aperture manually before returning to liveview).  Inconvenient as it may be for shooting stills, the same design flaw prevents you from changing the aperture at all during the recording of a video.  Bad.

I've had no problems autofocusing an extended  telephoto zoom  at  1:6.3  with a  Nikon D5500  (that's beyond what the manufacturer guarantees).

Nikon says that the guide number of the built-in flash of the above cameras is  12 m = 39 ft  at ISO 100 / 21°.  (At least, that's what they meant to say.)

 Blunder Blunder Alert :  Bizarrely,  Nikon writers  misinterpreted  as a temperature the latter part of that  legacy specification  of  ISO 100  (formerly known as  ASA 100  or  DIN 21°).  They went one more step in the wrong direction and thought that  21° was close enough to  standard room temperature  (293 K)  which is often quoted as  20°C/68°F  (see Celsius and Fahrenheit).  So, they just replaced the former by the latter all over the place, mindlessly!  This now stands, throughout Nikon specs, as an embarrassing monument to the scientific illiteracy of marketing folks.

The URL of this rant is www.numericana.com/answer/nikon.htm#blunder
Please, tell me if/when this has been fixed so I can have the joy of removing this derogatory comment ASAP.  I love Nikon and I weep when they put themselves in an embarrassing spot.

The current models of Nikon DX cameras  (2017 update)
Model D3400 D5600 D7200 D500
Released  (month) 2016-08 2016-09 2015-02 2016-01
Current price  (body only) $350 $697 $997 $1997
Working body weight (no cap) 445 g 465 g 765 g 860 g
Pop-up Flash yes yes yes no
Works with motorless lenses no no yes yes
Metal body, weather-sealed no no yes yes
Best color depth 12 bits 14 bits 14 bits 14 bits
Shooting rate / buffer size 5 fps /11 5 fps /6 6 fps /18 10 fps
Autofocus points / cross-type 11 / 1 39 / 9 51 / 15 153 / 99
Autofocus aperture limit 1:5.6 1:5.6 1:8 1:8
Metering pixels 420 2016 2016 180 k
Exposure bracketing no yes yes yes
Orientable screen no yes no Tilt
Touch-screen no yes no yes
Eye-sensor  (proximity switch) no yes no
Built-in Wi-Fi no yes yes yes
Top shutter speed 1/4000 s 1/4000 s 1/8000 s 1/8000 s
X  flash synchronization 1/200 s 1/200 s 1/250 s 1/250 s
AFP  (HSS)  flash mode no no yes yes
Flat profile (video) no yes yes yes
Top rate in full HD (1080 p) 60 fps 60 fps 60 fps 60 fps
4 K UHD video (3840 by 2160 p) no no no yes
Custom white balance 1166
Change aperture in liveview no no no yes
Depth-of-field preview no no no yes
Radio-control of flash units no no no yes

The Nikon D500 Breakthrough :

The D500 is the first Nikon DX camera which allows changing the aperture in liveview and/or video mode  (see above gripe).  The D500 also introduces  Auto AF Fine Tune,  which can adjust AF Fine Tune settings for the attached lens,  when focus is achieved in  liveview.  It memorizes up to 20 lenses.

The D500 has the same autofocusing system as the D5  (Nikon's newest full-frame camera)  and lacks a focusing lamp  (presumably because it doesn't need one).  The D500 can shoot state-of-the-art  4 K UHD  video  (3840 by 2160 pixels)  albeit at an  overall crop factor of 2.33.

Foregoing a pop-up flash for better weather-proofing and trading  sensor resolution  for best low-light performance has made the  D500  truly stellar.

(2015-05-30)   Frames per Second   (fps)
The  D5500  can shoot at a top rate of  exactly  5 fps.

There are countless videos on YouTube of reviewers who "test" the continuous-shooting capabilities of new cameras by bringing the camera lovingly to their cheek  (the way James Bond does with his gun)  before taking many out-of-focus pictures of the ceiling...

The result of that is invariably that the camera starts at a rapid rate and then slows down dramatically after a few shots.  Often, the reviewer will conclude that it takes so many shots to overrun the camera's buffer, as the true rate of continuous transfer to the memory card is indicated by the sluggish rate in the second part of the test.  That's true.  Kinda.

 RadioShack Stopwatch  Let's make things a little bit more scientific by taking pictures of the main measuring instrument itself  (a cheap LCD stopwatch).  The D5500 does take 100 pictures of the stopwatch in 20 seconds... 

Using the continuous video lights of an SB-500 to illuminate the running stopwatch, the D5500 was set to manual mode and manual focus  (shutter at  1/200 s).  In high-rate continuous mode the camera took  exactly  one shot every  200 ms  (it never went out of sync with the stopwatch).  The camera stopped by itself after those 100 shots because, like many cameras, the D5500 is designed not to take more than 100 pictures at once  (after briefly lifting my finger from the release button, I was able to start another sequence immediately).  So, the modest "6-picture" buffer  never  fills up!  What's the deal?

Well, I was just shooting "JPEG-normal" which, according to the camera itself, corresponds to  8.6 MB  per  picture  (using the best resolution of 6000 by 4000).  When shooting 14-bit RAW instead  (37 MB  per frame)  I got only a burst of 6 pictures  200 ms  apart  (that's what 5 fps means).  Then, the rate dropped down to  800 ms  per frame  (or, equivalently, 1.25 fps).  That's obviously the way Nikon rated their own camera, which is fair.

When shooting in JPEG-fine  (17 MB per frame)  I got 25 pictures in 5 seconds, at the top rate of 5 fps.  Then, the rate dropped to a steady  3.75 fps  in the long run...  Let's summarize:

Continuous-shooting capacity of the Nikon D5500
6000 x 4000
per shot
Rapid shots
@  5.00 fps
data rate
14-bit RAW37 MB61.25 fps46.25 MB/s
JPEG-fine17 MB253.75 fps63.75 MB/s
JPEG-normal8.6 MB1005.00 fps yes
Tests conducted with a fast  32 GB  memory card  ($15)  rated by the manufacturer at   90 MB/s.

(2015-05-18, 2017-01-21)   CCD Image Sensor
A close look at the sensors used in Nikon's latest DX cameras.

The sensor used in the D5500 and the D7200 has the same dimensions as the sensors of all  current DX models,  except the D500  (discussed later).

It's advertised as measuring 23.5 mm by 15.6 mm.  These are clearly rounded values, because their ratio isn't exactly  3/2.  For lack of better data from the manufacturer,  we'll use consistently the only pair of  4-digit  values in a ratio of  3/2  which are properly rounded to the above, namely:

23.46 mm     by     15.64 mm

The same result would be obtained by considering that a diagonal of  28.2 mm  (used to compute the angular field-of-view of a DX lens as a function of its focal length)  corresponds to 23.4638... by 15.6425...

Thus, the native resolution of 6000 by 4000 corresponds  exactly  to a square pixel of  3.91 microns.  It's 1/1000 the pitch of stadium LED displays  (a pitch of  exactly  3.90625  corresponds to 256 pixels per unit; a unit being  250 mm  for the LED displays and  0.25 mm  for the sensors).

A pitch of  3.9025 microns  would correspond to a sensor size of exactly:

23.4375 mm     by     15.625 mm

Such a sensor would have a  crop factor  of   24 / 15.625  =  1.536  exactly.

However,  there are some  clues  that the designers of Japanese sensors use nominal dimensions expressible exactly in hundredth of millimeters  (a manufacturing tradition in the West as well).  I am thus confident that this specification isn't currently in use  (and probably never will).

The value of  3.92 mm,  which is floating around,  isn't compelling either.  (It's the rounded-up value of 23.5/6000, but 15.6/4000 is exactly 3.9.)  However, that would correspond to a sensor size of  15.68mm  by  23.52mm,  which can be truncated (instead of rounded) to the dimensions quoted by the manufacturer  (and a crop factor of 1.5306).  No engineer worthy of the name would ever truncate a value rather than round it to the nearest digit,  but corporate personnel are not always engineers  (and they do blunder in worse ways).

The sensor is widely advertised as  "24.2 effective megapixels".  It has a total of 24.78 million pixels.  Its total surface area is about 367 mm (rounded from 366.9144 using the above precise dimensions).

The precise  crop factor  of the D5500 is thus:

36 / 23.46  =  24 / 15.64  =  3 / 1.955  =  1.5345...

Nikon uses  1.53  as the nominal DX crop factor.  The  "1.5"  approximation is a bit sloppy  (e.g., a  DX  300 mm  lens has the same  reach  as a  460 mm  lens on a 24x36mm camera,  not  450 mm).

Although the sensors on the D5500 and its immediate predecessor  (the D5300)  have exactly the same size, Nikon claims the chip has been entirely redesigned for better performance at high ISO.  Third-party tests seem to confirm this dramatically...

The Nikon D500 Sensor:

The published size of the  "20.9 Mp"  sensor is  23.5 x 15.7 mm.  With two decimal places,  only two sizes in a  3:2  ratio would be rounded to that, namely:  23.49 x 15.66  and  23.52 x 15.68.  We rule out the latter thusly:

The maximum image resolution of the  D500  is  5568 x 3712 pixels,  which is 3 x 2 multiplied into 64 times 29 pixels.  As 29 divides evenly 23.49 and 15.66,  we are led to retain the first of our two previous guesses as the nominal size intended by the sensor designers.  This corresponds to a pixel pitch of exactly  4.21875 microns per pixel,  advertised as 4.2 microns.  To summarize, the nominal sensor characteristics are:

5568 p  by  3712 p  (20668416 pixels)
23.49 mm  by  15.66 mm  nominal sensor size
Pixel size:  4.2 u   (4.21875 u/p  nominal pitch, exactly)
Crop factor :   24 / 15.66   =   4 / 2.61   =   1.5325670498...

When shooting video in  4K UHD  (3840 by 2160 p)  the  Nikon D500  retains only the central part of the sensor described above,  pixel for pixel.  The size of that central part is thus  exactly  16.2 mm  by  9.1125 mm  (16:9 aspect ratio).  The diagonal of that is about  18.587 mm,  correspondig to a nominal  crop ratio  of about  2.3277854.  Let's say 2.33.  (The values of  2.0  or  2.25,  given by some reviewers,  are misguided at best.)

Digital Camera Database:   D5500 | D500

(2015-05-14)   Enabling Back-Button Focus on the D5500
Decouple focusing from the shutter-release "front-button".

The only reason why auto-focusing is, by default, triggered when the front-button is pushed halfway is to force focusing to occur before every shot, even for first-time users...

A more flexible way is to assign a separate button to modify focusing on request only, so that you may recompose the picture without disturbing the established focus.  With default settings, that could be done by maintaining the front-button pressed half-way or pushing the "AE-L / AF-L" back-button, which locks both the acquired auto-exposure and auto-focus.  However, if the camera is not handheld, that's not an option  (think of night-photography using a tripod).  This is not an an option either in continuous-focusing mode.

To change the operating mode so that the back-button  (labeled AE-L/AF/K)  allows focusing when it's depressed and locks it when it's released, just reprogram your camera as follows:

  • Push the MENU button  (to the left of the viewfinder).
  • Select the pencil icon to bring up the "Custom Setting Menu".
  • Select f  "Controls",  then f2  "Assign AE-L/AF-L button".
  • Select the last option  ("AF ON")  to replace  "AE/AF lock".
  • Return to normal operation by pushing the MENU button.

If you choose back-button focus, you may want to consider assigning auto-exposure lock (AE-L) to the halfway front-button  (custom sub-menu c1).  This is not for everybody, but it gives you the ability to focus on one object, and meter light for an unrelated frame before composing the final shot!

In liveview mode, a new focusing point can always be selected by taping on the screen, regardless of the status of this back-button.

Other Suggested Custom Settings :

You may consider changing other default settings the same way as above.  For example, I find that the default of enabling an infrared remote  (ML-13)  for only one minute at a time can be frustrating.  Thus, I select the  "5 minutes"  option in the  c4  sub-menu.

How To Use AF-On And Back Button Autofocus  (10:25)  by  Steve Perry   (2014-01-03).
Back-button focusing with your DSLR  (12:52)  by  Bernie Raffe   (2014-05-12).
Back-Button Focus:  Why  everyone  should use it  (4:44)  by  Tony Northrup   (2014-08-11).
Back-Button Focus on Nikon Cameras  (8:14)  by  Mike Hagen   (2016-08-03).

(2015-05-18)   Commander mode using an SB-500 speedlight on a D5500
The SB-500 communicates with slaves using light pulses before a flash.

The only way the D5500 camera can communicate with external flash units is via its hot shoe.  It doesn't have a traditional  PC-sync  socket.

The built-in flash of the D5500 can't control remote units in "commander" mode.  To do that, you must put an SB-500 speedlight in the hot shoe.

Nikon's documentation for the 5500 camera only mentions the SB-500 for that rôle.  Some larger Nikon speedlights might work too.  What's clear is that the big units feel too heavy on top of the smallish D5500 camera, for which the SB-500 is a perfect match.  I'm not aware of any third-party unit which can replace the SB-500 as a commander.  The YN568EX discussed below works perfectly as a slave.

The D5500 supports only two groups of remote speedlights (zone A and B).  Both are independently controlled from the camera through the camera-mounted SB-500 speedlight.  This old-school system depends on light signals from the master unit just before each flash.  It has severe limitations:  All slave units must be placed no more than 30° from the forward direction of the commander.  The slaves can't be too far away and their receiving photocells must face the commander.

If you can spare a bit of money and a little room in your camera bag, it's far better to invest in a set of radio-controlled radio transceivers which provide radio-controlled hot shoes taking their commands from one central unit mounted on your camera.  Radio-control has none of the above restrictions.

Yongnuo YN568EX for Nikon :

Stay away from the related  YN568EX II,  which is designed for Canon.

The width of the beam can be set manually to  24, 28, 35, 50, 70, 85 or 105 mm, in that order, by pressing briefly the ZOOM button.  After that, it goes back to "auto"  (as indicated by the  lack  of an "M" circled in black on the LCD, before the aforementioned numerals)  which puts the head either to the  "35 mm"  setting or to whatever position is best suited for the lens currently mounted on the camera  (if the YN568EX is able to communicate with it via the hot shoe).

When the built-in diffuser of the YN568EX is pulled out, all of the above is overridden.  The LCD shows "(M) 14 mm" and the zoom head automatically retracts to its widest setting.

To make the YN568EX enter or leave its slave mode, you push the ZOOM button for a long time  (ignore what the printed manual may say about using the CH/GRP button for that purpose).  In the slave mode, the two large LEDs in the front of the unit keep flashing.  When the unit is mounted on the camera, it automatically leaves slave mode.

To communicate with the SB-500, the YN568EX must be programmed  (once and for all)  while it's in slave mode.  To do that, select "Channel 3"  (the only channel of the SB-500)  by pushing the CH/GRP button once and using the D-pad until a tiny "3" appear at the bottom of the LCD.  Press the  CH/GRP  button once more to select, with the D-pad, the group you intend to use  (A or B, since C isn't a valid choice on the D5500; the group setting of the SB-500 is irrelevant when it's used as a commander).  Press ZOOM when done.
The  CH/GRP  button stands for  "Channel / Group"  and alternates between the two types of selections just described  (or neither of them)  when the unit is in slave mode.  In normal mode, the CH/GRP button acts exactly like the ZOOM button, except that pressing it for a long time won't put you into slave mode, as remarked above  (in spite of what the printed manual may say).

No Auto-FP (HSS) :   Normally, a Nikon camera in commander mode should allow a remote unit capable of Auto-FP, like the YN568EX, to fire as such, whenever the shutter speed is faster than 1/200 s.  Apparently, the D5500 isn't able to do so in the commander mode enabled by mounting an SB-500 on it.  A second-class citizen, in that respect at least.

This is merely a problem with the firmware of the D5500  (whose built-in flash doesn't support AFP).  Arguably, the firmware should either make the following assumption by default, or at least provide a menu option to allow it to be made:  When the on-camera SB-500 is in commander mode and set not to fire itself, shutters speeds slower than  1/200 s  can be used because the remote units will provide AFP illumination  (it's the responsibility of the photographer to make sure they do).

 Nikon ML-L3 Infrared Remote
(2015-05-14)   Remote Control
Cable, infrared, wireless and Wi-Fi.

Nikon's ML-L3  (shown at right)  is a tiny single-button infrared remote-control unit.  The genuine Nikon model may cost  $20  or more.  However, for $5 or less, you can have nearly identical substitutes or multi-brand models.

If you're not afraid of microcontrollers, the technical information to make your own Nikon-compatible IR-remote is given  elsewhere on this site.  That may also be used to program a smartphone having an infrared link.

There are two infrared receivers on the  D5500  camera;  one in the front  (in the middle of the grip)  and one in the back  (to the left of the MENU button).  There are several ways to enable the infra-red link for a short amount of time  (the default duration of one minute can be changed to  5, 10 or 15 minutes,  using the  c4  sub-menu).  The quickest way is to press the "release mode" button  (in the front, below the big lens-lock button)  and rotate the dial to select either of the infrared release modes  (you can choose between immediate action and 2-second delay).

Unfortunately, the current  D5500  firmware  doesn't  allow the ML-L3 to be used for video.  To start and stop a video remotely, you may use one of the wired accessories described next and make the following  deep  selection:

SETUP MENU   >   Accessory terminal
>   Remote control   >   Remote shutter release   >   Record movies

Cancel that by selecting  "Take photos"  instead, when done with videos.

Third-Party Cable Release, with Timer :

On the D5500, the connector to use for an electronic  cable release  is located topmost behind the side-door to the left of the screen  (below the Wi-Fi logo).  It's also used for the GPS accessory  (unlike the D5300, the D5500 doesn't have GPS built-in).  Some vendors have released  (to mixed reviews)  GPS receivers combined with with cable releases which make use of both functions of that port!  (Here's how to make your own Nikon GPS.)

Nikon's standard cord  (MC-DC2)  doesn't take batteries  (it's purely mechanical).  The locking button on it simulates perfectly the release button of the camera, including the halfway feature normally used to initiate autofocusing.  The Nikon unit goes for  $22  but a good work-alike is  $10.

However, what I recommend is a cable release  with a timer.  Nikon doesn't make one.  Such a unit requires batteries for its timer only.  When batteries are not installed, it works exactly like Nikon's MC-DC2.

That's to say, the big button on the remote acts just like the camera's own release button, which you no longer need to touch.  This removes the major source of camera-shake and makes a  tripod-mounted more reliable when shooting with a telephoto lens at moderate shutter speeds or any lens at slow speeds,  including long exposures using "bulb" or "time" shutter modes.  (In traditional cameras, the shutter was pneumatically controlled by an air bulb, which you squeezed for as long as you wanted the shutter to stay open.)
Another known source of residual vibrations are mirror bounces.  To eliminate that problem, some cameras offer to delay release after raising their mirrors  (a one-second delay is more than enough).  On the Nikon D5500, the d1 sub-menu takes care of that.

 Cable release, with timer.  For $18,  I bought the popular unit shown at right, sold under several discount brands like  Neewer®  (mine bears a "Shoot" logo).  Its large locking button functions like the button of an MC-DC2, with or without batteries in the unit.  (If there are batteries, the LED becomes green when the button is pressed half-way and red if it's pressed all the way.)  The battery-powered timer is a very useful addition.  Five independent parameters can be programmed, for automated shooting:

  1. Delay before the first shot.
  2. Duration of each shot  (if the camera shutter is in "bulb" mode).
  3. Interval between the end of one shot and the beginning of the next.
  4. Number of shots  (either unlimited or any number from 1 to 399).
  5. Beep  (during long exposures)  on or off.

Press the center of the  D-pad  (labeled SET)  to modify whatever parameter is underscored by the cursor at the top of the LCD screen.  If that parameter is a time  (#1, #2 or #3)  you may use sideways motion on the D-pad to pick the units to modify  (hours, minutes, seconds).  You use up or down directions to change the  (blinking)  selection.  Once satisfied with that setting, press SET to validate your choice.

You may then use the D-pad sideways to select another parameter and visualize its current value  (which you may modify, if desired, using the procedure just described).  For the number of shots, the setting between 399 and 1 is displayed as  "--"  which indicates that the unit will keep firing until the sequence is aborted  (with the TIMER START/STOP button).

Parameters #4 and #5  (number of shots and beeping mode)  are always displayed on the second line of the LCD  (where a musical note is shown when beeping is active).  No time is displayed  (on the first line)  when either of those is selected.  When it's not silenced, the unit beeps once per second during  long  exposures  (i.e., when parameter #2 is nonzero).

When parameter #2 is set to zero, the unit will actually send pulses lasting  0.2 s  and the duration from the start of each pulse to the next is thus equal to  0.2 s  plus a whole number of seconds  (namely, the value of parameter #3, which can't be zero).

The top-right button  (labeled TIMER START/STOP)  is used to start the programmed sequence, or abort it.  During a sequence, the LED is green two seconds before each shot and glows red  during  every shutter release.

The unit has no on/off switch because it consumes very little current when it's neither in a sequence of shots nor in the setting mode  (as indicated by some blinking on the LCD, including at least one of the three indicators on the bottom line: "TIMER ACTIVE", "SET", "RELEASE").

The top-left button can be pressed briefly to provides a few seconds of backlight.  When pressed for a long time, that button forces the unit into  (or out of)  a  locked  state where all other buttons are disabled, as indicated on the LCD by a large "L" in a black square.  This helps the unit survive unprotected in a camera bag.

The unit suffers from a few inconsequential  design flaws, namely:
The firmware won't properly issue one beep per shot when the unit is set for short exposures  (i.e., when parameter #2 is zero).  Beeps are actually generated at a constant rate of one pulse per second  not synchronized with releases  and just muted between shots.  So,  most brief shots will be silent, as no such pulse occurs during exposure.
locked  unit will still light up when the top-left button is pressed.
One last minor gripe:  There's no way to dim the LED or turn it off completely  (for nighttime photography).  Once you're satisfied that the unit works properly, the LED can be a visual nuisance which only drains the batteries unnecessarily.  To remedy that, I am considering putting a switch in series with the LED  (with or without a potentiometer).  The battery compartment provides ample room to install that, without ruining the look and feel of this nice unit.

On the other hand,  I love the fact that all timing parameters are set in increments of one second  (up to 99 hours, 59 minutes and 59 seconds)  using a uniform procedure.  Exposure durations using the camera "bulb" mode aren't restricted to any predetermined sequence  (like the usual sequence of long exposures:  3, 4, 5, 6, 8, 10, 13, 15, 20, 25, 30, 40, 50...)

Here are a few creative ways to use this cable release.  The first example makes no use of the timer  (it can be used with any cable).

  • Set the camera at a shutter speed of thirty seconds in continuous shooting mode  (at high or low rate;  it doesn't matter).  Push the main button on the release and lock it with the slider.  The camera will then take a continuous sequence of 30 s exposures with only a fraction of a second between shots.  (See how  Tony Northrup  uses this technique to get a good image of star trails.)
  • Set the shutter to "Time" rather than "Bulb" to obtain a series of pictures where the shutter is open exactly 50% of the time.  The duration of every exposure is the sum of parameters #2 and #3  (interpreting a zero value of #2 as  0.2 s):  1.2 s,  2 s,  2.2 s,  3 s,  etc.
  • Determine experimentally what effective shutter speed is obtained when parameter #2 is set to zero and the camera is set on "Bulb".  HINT:  Instead of assuming  1/5 s  from the above timing considerations, just photograph an object of known speed  (e.g.,  take a picture of a vertical ruler with a falling marble released in front of it at position zero, shortly before the shot).


One of the latest trends in digital cameras is the use of Wi-Fi for communications.  Nikon's Wireless Mobile Utility promises that immediately with "your smartphone or tablet".  Does it deliver?  Well, not necessarily; the app can only be installed on  compatible  devices.  My Chinese Irulu tablet isn't.  What's the technical reason for that?

(2015-06-02)   Geotagging with an external GPS receiver
How the camera receives information from an external GPS module.

Here's the pinout of the cable to the GPS/remote port.  As noted above, the connector accommodates a purely mechanical cable remote  (which connects #5 to #3 for a half-press and #6 to #3 for a full-press of the release button).

 MC-DC2 release button and GPS data
Cable View
  1.   ?
2.   TX   (from camera).
3.   Ground (0 V)
4.   Vcc (+5V)
  5.   Half-press  (focus),
6.   Full-press  (shutter).
7.   RX   (GPS data, to camera).
8.   ?

GPS module communicate using the NMEA 0813 standard (National Marine Electronics Association).  That standard allows one-way communication from a single  talker  (the GPS module)  to several  listeners  (making it possible to connect  in parallel  devices like cameras, display units, computers or microcontrollers).

Balanced lines are recommended but the standard also allows the simple TTL-level signals which Nikon uses.  Asynchronous serial communications is performed with no handshake at 4800 bauds, 8 data bits  (bit 7 being 0)  no parity and one stop bit.

A GPS module sends full  sentences  consisting of a line of printable ASCII characters ending with a carriage-return  (CR = ASCII 13)  and line-feed  (LF = ASCII 10).  Every sentence starts with a dollar sign  ($)  followed by no more than 80 characters before the end-of-line  (CR+LF).  Just before that end-of-line, a checksum can inserted which consists of a "*" followed bt two hexadecimal digits.  Those hexadecimal digits represent the byte obtained bitwise addition  (XOR)  of all ASCII characters between $ and * (both excluded).  A sentence may contain several fields separated by commas  (a field may be empty).

The initial "$" is followed by a 5-character formatter of one of three kinds:

  • The Nikon oddball  "NKGCS"  which replaces  "$PGRMM"  (see next)  in modules meant to interface with Nikon cameras  (including the Solmeta Geotagger).
  • The letter "P"  (for "proprietary")  followed by a three-letter manufacturer ID and a single-letter format code specified by that manufacturer.  One of  many  examples of the former part is  "GRM"  for  Garmin Corporation,  in which case the latter single-letter format code might be  "M"  for  "Map datum",  yielding the aforementioned complete prefix  "$PGRMM".
  • A two-character identification of the type of talker  ("GP" for GPS module)  and a three-letter format code, like  "RMC"  for the "recommended minimum GPS data"...

For a GPS talker using a "$GP"  prefix,  Glenn Baddeley  has compiled more than 60 different NMEA 5-letter formats and gives detailed information about 26 of them, including $GPRMC and $GPGGA.

listener  won't understand every possible NEMA format and may not care about some fields within its recognized formats.  Nikon cameras apparently only pay attention to the four formats presented below  (where the characters "--" are wildcards which stand for "GP" or any other talker ID).

RMC = Recommended Minimum Data for GPS. 11 fields + checksum:
 1) Time (UTC)
 2) Status, V = Navigation receiver warning
 3) Latitude
 4) N or S (North or South)
 5) Longitude
 6) E or W (East or West)
 7) Speed over ground, knots
 8) Track made good, degrees true
 9) Date, ddmmyy
10) Magnetic Variation, degrees
11) a = E or W  (Easterly or Westerly)
 *) Checksum

GGA = Global Positioning System Fix Data. 14 fields + checksum:
 1) Time (UTC)
 2) Latitude
 3) N or S (North or South)
 4) Longitude
 5) E or W (East or West)
 6) GPS Quality Indicator 
    (0 = no fix, 1 = GPS fix, 2 = Differential GPS fix}
 7) Number of satellites in view  (00 to 12)
 8) Horizontal Dilution of precision
 9) Antenna Altitude above/below mean-sea-level (geoid)
10) Units of antenna altitude, meters
11) Geoidal separation
    (height of mean-sea-level geoid above WGS-84 reference ellipsoid)
12) Unit of geoidal separation (M for meters)
13) Age of differential GPS data, time in seconds since last SC104
    type 1 or 9 update, empty field when DGPS is not used
14) Differential reference station ID, 0000-1023
 *) Checksum

$NKGCS,WGS 84*11
$NKGCS = Nikon Global Coordinate System (??). Replaces the following:
$PGRMM = Map Datum (Garmin proprietary sentence). 1 field + checksum:
 1) Currently active horizontal datum (WGS 84, NAD27 Canada, ED50, a.s.o)
 *) Checksum

HDG = Heading, deviation & variation. 5 fields + checksum:
 1) Magnetic Sensor heading in degrees
 2) Magnetic Deviation, degrees
 3) Magnetic Deviation direction, E = Easterly, W = Westerly
 4) Magnetic Variation degrees
 5) Magnetic Variation direction, E = Easterly, W = Westerly
 *) Checksum

When it's directly mounted on the camera's hot shoe, a GPS module with a built-in magnetic compass can let the heading  ($HCHDG)  indicate the geographical direction of the shot.  An onboard accelerometer would be able to determine the  pitch  angle  (tilt or jaunty angle)  and  roll  as well  (Dutch angle or apparent inclination of the horizon).

Adding heading, pitch and roll (HPR) information to the EXIF header is a relatively new concern  (2012).  I don't know how good the Nikon software is at processing pitch and roll information from the units that provide it  (in particular via $PTNTHPR sentences).

Geotag   |   NMEA Data  (Dale DePriest)   |   GPS Connection with a Nikon DSLR   |   MC-DC2 Pinout

(2015-05-14)   External power for Nikon's  D5200, D5300 and D5500
EP-5A cable coupler and EH-5 power supply  (AC)  are sold separately.

Nikon's EP-5A (DC-coupler) physically replaces the battery and routes a cable through an otherwise unused opening out of the battery compartment.  Outside, the cable is attached to a proprietary Nikon connector.

The connector from the  EP-5A then plugs into an EH-5b power supply  (Nikon's newer version of their older EH-5, which still works fine).

Nikon's original parts are wildly overpriced  ($39 for the EP-5a and $90 for the EH-5b on Amazon).  Third-party solutions are more reasonably priced  ($40 for both items, instead of $129).

(2015-05-29)   Tripods
A small selection at various price points.

You need at least one tripod.  Many types of interesting photos can't be shot without one.  Get yourself an inexpensive model if you must; it can always be recycled later into a good lightstand when you upgrade to a better model.

For the utmost in comfort, plan to use the tripod standing completely upright with the camera visor at eye-level.  That requires an extended height at least equal to your own height minus  7''  (178 mm).  Anything taller is only useful to support lights.  Anything smaller will force you to stoop a little...

When weighing down lightweight tripods, good stability is achieved by putting your whole camera bag in a low-hanging stonebag.  However, a stonebag is a relatively bulky item to carry...  If the tripod is equiped with a hook at the bottom of the center column, a better option is to tie a bungee from that hook to your bag underneath.  In windy conditions, this is a must.

It's a  bad  idea to hang something on the hook instead  (less stability and more stress on the tripod).  Do carry a good bungee cord with hooks on it...

72-inch  Bower  Tripod   $30

That tall basic tripod is inexpensive but decent.  It features a carrying handle  (attached between the column and the head)  and comes with a carrying bag.

The three-sections aluminum legs with lever-locks have foam-grips at the top.  A self-centering geared aluminum column, with a locking ring, raises the head to the desired height using a small crank.  The base has a bubble level to make sure the column is vertical.  The panoramic head has a locking handle and a tilt level.

The construction involves rivets and heavy-duty plastic.  This tripod can easily withstand normal use but no amount of abuse.

Carbon Fiber Travel Tripod

The no-frills  Amazon Basics  model  ($80)  extends chest-high to  52'',  (1320 mm)  folds down to  12.4''  (315 mm)  weighs  2.2 lb  (1090 g)  and can withstand a  12 kg  load.

Carbon Fiber Travel Tripod / Monopod / Macro-Stand

My  Zomei Z669c  model  ($150)  took two weeks to come from China  (June 2015).  Worth the wait.  It's desirable because of its looks, quality, price and versatility.  It extends to  61.4''  (1560 mm)  folds down to  13.8''  (350 mm)  weighs  2.9 lb  (1320 g)  and can withstand an  8-12 kg  load.

The legs can be locked in two different positions.  The wide-angle position provides a large base even when the legs are not fully extended.  This is a nice option in unusual situations where the full height of the tripod is not needed or not desired.  (Tabletop use, for example.)

The center column has a detachable hook.  The column can be reversed to transform the tripod into a macrophotography stand or allow a very low position of the camera  (for the ultimate in flexibility, you may want to get an all-metal accessory  ($6.80)  which allows you to hang the camera securely from its hotshoe).  In a pinch, you can reverse the legs instead of the column  (in this makeshift configuration, the angle of the legs can't be locked but the joints are stiff enough to make a narrow angle stable).

One leg of the tripod can be detached and assembled with the center column to form a good monopod,  58'' in height  (62'' with the ball-head).  Generic ball-head

The ball-head supplied with this tripod has been re-branded under several names.  It's hefty and well-built but its independent locking panoramic joint is much too stiff  (that's my only complaint about this tripod kit).  The head can be detached for other uses, including the DIY project described in the next section  (it's a 3/8'' joint,  not 1/4'').

This ball-head is great on a monopod, where the panoramic joint is irrelevant.

 Panoramic head branded Koolehaoda Because panoramic shots can be important to me, I chose to replace the above kit ball-head by the fluid-damped panoramic head shown at left.  It's branded  Koolehaoda,  but the style is so similar to the  Zomei  unit that I suspect it to originate from the same manufacturer...  This head doesn't allow the legs to be folded back completely.

With the pan-head attached, the tripod will thus only collapse down to a height of  20''.  The flat space at the top of the column can accommodate a third-party  18 mm circular bubble spirit level  to check verticality.

Monopod and Hiking Stick :

One of the highest praise that can be given to the sturdiness of a photographic monopod is that "it can be used as a hiking stick".  Few can.  If that's what you have in mind it can be better to get a  real  wooden hiking stick  (the standard length is 55'')  and convert it into a monopod...

To do so, flatten the top of the hiking stick and drill a hole in the center to secure a long threaded rod protruding a bit,  to match whichever standard fits your ball-head  (adapters are available but the result will be less sturdy).

For durability, a metal ferret around the wooden stick is a nice addition which isn't absolutely necessary  (manufacturers of 3-piece hiking sticks often omit ferrets to save costs).

My local Ralphs supermarket  sells  ($20)  a suitable wooden 3-piece 55'' hiking stick from China, under the brand  Live Well Life Styles  (WS115-3PC).  For the same price, they also carry single-piece hiking sticks which are better if you don't have to travel by plane...

Threaded Studs   ( 1/4''  or  3/8'' )

Following the lead of the legendary Brownie camera,  almost all consumer cameras feature a  1/4''  coarsely-threaded socket to secure them to tripods  (1/4-20 UNC, per ISO 1222).  Mamiya 645 tripod mount

Instead, some professional cameras  (medium format or larger)  use the sturdier  3/8''  standard  (3/8-16 UNC).  Examples include all Hasselblad cameras and my own  Mamiya 645,  pictured at right with the thread-reducer which allows the use of regular grips and tripods.

The current trend is to use the larger studs  (UNC 3/8-16)  to connect detachable tripod heads to tripods and the smaller ones  (UNC 1/4-20)  between tripod heads and not-too-large cameras.

On older cameras and tripods, the BSW versions of those two were used  (British Standard Whitworth) .  The UNC and BSW threads have slightly different tooth profiles  (UNC is 60° with flat crest, BSW is 55° with rounded crest).  They can mate, but knowledgeable people will never force them upon each other  (which amounts to having the threads retool one another).  Nowadays, BSW standards are all but entirely obsolete  (including the smallish  3/16-24 BSW,  which has no current UNC counterpart).  Microphones use a  5/8-27 UNC  mount.

Following the nominal diameter in the specification of a threaded rod is the number of threads per inch  (TPI).  In photography, it's  always  understood that  1/4''  screws are 20 TPI while  3/8''  screws are 16 TPI  (the UNC profile being used in both cases).  Therefore, quoting the diameter suffice,  unless you use general hardware supplies in DIY photography projects.

It's also important to know what height either type of stud is supposed to be.  Longer studs could damage the mounting sockets of expensive cameras while shorter ones would provide less reliable fastening.  Some manufacturers give explicitly the maximum screw length their camera sockets can safely sustain.  5 mm is always safe.

  • Lumix DMC-ZS25:  1/4'' screw shorter than 5.5 mm  (0.22'').

Steady telephoto shooting (9:30)  by  Ken Wheeler   (2015-06-19).

(2017-01-27)   Camera bags  &  Cases
Travel and Storage.

 Come back later, we're
 still working on this one...

Lowepro Vertex 300 AW : Protection when travelling (11:30)  by  Karl Taylor   (2012-03-23).
Camera bags:  What to take with you (9:35)  by  Nick Murray   (2013-03-24).
The KING of all Think-Tank camera bags! (15:09)  by  Adam Lerner   (2014-10-16).

(2015-05-08)   Nikon Lenses
History and personal memories.

With my (black) Nikon-F1 "Photomic FTN" body.  In order of purchase:

 Come back later, we're
 still working on this one...

 Xit macro extension tubes for Nikon
(2015-06-21)   Macro extension tubes
Buy only  automatic  extension tubes.

By increasing the distance from the lens to the focal plane, extension tubes allow an ordinary lens to focus at smaller distance than what it's normally capable of, with little or no decrease in image quality.  The only drawback compared to  specialized macro lenses  is a significant darkening or the field for extreme close-up.

The widely-available set of  Xit ™  automatic extension tubes pictured at right will set you back between $41 or $45  nowadays.  It consists of three tubes  labeled  12 mm, 20 mm and 36 mm.  Incredibly enough, two of those numbers are incorrect!

The actual extension they provide are  13 mm19 mm  and  36 mm.

Beyond the mistake that one engineer made,  what I find difficult to believe is that nobody noticed that until now!  One foolproof way to measure the extension of each tube is to put two of them together and measure the whole thing using calipers  (include endcaps if you must).  Repeat the measurement for only one of the tubes  (with the same endcaps you had the first time around)  and  subtract  from your previous result to obtain precisely the extension provided by the  other  tube.  What I got, to the nearest tenth of a millimeter,  was:  12.9 mm,  19.1 mm  and  35.9 mm!  To quickly confirm the mistake so detected, notice that the plastic collar is  6 mm  thicker in the second tube compared to the first one  (the difference would have been  8 mm  if the manufacturer's markings had been correct).

To correct the labels, I blackened the erroneous numbers with a Sharpie, wrote the good ones with a coarse silver Sharpie with a bit of touch-up from a fine black sharpie.  This looks like a hand calibration, as it should. 

Correct  focus extensions provided by the above set of tubes  (Xit ™ )
13 mm19 mm32 mm36 mm49 mm55 mm68 mm

 Manual extension tubes for Nikon F-Mount   Except for basic experimentation  (pinhole and such)  avoid  manual extension tubes  ($8.39 on eBay)  which have neither  electrical  couplings  (auto-focus and vibration reduction)  nor mechanical coupling  (aperture).
Those are all but useless with G-type lenses  (which lack aperture rings).

The generic set pictured above consists of two end pieces providing a combined extension of  15.8 mm  (use any other complete extension set to measure that value, with the above differential method).  The three intermediate threaded tubes  (57 mm thread)  are numbered 1, 2 and 3.  They provide additional extensions of 7 mm,  14 mm  and  28 mm.  That makes it possible to obtain eight different equally-spaced extensions:

15.8 mm  +  (7 mm) n         for   n = 0 to 7

If the third tube had been labeled "4" instead of "3", we could have described the above "n" as the sum of the labels printed on the tubes used...  Too bad.

Extensions provided by the above generic set of tubes  (to the nearest mm)
16 mm23 mm30 mm37 mm44 mm51 mm58 mm65 mm

As an exercise in arithmetic, the combination of the above two sets of tubes allows the following 57 different extensions  (in mm)  in manual mode.  Six of them  (underscored)  are obtained in two different ways  (within 0.2 mm of each other):  13,  19,  29,  32,  35,  36,  42,  43,  48,  49,  50,  52,  55,  56,  57,  59,  62,  64,  65,  63,  66,  68,  69,  70,  71,  72,  73,  76,  77,  78,  79,  80,  83,  84,  85,  86,  87,  90,  91,  92,  93,  94,  97,  98,  99,  100,  101,  105,  106,  107,  112,  113,  114,  119,  120,  126,  133

 Aperture Control Ring for 
 Nikon Lens in Reverse Mount
(2016-12-17)   Lens in Reverse Mount
On body or in front of another lens.

As G-lenses don't have aperture rings, you need a special device on the bayonet side of a G-lens to operate its aperture when it's reversed.

(2015-05-14)   Sharp normal lens for low-light conditions   ($167-$197)
Nikon 35mm f/1.8G AF-S DX

 Nikon 35mm f/1.8G AF-S DX   52 mm  filter size.  HB-46  hood.
DX reach:   54 mm  (normal).
No distance indicator on lens.

Inexpensive.  Great optical qualities.  No VR image stabilizer  (must shoot handheld at  1/60 s  or faster).

9F 58 44 44 14 14 A1 06:  Nikon AF-S DX Nikkor 35mm f/1.8G

(2016-11-29)   Portrait lens for low-light conditions   ($177-$217)
Nikon 50mm f/1.8G AF-S FX   (would be a normal lens for full FX).

 Nikon 50mm f/1.8G AF-S FX   58 mm  filter size.  HB-47  hood.
Usable with FX cameras.
DX reach:   77 mm  (portrait).
Minimum aperture  f/16

Affordable, full-frame.  Aspherical optics.  No VR image stabilizer  (must shoot handheld at  1/60 s  or faster).

B0 4C 50 50 14 14 B2 06:  AF-S Nikkor 50mm f/1.8G

(2015-05-14)   Macro lens  &  long portrait lens   ($527)
Micro-Nikkor 85mm f/3.5G AF-S DX ED VR

I never had the comfort of a dedicated macro lens before.  The experience was a revelation and this pricey lens is now a favorite.

 AF-S DX Micro NIKKOR 85mm f/3.5G ED VR   52 mm  filter size.  HB-37  hood.
DX reach:   130 mm  (long).

The aperture range is:
f/3.5 - f/32  when focused at infinity,
f/5 - f/45  at a 1:1 reproduction ratio.

The VR image stabilizer is pointless in tripod macro-photography but allows this sharp lens to be used very comfortably for portrait  (in spite of the  1:3.5  aperture which can't bring about extreme bokeh).

The manufacturer's rating of three f-stops for the VR stabilizer would allow this lens to be used for portrait at  1/15  (instead of  1/125 s  normally).

A7 4B 62 62 2C 2C A9 0E:  Nikon AF-S DX Micro Nikkor 85mm f/3.5G ED VR

(2017-02-07)   Portrait Lenses  ( zooms  &  primes )
Wide apertures and long focal lengths.  An overview.

Best Lenses for Portrait Photography  by  Vivian Liu   (2016-08-10).
Video : Tamron 70-200mm f2.8 G2  by  Matt Granger   (2017-02-06).

(2015-05-14)   Superzoom  (16.7 x)  travel lens   ($615-$897)
Nikon 18-300mm f/3.5-6.3G AF-S DX VR

 Nikon 18-300mm f/3.5-6.3G AF-S DX VR   67 mm  filter size.  HB-39  hood.
DX reach:   28-460 mm  (telephoto).
No focus distance indicator on lens.

Not to be confused with its predecessor:
Nikon 18-300mm f/3.5-5.6.

The manufacturer claims that the VR image stabilizer allows a gain of  4  f-stops,  which means that the lens could be operated handheld, in the longest telephoto position, with a shutter as slow as  1/30 s  (instead of  1/500 s  without VR, according to common wisdom).

A4 40 2D 8E 2C 40 BF 0E:  Nikon AF-S DX Nikkor 18-300mm f/3.5-6.3G ED VR
 Nikkor 200-500mm f/5.6E ED VR
(2017-01-05)   Telephoto Zoom
AF-S Nikkor 200-500mm f/5.6E ED VR   ($1212-1399).

Included:  tripod collar,
HB-71  hood, end caps.
LC-1434 pouch included.
95 mm (1 mm pitch)  filters.
Usable with FX cameras.
DX reach:   307-767 mm.
D500 reach for 4K video:  455-1164 mm Electromagnetic aperture (E).
Close focus:  2.2 m  (7.22').
Reproduction ratio:  1 : 4.
Iris: 9 rounded blades.
Minimum aperture:  f/32.
19 elements in 12 groups
(including three in ED glass).
Mass:  2.3 kg, with collar.
4.5 stops of Vibration Reduction (sports mode).
Compatible with modern Nikon teleconverters
(1.4, 1.7 & 2.0) retaining
autofocus only for 1.4 with f/8 camera (e.g., D500).
Product page  |  Specifications

AE 3C 80 A0 3C 3C C9 4E:  AF-S Nikkor 200-500mm f/5.6E ED VR

Nikon 200-500mm VR  by  Ken Rockwell  (October 2015).
Nikon 200-500mm f/5.6E Lens Review  by  Thom Hogan  (2015-12-16).
Videos :   Awesome!  Nikkor 200-500mm  Ken L. Wheeler,  (Theoria Apophasis, 2016-03-25).
Nikon 200-500mm f5.6 lens review  LensVid (2016-02-10).
Nikon 200-500 f5.6 with a Gimbal Head  by  David Tothill.  (LensMaster RH2)

Competing Third-Party Ultra-Telephoto Zoom Lenses  150-600mm f/5-6.3
Tamron Sigma
2014-07 2016-09 2014-09-12
$870 $1400 $990 $1600-2000
Made in China Made in China Made in China Made in Japan
95 mm filters 95 mm filters 95 mm filters 105 mm filters
1.95 kg 1.99 kg 1.95 kg 2.86 kg
2.70 m  /  1:4.3 ? 2.20 m  /  1:3.9 ? 2.80 m  /  1:4.5 ? 2.60 m  /  1:4.2 ?
Product page Product page Product page Product page
Matt Granger
Christopher Frost
Matt Granger:  G2, | Surf
Kristopher Rowe
Jared Polin Iain Challis
Tony Jeeves + calibration
Dustin Abbott :  Presentation | Conclusion Explore the Sigma 150-600mm Sport & Contemporary
with Roman Kurywczak.

Hoods for FX Zoom Telephoto Lenses in DX Photography :

All of the above are FX lenses.  The hoods provided for them by the manufacturer are adequate, but not optimal.  There are two reasons for that.  First, those hoods are designed to avoid vignetting at the shortest focal length; a hood designed fot the longer end would be much narrower.  Second, we can use for DX photography narrow hoods which would cause vignetting in "full-frame" FX photography.  This includes affordable cyclindrical hoods,  consisting of  95 mm  blackened aluminium tubing with black-felt lining and filter threads  (one male, one female).

My own solution is to add a cheap screw-on  Promaster Rubber Hood  at the end of one of these,  which provides a great base for a strap-on DIY sleeve in the most critical cases  (without interfering with the zoom ring).

A Better Lens Hood for the Nikkor 200-500 f5.6  by  Sean Michael.
CNC 95 mm Cylindrical Hoods with Filter Threads :   Length 39 mm  ($17.89)  |  Length 78 mm  ($25.89)

Measuring the Reproduction Ratio :

The above data for the Tamron and Sigma lenses are just guesses, as I don't have access to them  (if you do,  please send me your results,  which I'll publish here with due credit).  The data given online by Nikon and mindlessly repeated by reviewers  (1:4.5)  is clearly incorrect.  I measured the reproduction ratio of the Nikkor lens to be about  1:3.997  (the main source of error being the depth of field, as I achieved focus by moving the camera back and forth).  I simply took a sharp picture of a good ruler at longest focal distance and shortest focusing distance.

The ruler I used is a calibrated laser-imaged  Cobalt Precision Rule  from Grayson Precision Technologies, Inc.  (P.O. Box 2060, Edison, NJ 08818-2060).  It was state-of-the-art back in 1995  (if I remember well, I got it for less than $10 at a graphics-art store)...

Blowing up the image of a near-horizontal ruler,  it's fairly easy to determine the distance of two points to the nearest half-pixel  (that's an uncertainty of one quarter-pixel).  I found that the images of two points 93.5 mm apart had an horizontal separation of 5982.5 pixels and a vertical separation of  46 pixels.  that made the distance between the images nearly equal to  5982.7 pixels.  With the D5500 camera,  assuming a  pixel pitch of exactly 3.91 microns,  that corresponds to a distance of  23.3924(13) mm.  This yields the  measured  reproduction ratio quoted above, namely:

93.5 / 23.3924   =   3.99703...

It wouldn't be prudent to  compute  the reproduction ratio of a complex lens without knowing unpublished optical details  (in particular, the effective focal length varies significantly at close focusing distances).

Nikon 200-500 vs. Sigma 150-600 Sport  by  Jared Polin   (2015-11-28).
AF-S Nikkor 200-500mm f/5.6E ED VR  vs.  AF-S Nikkor 400mm f/2.8G ED IF VR  by  Özkan Özmen   (2016-11-21).
Sigma 150-600 Sport vs. Tamron 150-600 G2  by  Kevin Dooley   (2016-12-27).

(2015-05-14)   Fast wide-angle zooms from Tokina
Tokina 11-16mm f/2.8 AT-X Pro DX II  (AF-S IF)   ($440-$467)
Tokina 11-20mm f/2.8 AT-X Pro DX,  March 2015   ($523-$568

 Tokina 11-16mm f/2.8 AT-X Pro DX II (AF-S IF)    Tokina 11-20mm f/2.8 AT-X Pro DX
Nov. 2007  (type II since 2012)
11-16mm f/2.8   (17-25 mm  reach)
77 mm  filter size.  BH-77A  hood.
550 g   No vibration reduction (VR)
Product page   |   Ken Rockwell (2008)
March 2015
11-20mm f/2.8   (17-31 mm  reach)
82 mm  filter size.  BH-821  hood.
560 g   No vibration reduction (VR)
Product page   |   Matthew Saville   |   Ken Rockwell

As the DX crop factor makes FX short lenses inadequate,  specific DX lenses are required for wide-angle photography.  The above two lenses compete with the  Nikkor 10-24 f/3.5  (which has a wider zoom range but is significantly slower).  Shorter (expensive) zooms are available but there are slow and their usefulness is debatable.  Arguably,  extremely wide angles are the exclusive realm of  fisheyes  with recognizable pronounced distortions.

Videos :   Tokina 11-16mm f/2.8 AT-X Pro DX II  hands-on review,  by  Kai Wong  (Oct. 2012).
Tokina 11-16mm f/2.8 AT-X Pro DX II  by    (Dec. 2015).
Tokina 11-20mm f/2.8 Pro DX Lens Review  by  Matthew Saville  (2015-03-17).

00 48 1C 29 24 24 00 06:  Tokina AT-X 116 PRO DX (AF 11-16mm f/2.8)
7A 48 1C 29 24 24 7E 06:  Tokina AT-X 116 PRO DX II (AF 11-16mm f/2.8)
7A 48 1C 30 24 24 7E 06:  Tokina AT-X 11-20 F2.8 PRO DX (AF 11-20mm f/2.8)

(2015-05-14)   Third-party ultrawide fish-eye lens   ($283.50)
Samyang / Rokinon 8mm f/3.5 AE   (DX for Nikon)

Rokinon 8mm f/3.5 AE fisheye   No filters.  Built-in hood.
DX reach:  12 mm  (at center).
No autofocus.

This lens also comes in an inferior version without AE  (auto-exposure)  whose aperture can't be controlled by the camera.

With a fisheye lens, everything looks in focus.  The old-school method is to turn the focus ring to an estimated distance to the main subject, then frame and shoot  (at  1/15 s  or faster, if handheld).

Unlike G-type lenses, this lens possesses an aperture ring which you set to the top setting  (f:22, marked in red)  to let the camera operate the iris.  The camera will remind you to do so, if you forget.

4A 40 11 11 2C 0C 4D 02:  Samyang 8mm f/3.5 Fish-Eye CS
The $0C in the above LensID should be ignored by camera bodies  (it would correspond to the aperture at the telephoto end if this lens was a zoom).  Instead, the D5500 (and others?) mindlessly report this lens as "8mm f/3.5-1.4" [sic].

(2015-05-23)   Lens Hoods   (French:  pare-soleil )
Bayonet hoods for Nikon lenses.

The primary function of a hood is to prevent undesirable light rays from entering the lens.  By illuminating the optics at high angles, stray light could cause a variety of unsightly spots and blotches on the final picture.

The inside of the hood should have some good black treatment  (genuine Nikon hoods are outstanding in that respect).  A shiny hood could be worse than no hood at all by bouncing into the optics some additional stray light.  The surface treatment on the outer part of a lens hood is utterly irrelevant.

Some  generic  lens hoods are available which simply use filter threads of a given diameter.  However, dedicated bayonet hoods are generally preferable because they can be mounted faster and do not interfere with filters  (in critical cases, stacking filters and/or such screw-in hoods can cause vignetting).  The one drawback of bayonet hoods is that they are often not compatible with step-up rings  (the rarely-used solution is to mount a screw-type hood directly on the larger filter, but this has other drawbacks).

For a zoom lens, a hood accomodating the shortest focal length offers little protection in telephoto settings.  The solution is to use either several hoods or a single three-position rubber hood.  Unfortunately, rubber hoods are not commercially available in bayonet mount  (you can make one by fitting the front part of a rubber hood to a sawed-off bayonet hood, but this is neither cheap nor easy to do).

With bayonet hoods, the main difficulty occurs at the time of purchase (especially when mail-ordering).  Nikon does offers many models of lens hoods but little or no guidance concerning their respective compatibilities with various lenses.

Firstly, the size of the bayonet on the hood must match what's on the lens.  Secondly, the shading part must not be so narrow as to cause vignetting or so wide as to offer little protection.

 Come back later, we're
 still working on this one...

Lens Hoods   Why, When, and How to Use Them.   by  Phil Steele.

(2017-01-30)   Scope Converter :  Erecting prism with 10 mm eyepiece.
A lens of focal length  L  mm  becomes a scope of  L/10  magnification.

 Nikon Scope Converter The magnifying power reveals lens aberrations that would remain undetected in most photographic applications.  With lenses f/3.5 or brighter, the exit pupil is 2.8 mm.

The Nikon original has been out of production for many years and now sells at a premium on eBay  (early in 2017, I got a nice copy at auction, unchallenged, for $150 + shipping; almost a bargain).

As this Nikon scope-converter was designed before the introduction of G-lenses  (which don't have an aperture ring)  it can't control the iris of a G-lens,  whose aperture must thus be kept open by a DIY plastic tab

Fortunately, no such DIY gizmo is needed for the  Nikkor 200-500, which is converted into a fantastic 20x-50x scope with a  1.75 mm  exit pupil.  (It seems that all other E-lenses also have their diaphragms fully-open by default, making them directly usable with the Nikon scope-converter.)

Nikon Lens Scope Converter  by  Ken Rockwell  (2006).
How to make your own lens scope converter for ~ $35  by  Darren Cokin  (2006-08-16).
Nikon Lens Scope Converter Turns Lenses into Telescopes  by  Michael Zhang  (2011-10-21).
Nikon Lens Scope Converter Turns Lenses into Telescopes  by  Fabrizio Belardetti  (2011-10-20).
Lens to eyepiece adapters  by  Bob Atkins  (2013-11).
Kenko Lens2Scope Adapter for Nikon Lenses (angled eyepiece)  (Adorama)
Kenko Lens2Scope Adapter for Nikon Lenses (straight eyepiece)  (Adorama)

(2015-06-14)   Nikon's F-mount pinout and electrical protocol:
Electrical connections between lenses and Nikon camera bodies.

 Pinout of a Nikon lens 
 (Nikkor 35 mm f/1.8G DX)   Recent Nikon bodies have 10 electrical lens contacts  (the D80 only had 7).  Most lenses have 8 pins or fewer  (forsaking pins 9 and 10).  Pin 4  is aligned with the central dot.  Pins 1, 2, 3, 4 and 7 are required for the basic serial communications supported by all Nikon-compatible digital lenses.

Pins 2 and 3 are open-collector bus lines  (10k pull-up resistors inside camera)
 Pin NameFunction  /  Description
A = 1Vcc+5 V regulated power (from camera) for digital circuitry.
B = 2H/SHandshake.  Can be asserted low by either device.
C = 3SIOSerial I/O data bus line  (open collector).
D = 4SCKSerial (asynchronous) clock,  from camera body.
E = 5AF feedback from lens  (50k pull-up resistor in camera)
F = 6LBAT+6.2 V  (switchable?) power source for lens motor(s).
G = 7LGNDLogical ground  (0 V).
H = 8HGNDHigh-current ground  (negative return path).
9Reserved for teleconverter use.
10Reserved for teleconverter use.
The exact function of pins 9 and 10 is still a mystery to me.  Those contacts are not present on the throat of any Nikon body.  They appear only on the throats of teleconverters and on the bayonets of lenses compatible with teleconverters.  Surprisingly enough, pins 9 and 10 are also present on the bayonets of teleconverters  (in spite of the fact that current teleconverters are not supposed to be stackable).
I've never experimented electrically with teleconverters but  I was told  that what the CPU of a teleconter does is just tell compatible lenses the value of its ratio  (1.4, 1.6, 1.7 or 2.0)  using pins 5, 9 and 10.  It's then up to the CPU of the lens to use that information to communicate with the camera.  Reportedly, in a teleconverter, all 10 pins on the throat side are tied directly to their respective counterparts on the bayonet side.

The 5 highlighted pins  (1,2,3,4,7)  implement the communication system described in several arcane Nikon patents:

This is a 3-wire synchronous serial interface, somewhat similar to a 2-wire I2C bus,  but with a separate handshake line  (on pin 2)  and a  5 ms  timeout.

Ground is on pin 7.  The camera body provides a +5V regulated voltage on pin 1  and acts as bus master by controlling the clock  (SCK)  on pin 4.  The other two pins are open-collector bidirectional bus lines with pull-up resistors located on the camera side  (10 kW on my D5500).

The functions of the other pins may be negotiated between lens and camera, using the communication protocol so implemented.

The camera tries to communicate using a  156 kHz  clock rate and falls back to  96 kHz  if the lens doesn't respond properly.

Communications start with the camera asserting H/S  (low)  for 1.6 ms.

Some command bytes  (hexadecimal)  in Nikon's camera/lens protocol :
00Fetch focal length.1990Patent
01Fetch full aperture.1990Patent
02Fetch LensID.1990Patent
0FFetch zoom position.1990Patent
22Fetch 25-byte lens data from non-D lens.  
27Fetch 41-byte lens data.1998Patent
28Fetch lens data  (new version).  
29Fetch 6-byte lens drive limit data.1998Patent
30Zooming drive.1998Patent
31Zooming inhibit.1998Patent
32Auto-focus drive.1998Patent
33Auto-focus inhibit.1998Patent
34VR drive.1998Patent
35VR inhibit.1998Patent
40Return capabilities and set mode
41Return mode previously set
FCFetch 2-byte conversion coefficient.1990Patent
FDFetch 8-byte auto-focus data.1990Patent
FEFetch 8-byte auto-exposure data.1990Patent
FFFetch all bytes from $00 to $0F.1990Patent

Originally, a lens which didn't recognize a command was supposed to send back a single #$FF byte.  Newer lenses will timeout instead.  (The earlier protocol seems better to me.)

Forum speculations (2008)   |   Pinout   |   Lens protocol   |   Foolography

(2015-06-14)   LensID and electronic signatures of lenses:
Rottmerhusen's database of Nikon-compatible F-Mount digital lenses.

Nikkor lenses and third-party F-mount lenses with a CPU chip  (Central Processing Unit)  have a stored "LensID" consisting of one or two bytes.  To reliably identify third-party lenses, Robert Rottmerhusen has combined this with other fixed data provided by the lens  (related mostly to focal length and aperture characteristics)  to form an  8-byte  Extended LensID.

He has compiled a database of about 500 lenses which some EXIF readers are using to identify the lens in the metadata attached to a JPEG picture.

At this writing, this method results in only seven ambiguities, mostly for different updates of the same lens.  Only three of them are significant:

# 2F 48 30 44 24 24 29 02:  Nikon AF Zoom-Nikkor 20-35mm f/2.8D IF
# 2F 48 30 44 24 24 29 02:  Tokina AT-X 235 AF PRO (AF 20-35mm f/2.8)
# 32 54 6A 6A 24 24 35 02:  Nikon AF Micro-Nikkor 105mm f/2.8D
# 32 54 6A 6A 24 24 35 02:  Sigma Macro 105mm F2.8 EX DG
# 7A 3C 1F 37 30 30 7E 06:  Nikon AF-S DX Zoom-Nikkor 12-24mm f/4G IF-ED
# 7A 3C 1F 37 30 30 7E 06:  Tokina AT-X 124 AF PRO DX II (AF 12-24mm f/4) 

Rottmerhusen's identifiers are known to consist of the following bytes:

  1. Single-byte legacy LensID  (possibly a misappropriated Nikkor ID).
  2. Nominal range of apertures  (unit  =  1/12 of an f-stop).
  3. Focal length at wide end  (see code below).
  4. Focal length at long end  (see code below).
  5. Maximum aperture at wide end  (1/12 of an f-stop,  $00 for f:1.0).
  6. Maximum aperture at long end  (1/12 of an f-stop,  $00 for f:1.0).
  7. CPU / MCU  version  (Lens SubID).
  8. Lens type.  A bitmap where bits seem to have the following meanings:
    • Bit 0 :   Masked to 0.  (1 = AF-S motor in lens).
    • Bit 1 :   1 if distance information is sent (AF-D or better).
    • Bit 2 :   1 if lens has no aperture collar (G type).
    • Bit 3 :   1 if lens has a VR motor.
    Examples:  $02=AF-D,  $06=AF-G,  $0A=AF-D VR,  $0E=AF-G VR.

Rottmerhusen says that all but the last byte  (lens type)  appear at addresses 12-18 in the EXIF "makernote tag" of an unmodified JPEG picture.

For a prime lens  (characterized by identical focal lengths at the wide end and the long end)  the  maximum aperture at long end  should be ignored  (in  at least one third-party lens  this is definitely junk data).  At least one Nikon body  (the D5500)  reports that piece of data on the back of the camera as if it was meaningful!  However,  there's no evidence that this junk data for a prime lens is actually  used  anywhere.

Single-byte encoding of focal length :

The encoding used for focal lengths in the above is a logarithmic scale.

Like any industrial sizes, focal lengths congregate around geometric progressions of preferred numbers, by design or necessity.  For historical lenses, the original coarse progression of focal lengths followed the photographic tradition of doubling every 3 steps.  Lineups were then refined as needed by designing new lenses at the geometric mean of existing focal lengths.  In the grand scheme of things, we ended up with elements of a geometric progression where doubling occurs after 24 tiny steps:

Relation between the focal length  (f)  and its single-byte modulus  (m)
f   =   2 m/24  u   where   u  =  4.953 mm  =  0.195''
or   u  =  4.9459 mm   (see below).

Conversely,  m  =  24 lg (f / u).  For example,  if  f  is  35 mm,  then  m  is:

24 lg (35 / 4.953)   =   24 log (35 / 4.953) / log (2)   =   67.7035...

Rounded to the nearest integer, that's  68,  or  $44  in hexadecimal.

This first value of  u  can be reversed-engineered as the middle of the interval  (from 4.946 to 4.960 mm)  which makes this type of conversion perfectly correct in 90% of the 50 unambiguous cases in Rottmerhusen's database  (the rest being construed as rounding errors).  u is also the only length in that interval to be a whole number of thou.

The converse operation is more delicate, since a rounded logarithm may not be sufficient to retrieve the original number.  In our example, 4.593 268/24  is only  32.735  which isn't an acceptable approximation of  35 mm,  unless you know what the aforementioned list of  preferred values  really is...

In some cases, a manufacturer may know more about the focal length of a lens than what's reported as a round number of millimeters and will adjust the code accordingly  (for example, codes $10 and $11 are both reported as 8 mm and the manufacturer may use the former or the latter depending on whether the actual focal length is slightly less of slightly more than 8 mm).

More annoyingly, although codes 47 and 49  ($2F and $31)  are respectively reported as 19 mm and 20 mm, the middle code  (48 = $30)  can be reported as either  (dubiously so for a focal length not exceeding 19.5 mm).

That particular case turns out to be the most critical of all.  It can only be accommodated by adjusting the base unit  u  to satisfy the equation:

24 lg (19.5 / u)  >  47.5   which means   u < 4.94590885...

Now, with the value  u  =  4.9459 mm,  we find that the database becomes  completely  correct if we just assume that manufacturers have reported an hexadecimal code for some actual focal length which is legitimately   rounded  to the advertised value in mm.  Here's the  complete  list of the cases which are consistent with that rule although the advertised focal length  (in mm)  doesn't fall within the range covered by the listed code.

Advertised focal lengths whose codes imply slightly different actual values :
AdvertisedCode ActualComments / Example
4.5 mm$00≥ 4.88Circular fish-eye (off the charts)
10 mm$19≥ 10.2($1A is advertised as  10.5 mm)
12 mm$1E≤ 11.93Samyang 12mm f/2.8 ED AS NCS Fish-eye
14 mm$25≥ 14.2Tamron SP AF 14mm F/2.8 Aspherical (IF) (69E)
15 mm$27≥ 15.1Sigma 15mm F2.8 EX Diagonal Fish-eye
19 mm$3019.5Tokina AF 193 (AF 19-35mm f/3.5-4.5)
20 mm$31≥ 20.1Nikon AF-S Nikkor 20mm f/1.8G ED
40 mm$49≥ 40.2Sigma 20-40mm F2.8
90 mm$65≥ 90.3Sigma 28-90mm F3.5-5.6 Macro
100 mm$69≥ 101.2Spectrum 7 100-400mm 1:4.5-6.7
170 mm$7B≥ 170.2Sigma APO 170-500mm F5-6.3 Aspherical RF
210 mm$81≤ 208.2Nikon AF Zoom-Nikkor 70-210mm f/4

This does justifies Rottmerhusen's approach of fully identifying a lens before reporting its focal length!

(2015-06-20)   EXIF data   (Exchangeable Image File Format)
The hidden data attached to every JPEG image made by  your  camera...

The EXIF metadata attached to digital pictures contains information formatted according to an evolving standard.  The constant upgrades are difficult to follow.  If that wasn't bad enough, it also contains a "MakerNote" part formatted differently by different camera makers from one of their cameras to the next.  Most camera manufacturers do not bother to publish their own format.  Nikon is just as bad as the others with that regard.  Most of what's known had to be reversed-engineered!

 Come back later, we're
 still working on this one...

EXIF reader software  by  Ken Rockwell  (2006).
What is EXIF data?   by  Nasim Mansurov  (2009-12-04).   Shutter actuations (2010-08-25).
Nikon MakerNote  (3 formats).

visits since May 26, 2015
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