"shooting blanks - EXIF says used focal length "0" at "F/0""
Shot 13 of those yesterday on assignment - the last 13 of the shoot, and today (even before removing the lens to visually inspect the contacts)the camera is acting fine.
All was nominal, changed metering from pattern to center weighted, and got gross underexposures thereafter. Don't see how that metering change could have been the cause. Guessing the body and lens weren't talking, or not properly. Per EXIF data body "thought" lens setting was f/0 - pretty wide! - anyway, used 1/1600 and up for those 13 shots (bright daylight, iso 320), and possibly sent no f stop setting at all to the lens, leaving it in fact at rest on f/22, thus all black shots. 24-70 2.8.
Ideas? If this was all a contacts issue (they seem clean), how to be sure it doesn't happen again? The lens seems tight on the body and I recall no impact (physical) damage such as might have caused alignment issues.
Apologies if this should have been posted elsewhere. Having problems with the topic pigeonholes.
#1. "RE: shooting blanks - EXIF says used focal length "0" at "F/0"" In response to Reply # 0
King City ON, CA
Yes, I had the same problem several months ago while shooting in a dense forest on a sunny day, a very high contrast lighting situation. I had to check each shot carefully for exposure since I have forgotten how well manual exposure works. Suddenly I had about a 7 stop under exposure. Took another shot, same. Turned the D700 off, then on, took another shot and all was well. EXIF reported: "Lens 0.0 mm f/0.0" for the two bad shots.
Simply turning the camera, off/on was all it took to fix the problem. That only happened to those two shots in almost 20,000 over 2 years and 6 months.
#2. "RE: shooting blanks - EXIF says used focal length "0" at "F/0"" In response to Reply # 0
Even though the electronics of the camera and lens have protection against being shorted out or voltage surges when being changed, it is a good idea to power the camera off when changing lenses and then re powering the camera. This will allow all the necessary circuits to re-initialize. This is even more important for any VR lens.
Even the many of the Nikon camera manuals states that camera should be turned off during lens changes.
#3. "RE: shooting blanks - EXIF says used focal length "0" at "F/0"" In response to Reply # 2
Thanks, George and wmarkle.
George, I really hadn't thought about turning off the camera for lens changes. Sounds like good procedure and I'll start doing that, but in this case the last lens change was many, many shots before the trouble.
And wmarkle, I sorta assumed that if the contacts are clean, and it's as rare as it's been, then it's just some of that stuff that happens. Inevitably. That's presuming it doesn't happen again.
As for checking often, agreed, though even if I saw the problem it might have taken me a while to blame the camera and do the on/off drill or reseat the lens. It's usually me somehow - not the camera - and looking at metadata would only come after checking every setting twice. Meanwhile, the pinata was being burst. When do we not check shots often? Given any sort of time element, when the time is "right" and the shots are important! I'm just glad it was only 13 shots.