nikon d800

[david distefano]

i have had the d800 for 1 1/2 years, but this past sunday something strange happened. i was using the 16-35 f4 lens, the sky was sunlite and no clouds. i was required to take pictures of my grandson at the pumpkin patch. camera was as usual set at ap. priority iso 100. the problem was that every shot and i mean every shot had to be retaken because the captured image light level would change dramatically from under to over exposure. i normally take a shot under the conditions i am going to work under than make any +/- adjustments and go to work. nothing worked. every shot was different under the same lighting conditions. no shots were taken into the sun. as i said this has never happened before. any ideas what is going on. yes i just tried it today outside and the same thing happened, but when i tried shooting in shaded areas, no problem.

[BenMm]

1. Did you inadvertently turn on exposure bracketing?
2. Is the meter set to "spot"?
3. Try another lens in case the one you are using has a sticky aperture.

[Telecaster]

The first thing I'd do is put the camera in manual exposure mode and take a number of photos of the same thing with the same settings. Are the exposures consistent? If so try the same method with both brighter and darker subject matter. Again consistent? If consistent are the exposures in line with what you'd normally expect given the settings you're using? If all seems well maybe the camera's autoexposure system is glitching. But if you're getting differing exposures from the same settings in the same conditions...could be a shutter issue, could be an aperture control issue, could be a sensor or processing issue. Does this happen with other lenses?

-Dave-

[jgcox]

Any chance it's a sticky aperture? Maybe try a different lens?

[TMARK]

I vote for the lens aperture, either the camera isn't stopping down consistently or the aperture is sticking.  I doubt its the shutter, as the failure mode is usually different.  I've never seen a meter failure in a DSLR, not that its impossible, but I've never seen it.  In fact, I haven't seen a Nikon or Canon meter failure since they moved away from the simple needle solenium cells of the FM/FE/F1.

[david distefano]

i just went outside again and changed f stops and except for f4 (wide open) every other f stop was dead on. so i guess something is sticking at f4.