mrtobin wrote:
I'm sorry, but your "test" makes no sense. How can you test a lens in complete darkness with the iso cranked up and the shutter opened for a prolonged time? It seems to me this will just show sensor noise, and what would you expect when heating your sensor up in with this "test".
Do the same "test" with the lens off and you will probably get similar results.
Or, maybe I just read your post wrong and do not under stand what you are trying to do.
Ok, Ill explain it again.
This is a known issue..Nikon acknowledges it. They said they can improve it, but cant fix it altogether, and offered me a couple options. I dont have a lot of confidence in Nikons repair dept as I had problems with them in the past. Granted, I dont shoot that long of exposures very often at high iso, but if I wanted to shoot the milky way, or a night landscape and didnt want star trails, I may need the high iso, and since the problem appears at 30 seconds, and you would need high iso to get results desired in described situation, there would be a red glow on the rhs of the image.
Tests I did is just the way to see if the lens has the issue. Google it and you will see Im not the only one with it.
I thought I detailed it enough, but at 16mm under conditions described a red glow appears on the rhs and top of the frame. It begins to show up at iso 5000, 30 seconds, and gets brighter as exposure gets longer. I did multiple shots starting at iso 800-5000. And at longer exposures it shows up at lower iso.
At 35mm it barely shows at iso 5000, 2 minutes, at 16mm its very obvious at iso 5000 1 minute, shows at 30 sec. It becomes noticable at iso 2000. If it were a sensor thing it wouldnt make any difference what focal length was used. It would also most likely show the red coloration across the whole frame and not just the rhs.
BUT...to rule out the sensor I did the same identical tests with my Nikkor 24-70/f2.8. No problem with that one. ISO 5000 for 3+ minutes produces no glow...solid black frame, as it should be. So, the ISSUE IS WITH THE LENS. One difference between the two lens's is the 16-35 has vibration reduction, altho I tested it with vr OFF, lenr ON. Also if you bring up the exposure in the raw file a little it shows 3 distinct intersecting "arcs" within the area in question.
When D800 sensor gets hot you will see "hot pixels"...they could be mistaken for stars since they look like little points of light. Its much more apparent with lenr off. This occurs often when shooting frames to make night time panoramas with lenr off since you're shooting one longer exposure (20-30 sec) after another, even at iso 100. common issue with any dslr.