Unusual Exposure With The D200

[Speed]

I took photo's at my daughter's soccer game Sunday afternoon, and when I downloaded them, I got quite a surprise. Two of the images were under-exposed, so I'm thinking really high shutter speed, BUT, they were blurred, indicating a slow shutter speed.

I was shooting my D200 in apeture priority mode, and I was using my Nikkor 80-200mm f2.8 set at f4, and ISO 100. The EXIF data shows that my exposures varied from 1/320th second to 1/800 second. Except for the two images. They showed 1/40th of a second and f 0. Yes, zero.

Has anyone ever encountered this before? Any ideas what happened?

Here's one of the photo's - which turned out great IMHO. I lightened it up using levels and resized it for PR.

[deckcadet]

I'm guessing that the 80-200 was being used via the command dials?

I know precisely what happened.

Your lens lost electronic contact with the camera. This happens one of two ways, if it resumes normal shooting afterwards:

1) the CPU contacts on either camera or lens were dirty and lost signal
2) you accidentally hit the lens release button and the lens twisted a bit and the CPU contacts lost contact.

Either way the result was the same. Since the 80-200 is a CPU lens, you generally lock the aperture ring at minimum aperture for command dial control. upon lens release or cpu contact loss, the camera treats it as a non-cpu lens, which must have its aperture set via the aperture ring. In this case, while the camera holds the lens wide open (or nearly so if you accidentally hit the lens release) and then drops the stop down lever all the way, allowing the lens to fall to wherever the aperture ring is set. When there is a non cpu lens or any other lens with an aperture ring, this is where the ring is set- it won't close down further than f/8.0 if you set the ring accordingly.

In your case, since it was at minimum aperture, it dropped it all the way to f/22 or 32 or whatever.
This would account for the 3-5 stops change in shutter speed, and even then the severe underexposure encountered.

[Speed]

Thanks Harrison,

I thought that maybe I had hit the DOF preview button, but at f 4, that wouldn't have made a difference. The thougth also occurred to me that I may have hit the lens release button (causing loss of contact with the CPU contacts). I seriously doubt the lens came loose and rotated, even slightly. You own several big lenses, so you know that when one of them moves, you know it. I just can't conceive of that 80-200mm rotating and I wasn't aware of it.

Dirty or loose CPU contacts occurred to me as the most likely cause. But I've never experienced anything like this before, and I was real curious if anyone else had.

Thanks for the comments. I will be checking and cleaning my CPU contacts tonight!

[another view]

I have that lens and it's not the tightest fit on a few different bodies compared to other lenses. I've never had this problem, but how much movement would it take to lose contact? I'm guessing it has to move at least several degrees for the aperture to close down though, and it would be a surprise that the lens didn't fall off in that case! Nice shot though.

Two of the images were under-exposed, so I'm thinking really high shutter speed

But - you were in an auto mode so shutter speed affects aperture directly, so this wouldn't do it. Now that we know what happened, I suppose the camera got as confused by the f0 as I was when I saw it...

[deckcadet]

I have that lens and it's not the tightest fit on a few different bodies compared to other lenses. I've never had this problem, but how much movement would it take to lose contact? I'm guessing it has to move at least several degrees for the aperture to close down though, and it would be a surprise that the lens didn't fall off in that case! Nice shot though.



But - you were in an auto mode so shutter speed affects aperture directly, so this wouldn't do it. Now that we know what happened, I suppose the camera got as confused by the f0 as I was when I saw it...

It doesn't take a whole lot to lose contact, particularly if your contacts are dirty.
All it will take is this loss of contact to result in full stop-down if you are using the lens via command dials.

The F0 is just its way of saying that it detects no CPU lens attached and no non-CPU lens data has been entered.

[Speed]

"I have that lens and it's not the tightest fit on a few different bodies compared to other lenses."

Hey Steve,

I know what you mean about the lens not being the tightest fit. There is a slight bit of movement on my F5 and on the D200. Ironically, it fits the tightest on my N80!

"I've never had this problem, but how much movement would it take to lose contact? I'm guessing it has to move at least several degrees for the aperture to close down though, and it would be a surprise that the lens didn't fall off in that case!"

My thoughts exactly. That's a fairly big lens, and if it moves, you should know it!

"Nice shot though."

Thank you. I am pleased with the overall effect. This is undoubtedly the best of panning I've ever done. I guess shooting sports for several years now has honed my panning skills somewhat.

"But - you were in an auto mode so shutter speed affects aperture directly, so this wouldn't do it. Now that we know what happened, I suppose the camera got as confused by the f0 as I was when I saw it..."

I shoot in Apeture Priority about 98% of the time, and that's what mode I was in when I shot this. It's what I'm comfortable with. But I think Harrison nailed it with the dirty CPU contacts. The lens and the camera weren't "talking", and this was the result. And yeah, that f 0 thing is a mind boggler.

[Speed]

It doesn't take a whole lot to lose contact, particularly if your contacts are dirty.
All it will take is this loss of contact to result in full stop-down if you are using the lens via command dials.

The F0 is just its way of saying that it detects no CPU lens attached and no non-CPU lens data has been entered.

I forgot to mention, but you were right - I use the command dials to set the apeture. I cleaned the CPU contacts on the lens and the camera last night. While I couldn't tell how dirty they were, there was a fair amount of build up on the mounting ring. So I think you nailed it buddy - dirty CPU contacts!

Thanks again buddy!