Good detective work Moose. Jim, if the problem is an intermittent but
regular occurence, why not just keep taking pictures of the same scene
until it happens, perhaps even using a tripod. You may need to try
different camera settings and differently lit scenes to provoke the
problem, but as long as you have a good exposure along with the bad
with certainty that no settings were changed between the two, you will
have the answer to whether the problem is with the camera (and / or
lens) or not. With digital it won't cost you anything.
James
On 10 Jul 2004, at 9:37 am, Moose wrote:
> Lots of interesting posts on this, much info.
>
> But lets get down to it.
>
> In 366, in spite of being given orders to overexpose slightly and
> having
> a large expanse of bright sky, the camera did an excellent job of
> exposing for the main subject.
>
> In 367, it badly underexposes a really ordinary scene. There is only
> one
> sensible conclusion. Something in not working properly. Ruminations
> about matrix aside, I can't believe that any modern exposure system
> could miss this badly. This is just not an exotic lighting situation.
>
> So what could be wrong?
>
> Lens? You say a N*** zoom, I assume the same for each pic. EXIF
> contains
> focal length, maximum available f-stop and exposure f-stop. So it would
> appear to be a proper lens for the camera, at least it communicates
> with
> it. Both shots were at f5.6. So it doesn't seem likely that it is the
> lens, but the lens is older than the camera. Confirmation through uae
> of
> another lens and/or results with this lens on another camera would
> confirm.
>
> Camera? There are a couple of clues in the EXIF.
> #366: Exposure Time 1/60 , F-stop f5.6, Exposure Program Aperture
> priority - Flash undefined value
> #367: Exposure Time 1/250, F-stop f5.6, Exposure Program Manual - Flash
> did not fire
>
> So in the same light, but without a lot of bright sky in the background
> and at the same aperture, the camera selects a shutter speed 2 stops
> faster! Now why would it do that?
>
> - Well, the EXIF says it didn't! It says it was under Manual control
> for
> the poor exposure. So either you changed the setting, perhaps
> inadvertently, or the camera does so on it's own and needs repair.
>
> - Because the exposure system knew flash would be needed? Notice that
> in
> the Flash section of the EXIF for 366 says 'undefined value', while in
> 367, it says 'did not fire' That sounds to me like it was expected or
> needed to fire but didn't. Now you say it was set for no flash. So it
> is
> possible that the 'did not fire' is a comment that flash was needed,
> but
> not selected. Of course the flash sync is only rated to 1/180 on the
> D100, so a manually selected speed of 1/250 probably prevents the flash
> from firing anyway.
>
> So what can be concluded from the samples? It is possible that there is
> something wrong with the camera, but that can't be concluded from these
> samples. Further careful testing is required to be sure whether the
> change of mode from AP to Manual was an external or an internal event.
> If external, it appears the camera did as instructed; it took an
> underexposed picture. I doubt if these pics will convince Nikon Service
> there is a problem, if they read the EXIFs, without further clarity on
> settings.
>
> Moose
>
> *Also, what kind of camera doesn't show the iso setting in the EXIF??
>
>
>
>
> Jim Sharp wrote:
>
>> Nope, I was set to auto focus and for no flash, using a Nikkor zoom
>> borrowed from my SO.
>>
>> As this conversation has progressed I'm wondering more all the time if
>> my camera doesn't need a trip to Nikon service. Now that I've
>> identified
>> some good example photos at least I have something to point them to
>> that's better than "I think my camera's metering is broken..."
>>
>>
>
>
>
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