7D : metering problem

Started Jan 13, 2011 | Discussions thread
fpix
OP fpix Regular Member • Posts: 346
Re: Samples shot from tripod (Re: 7D : metering problem)

First thanks to all for interrest and feedback!

Now, one by one:

Brand New wrote:

... Maybe you can try updating to 1.2.3 and seeing if there was a "silent fix" that was thrown in there?

Would be happy to be so. I will install it and give a feedback asap.

akin_t wrote:

Interesting at best, not really a problem per se ...

I mean, if you're consistently getting slightly darker exposures in AI servo, I am going to guess that's how the algorithm works. "Problem" or "bug" is when the camera is doing something it's not supposed to do.
...

Actually this was only a sample to show the problem. First I observed the phenomenon outside with white pelicans on dark lake. This was overexposed! Somehow the same tiny subject in contrast to background, background being large and uniform, but now dark instead of light. I will not produce another sample here but I will verify this assumption anyhow and I guess it will happen as supposed, only the other way around - overexposure. More than this, the phenomenon depends on how large the subject is in frame and on the ratio of contrasts. In normal scenes it does not happen. I know to expose manually using the Zone System, but this another issue. For the moment I am trying to find out if this a bug or if my camera needs service.

balloonchasers wrote:

Maybe the camera is trying to guess where the subject will be moving in AI Servo Mode (since it is in a constant mode of measuring) so it adds a little more weight to the edges of the focus point where as in One Shot mode it measures from the center of the focus point? See what happens if you use a dark background.....
...

Could make sense. I will try to imagine an experiment to check if camera assumes AF point could move away. But it would be silly, in the samples showed camera was on tripod, remote released. Dark background - see above.

balloonchasers wrote:

Also since your sample was taken inside I have to ask if you have encountered this problem outside?
...

I have not tested thorrowly outside, but as mentioned above, I observed the phenomenon outside the first time. And with white subject on dark background, with overexposure. This was worse since I obtained burned whites. So, I guess fluorescent light is not an issue. But I will check.

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