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Nikon D7100 and automatic exposure compensation
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PostPosted: Sun Oct 15, 2017 5:52 pm    Post subject: Nikon D7100 and automatic exposure compensation Reply with quote

Hi all

I was teaching someone with a D7100 about light metering. I asked her to make a photo, using A, of a white sheet and one of a black sheet. I wanted to show her how the camera's light meter would make two identical shots, i.e. 18% grey.

However, unexpectedly, the camera made a perfectly white photo and a perfectly black photo. It had automatically chosen an exposure compensation of +3 and -5. I tried it myself, making sure the exposure compensation was set to 0 and exactly the same thing happened.

I am puzzled as to how this can happen and also very curious to discover a new function I didn't know about….

Anybody?

Thanks in advance!


PostPosted: Sun Oct 15, 2017 7:30 pm    Post subject: Reply with quote

How is it known exposure compensation was made (other than results!)?

I think white balance is effective rather than exposure compensation. Try in fully manual mode?


PostPosted: Sun Oct 15, 2017 7:33 pm    Post subject: Reply with quote

Thanks for your help!

It shows in the exif. There's a +3 for the white photo and a -5 for the black photo. Although the exposure compensation was set for both shots to 0.


PostPosted: Sun Oct 15, 2017 7:59 pm    Post subject: Reply with quote

What was camera mode? Not fully manual, I think. Setting exposure in full manual mode should give expected results.


PostPosted: Sun Oct 15, 2017 8:10 pm    Post subject: Reply with quote

Indeed, it was set to A (Aperture) mode.

In this mode the shutter speed is chosen by the camera to expose an image to 18% grey. Hence the photo of the black paper and the photo of the white paper should both be 18% grey.

However, on this particular D7100 they were not. The 'black' photo had automatically underexposed and you can see that in the exif. It says -5. The 'white' photo had automatically overexposed and the exif say +3.

This is the first time I see this and I have had pupils doing this exercise with a D7100 before.


PostPosted: Sun Oct 15, 2017 8:22 pm    Post subject: Reply with quote

A priority is not what I'm calling full manual.

This sounds now like a feature. I guess comparing firmware version numbers between a 7100 that operates as you expect and this one. Other than that perhaps someone here with that model can tell us what menu setting causes the auto exposure to kick in...


PostPosted: Sun Oct 15, 2017 8:26 pm    Post subject: Reply with quote

With 'indeed' I meant: you are right, NOT fully manual Wink

I will look into the firmware thing, that's an interesting lead.

And yes, I'm also suspecting some setting that I'm unaware of and that I can't find back in the manual or anywhere online.

Thanks for your help!


PostPosted: Mon Oct 16, 2017 4:18 pm    Post subject: Reply with quote

I am hoping someone on this forum owning a D7100 will come up with an explanation of this 'phenomenon' if I may call it that. Looking forward to your responses!