D7100 exposure accuracy?

Started Mar 4, 2014 | Discussions thread
Mako2011 MOD
Forum ProPosts: 17,811
In reply to Mystery Guy, Mar 5, 2014

Mystery Guy wrote:

Mako2011 wrote:

Mystery Guy wrote:

For example, with my 35mm 1.8G, if I start out using Manual mode and F22 (say at 1/6s) to set the exposure, and then just work up through the F-stops keeping the matching exposure (next F16 @ 1/13s, etc.),

f22 and 1/6s is 1/3 stop different from f16 1/13s

the actual results I'm getting seems to be as much as 1 F-stop different across the entire range (between lightest and darkest pictures).

So minor miscalculation might be part of it

So, just trying to take the same image with the same lighting would give a variation based on what F-stop was actually used (even though the camera meter always seemed to say that exposure was 'correct'.).

What increments is your meter set in?

It's currently set to 1/3 stop increments (the default I believe). Maybe what I'm seeing is a metering issue.

That's what I have mine set to as well...but I know it's not as precise as say the histogram but certainly gets as well in the ball park as +/- 1/3 is no biggie in post (as long as I don't clip something I want to keep).

For whatever reason, I often see variations where manually adding +0.7 exposure compensation makes things look better to me (in just general picture taking).

Nothing wrong with that. Many add a global correction and it simply works. Ray Soares always set a -2/6 EV in his setup and I don't...And I honestly think our cameras were metering identically. There's, IMO, some honest subjectivity to what's the correct exposure.

I don't know if the following is an expected difference or not, but I quickly took the following two pictures under the same light using Aperture priority and Matrix Metering.

These are indeed different and the same exposure. You didn't use liveview did you? You don't happen to have ADL set to "on" do you? That can account for some of the dif.

The F22 one seems a shade darker, and if I open the .NEF in Adobe Camera Raw and increase the exposure by 0.7, the two images look a lot closer to each other to me (and have a more similar histogram).

Open in ViewNX2 and see if the look just as different. Looks to me more like maybe the aperture isn't exactly f22 but way off....might be a simple lens issue. In this case it would be less than 1/8 of a stop if f22 was really f23. And still way small if f2.8 was really f2.6...so if an aperture issue it would have to be a big one.

I understand they shouldn't look exactly the same (they are at two very different apertures), but I was hoping that the apparent brightness would be closer. Maybe you can tell me if this is considered an expected amount of variation or not.

I wonder if this might be ...long shot...an ACR issue with the brightness instruction set. Do you get same result shooting JPEG?




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