Suppose I have my D800E set to center-weighted metering and the center metering circle set to 20mm. If I mount a DX format lens and the camera automatically switches to DX format, does the center metering circle remain at 20mm, or does it shrink to a size appropriate to the DX format?
I could not find anything on this in the owners manual.
#1. "RE: D800E Center-Weighted Metering in DX Format" In response to Reply # 0
The camera will remain at whatever metering circle size you designate regardless of mode. That does represent a larger portion of the image in DX mode than FX mode. The menu - and the camera - do not differentiate based on lens choice or lens mode.
Your question got me thinking about matrix metering. I have not seen anything definitive, but I expect that Matrix metering also does not change - even if part of the image is outside of the DX boundaries.
#2. "RE: D800E Center-Weighted Metering in DX Format" In response to Reply # 1
Light falloff around the edge of the FX frame can be observed with some DX lenses. If brightness levels over the entire FX frame are used in the exposure calculation (in either matrix or center-weighted), then it seems that the light falloff would be a source of metering inaccuracy with DX lenses on an FX camera.
I have not thought about this question before and have not used a DX lens on my D800E. It may be that the effect on the overall exposure is not enough to matter.