>>Is this an opinion or a fact? > >I've certainly seen it stated somewhere. I've just tried it >with my D3s, and there was a difference in indicated >exposure between FX and DX modes when a bright light was >situated in the FX frame corner outside the DX crop area. >This applied using both Matrix and CW metering. > >I guess we won't know for sure with the D800 until someone >tries it out
When you think about it the light entering the lens must be across the full frame? The cropping happens after the light has been captured and the exposure has been set? This seems to be the logical answer. For the light to come through the framed bit only then the area between the inner frame and the outer frame would have to be masked to stop light entering. A cardboard mask cut to the same size of the inner frame and held in front of the lens would prove or disprove it. This is obviously conjecture on my part.