Hi all
On pg 236 of the D7100 manual there an option described as C1, which, if I read it right, would enable exposure to be locked in once you half-press the shutter button. Meaning you don't have to keep it half pressed after that and as you recompose, given it's the first reading you really want to keep. This seems like it might be helpful if, for example, you were metering for exposure off a neutral tone in the sky then swinging down to compose your shot where the background lighting was so bright it would then cause underexposure.. I'd be interested to know if anyone has got some experience using this custom setting..and if I am interpreting what the setting will do correctly.