Hi all, I am using back button focusing on my d7100 and just noticed the custom option (pg 236 in the manual) which seems to make it possible to just half-press the shutter button once to lock in exposure. So seems to me that, shooting a sunset for example, you could read your exposure setting from a more neutral tone in the sky by half=pressing the shutter button once, then recompose on a brighter part of the scene without keeping your finger on the shutter button the whole time. Do I have that right? And has anyone used the option in combination with back button focusing?
The C1 setting is determining whether or not the exposure changes as you hold down the shutter button and recompose.
Really, the best way to understand this is to try it. With C1 On, frame a bright area, recompose to a darker area while holding the button, then fully depress the button to take the shot. Do the same thing again with C1 Off. The difference will become apparent.