Whenever I press the function button (Fn), which I have programmed to "preview", it previews the aperature setting ok, but I notice that it locks the exposure too. I've never noticed this before and am curious why it would do that, when you can also program the same button to do just that.
#1. "RE: Why does the preview button lock exposure?" In response to Reply # 0
St Petersburg, RU
The metering/exposure needs to be locked when stopping down the aperture for preview mode, because doing it any other way would require re-metering when the aperture is returned to fully open when the preview button is released. You are ready to take the shot as soon as preview is cleared. Stan St Petersburg Russia