I got a real newbie question: if I'm in manual mode for aperture/shutter and have auto-focus on, and I step down the aperture the view finder gets darker (I assume I managed to turn on some preview) and I don't see anything of what's in the frame - which of course is a problem (this is in a studio setting with flashes). I can't figure out how to turn off this "preview mode" so I can see what I'm trying to take a photo on.
Can anyone give me a hint how to turn this off?