Originally posted by fa8362 No, "M" lenses stay wide open during exposure unless you use the green button. "A" lenses stop down, but "M" lenses require green button use. I have two "M" lenses and if I don't use the green button, the aperture opens fully during exposure, regardless of aperture setting.
Well, with my M lenses, I use Manual exposure mode. Let's say I set the shutter speed to 1/60th. Then I set my aperture to f8 and press the green button. It resets the shutter speed after stopping down, say, to 1/15th. Then I press the shutter button. The exposure is correct, so the lens must have stopped down at some point. Are you saying the green button locks the aperture down?
I do realize that in AV mode, the aperture does not stop down regardless of what the aperture ring is set to. I only use M mode.