[deejjjaaaa]

This is a good point. Most lenses are sharpest (and will have most contrast) in the center, and will have relatively soft borders wide open. Relying on other AF points here may not help the situation.

where did you see anybody talking about other AF points ? central and only central AF point... I even do not recall more than one or two posting when people were mentioning FF/BF @ others sensors.

[Kerrowdown]

On the odd occasion when you're in a really low light situation, remember you can always switch over to manual focus, we do have the best of both worlds here.

[Russell-Evans]

This will have no affect. Focusing and metering is always done at max aperture, the lens only stops down just before and during exposure.

OK, I see the mechanics of it now. I thought the ring forced a set position and it couldn't be opened further. I see now, after reading your post, that the arm in the mount forces the aperture open to its maximum diameter.

Thank you
Russell