Hi,
I recently tested the 85mm F1.2 (both Mark 1 and 2) on my friend's 5D Mark2. This lens is very difficult to use even in moderate indoor low light condition wide open. The pics done with this camera is constantly out of focus unless the person literally holds still.
The result is consistent with my older 20D when I use the lens in my friends wedding and many precious moments are ruined. These photos are done in one shot mode using the centre focusing point.
I wonder if the 1D mark3 is able to tame this beast and allow the lens to manifest its potential at full aperture without using flash.
Could anyone help to comment?
Problem is not the lens there. Its a very specialized lens not meant for the faint hearted. Wide open at f/1.2, at under 2m distance, your DOF from the lens is around a few millimeter. The normal focus and compose method will not cut it as there is so little margin on the DOF. Which is why you have loads of OOF shots.
You'll be better off with shoot and crop instead if you're not confident of nailing the focus.