[Rover]

The Canon 85mm f1.2 L USM has (very) noticable DOF difference to the Sigma 85mm f1.4, even in above comparison. The Sigma 85mm f1.4 gives more or less comparable DOF results at f1.4 to the Canon 85mm f1.8 USM at f1.8.

 

Scroll down to the up close wall corner sample here, to see the difference with f1.2 to f1.8 on the 85mm f1.2, and the difference between the 85mm f1.2 at f1.2 to the Sigma 85mm f1.4 at f1.4:

http://cannonfastreviews.com/canon-85mm-...m-f1-4-ex/

 

Whether the difference is important to you as photographer, that is personal. But the difference is clear and there....

For more light, one should not bother. As most of the extra light gets lost at micro lens level anyway. Same is true for f1.4 vs f1.8, by the way.

No, I meant f/1.2 vs f/1.4 vs. f/1.8 on the same lens. Sigma is apparently a bit shorter, hence the difference - which still doesn't look nearly important enough for me. I might get the Sigma someday though (I know I want one).