Got an MFA question. How far off is too far? My brand new 85 f1.8 was simply not hitting the focus point. Last night at an awards ceremony I had to switch to the 135L and stand in the back of the room. The images from the 85 weren't even looking sharp on the LCD, so I knew they'd be crap on the laptop. Today I set up a jerry-rigged MFA session in our hotel room and managed to dial in the 85 to what seems to be a sharp focus. But it's an adjustment of -6. Is that acceptable (assuming it really is now hitting focus)? Or should I send it in to Canon for calibration?