Focus shift. And people who say it doesn't have it just never trigger the "sweet spot" for this phenomenon, not that there's something wrong with that (not hitting it). But all lenses have it - it's a "feature" of the optical design, and has nothing to do with bad alignment.
I have MA calibrated my 50L for f2 @ 3m, since that's how I shoot it most of the time. Of course that means that anything wider open is front focused, but I pretty much always shoot at f2 because I can't stand the look of the 50L wide open.
Set camera on tripod
Enter live view
Set Av f2.0
Focus on something focus worthy about 5 feet away (using live view)
Take picture
Take same picture at f1.2
Compare focal planes
Come report back
Jun 22, 2010 at 02:57 PM
Lars Johnsson Offline • • • • • • • Upload & Sell: Off
