Alex_M said:
Not to sound argumentive, but... at 50mm and f/1.4, say 3m distance to subject, the DoF for a Canon FF camera is 14cm in front and 16cm behind the focus point. Plenty deep enough (in my opinion) for the focus and recompose technique still be usable? Coming closer towards the subject makes the DoF shallow and not as easy to play with, of course, but I usualy shoot tight portrets with a longer lens anyway to avoid perspective distortion...
I guess, with the center being the only usable AF point, 6D users are forced to master their focus and recompose technique.. There is no other option
YuengLinger said:
Once you center focus and recompose at f/1.4, you've lost focus.
Manual focus? Expressions are fleeting, and though my subjects may be "startionary," I don't want them to remain rigid!
We can have a whole other thread about the right focusing screen for manual, and then compromising brightness...We can talk about how many of us can reliably MF now, and how many will still be able to do so in 5 years, 10 years...
But the important fact is that at very shallow DoF, slight movements of a subject, a sway, a tilt or turn, and you have to refocus. With MF, I'd never achieve anything like the keeper rate possible with world-class AF, which is what I get with my 5D3 and Canon lenses. I'd rather my subject be relaxed than concentrating on remaining still.
And by the way, to those who hyperventilate when their brands are challenged, I LOVE my Sigma 35mm 1.4 Art on my 5D3. Fast, reliable AF. The Sigma 50mm 1.4 Art, however, is a lost cause for me, sadly.
Not arguing, but explaining personal use...3 m is about 3/4 body length, and, you are right, at that distance we technically have some wiggle room for "acceptable sharpness" but I would not agree that it is truly 30 cm! I lean more towards peak sharpness when I can get it, though the right expression trumps it when all other factors are equal.
But I like a 50mm in closer for expressive portraits and, especially, for children. Even 35mm has a place for head and shoulder or tighter, but not for yearbook shots or corporate headshots. At 2 m, roughly head and upper body, we are now down to a 13 cm
range of acceptable sharpness. Get in there at 1.5m, down to a 7cm range of acceptable sharpness.
I had to check all this before replying to you, and I'm glad you prompted me put actual measurements to practical application and experience.
But all this, with the Sigma 50mm 1.4 Art, is theoretical irrelevance if it cannot achieve consistent, reliable AF in a variety of lighting situations. And for me, on the 5DIII, two copies of the lens, bought about 16 months apart brand new were all over the AF'ing place, the second worse than the first.
Because of the way I like to use 50mm, I haven't bothered trying an ef 50mm 1.2 L, as I've seen many sample images (not just the 1 out of 500 shot session keepers) and talked with friends who have owned and sold them for slow AF and frustrating focus-shift.
I wanted the Sigma to work. If I read about a new firmware release that specifically addressed the 50mm Art focusing woes on the 5DIII, I'd try it again.
But I still hope for a new version of the 50mm 1.2 L that will focus more quickly than the 85mm 1.2 L II, at least as reliably, and have bokeh as pleasant as the 85mm 1.2 L II or the 135mm 2.0. That's asking for a lot.
