I have always done this in landscape position and using center single point (not spot single)
I almost always take portraits with my 5Dmk3 in portrait position using spot single focus upper right corner to focus on the eye. So my question is why can't I AFMA the lens in that position and focus point? I suppose I could but would the results be different using center single point? Is there a benefit to either way? In specifics this will be for a Canon 85mm 1.2L II lens if that matters
as the AF point is cross type it really shouldn't matter what orientation you shoot in . in fact even if it wasn't I doubt it would matter .
as for spot v normal single point . it may be worth seeing if the MA is different . but you would have to make sure the target has enough contrast in that small area for the AF point to be reliable .
I can understand why you would want to use the spot AF but you have to realise how small an area your dealing with and the likelihood of not getting and contrast in that area for the AF to pick up on . IE the plain white of an eye .
if you can its safer to use normal points .
I also do AFMA tests in landscape orientation and I often shoot my 85/1.2L II in portrait orientation. It works for me.
It should be easy enough to do AFMA for any AF point, assuming the method you use is amenable to this approach. I figure it makes sense to do AFMA tests for the situation that you most often shoot. I use my lenses for all sorts of situations, and so I simply use the centre AF point at 50x focal length (or shorter for 300mm+, because I run out of space in my house).
Don't over-think it. If you're getting good results now, then it's a purely academic question. Of course, there's nothing wrong with pursuing an academic question, if it has high enough priority on your to-do list.
Actually the lens will arrive to me on Monday. I was thinking last night that 95% of the time I shoot portrait and upper right either single point or spot focus for the eye and thought "hey why not AFMA the lens in that focus spot"
gqllc007 wrote:
Actually the lens will arrive to me on Monday. I was thinking last night that 95% of the time I shoot portrait and upper right either single point or spot focus for the eye and thought "hey why not AFMA the lens in that focus spot"
It's an interesting question and I've done a few cursory experiments in the past. What I found is that the peripheral AF points will many times tune to a significantly different AFMA value than the center even though a center-tuned value seems to produce acceptable AF result in the peripheral but not vice versa (using a peripheral-tuned value for the center). Few potential reasons for this - decentered/tilted elements affecting the peripheral points more, higher amounts of lens aberrations away from the center, the AF system actually having logic to counteract these affects and so tuning to the peripheral may defeat that functionality.
Ok so I tried it horizontal center single point and my micro adjust was +1. In vertical upper right single focus point position it was 0. In horizontal it was so close at 0 that I have left it that way
I was using 5Dmk3 and 85mm 1.2L II
gqllc007 wrote:
Ok so I tried it horizontal center single point and my micro adjust was +1. In vertical upper right single focus point position it was 0. In horizontal it was so close at 0 that I have left it that way
The repeatibility for my AFMA tests is +/- 1 EV, at the very best. So for me, AFMA values of 0 and +1 would be effectively the same. I'd use 0 (i.e. no correction) in order to free up AFMA "slots" for other lenses.
gqllc007 wrote:
Ok so I tried it horizontal center single point and my micro adjust was +1. In vertical upper right single focus point position it was 0. In horizontal it was so close at 0 that I have left it that way
I was using 5Dmk3 and 85mm 1.2L II
