Gave it its first serious use today... and I left myself more confused than when I started. Long story short, initial testing seemed to show focus was good enough, so I just used it. I saw backfocusing in the field but wasn't sure if that just me being too rusty on using the 5D2 or was it due to the lens. Then I noticed the AFMA was set to +17. My guess is this is the value I entered for the Zeiss 50 makro, and as they report themselves as "50mm lens" they ended up sharing the same value. I tried fiddling with it in the field but was getting nowhere.
Now, the above didn't stop me getting shots, although it may be a question of focus reliability. 50mm f/1.4 at close range for wildlife wasn't the best mix, as the DoF was often smaller than the width of the subject's eye...Swan vs. dog
by Crestie Crazy
, on Flickr
Canon 5D mk2, Sigma 50mm f/1.4 A, at f/1.4, 1/5000s, ISO100.
A quick sample for now. This was more distant, and the focus was good enough by luck I have to admit. I did crop this image to better frame it, but if you can figure out flickr's current interface it is 100%. I should also add I just did a quick and dirty process on this, and the 100% view wasn't optimised as it was just an intermediate step to a smaller web view I posted elsewhere.
I need to get bigger ND filters as even on this overcast day I was close to overexposure when wide open.