I have a lens that I absolutely love for many of it’s qualities, but at least with our 7D when wide open it consistently misses focus by just a bit. But enough so that when shooting stacked photos of our dogs (i.e. standing in a certain way to show the structure) the dog is just barely out of focus. The ground immediately in front of the dog however is tack sharp for 20cm or soâ€¦
The lens in question is a Sigma 150/2.8 EX APO MACRO DG HSM. I really like the lens and the way it has a very shallow depth of field when wide open. But, like I said most pictures taken when wide open tend to be a tad front focusing. So while I’m not interested in the least in shooting test shots of lens charts etc. I decided to follow the microadjustment tricks by Arash Hazeghi on a bird photography forum.
After some time clicking away at the focus and generally fiddling around, based on some quick tests I dare say focusing has improved. By how much remains to be seen since it is too cloudy outside to attempt any kind of pictures of even a standing flatboat â€“ they never stand entirely still and motion blur will destroy any attempt at evaluating sharpness ;)
Just as a note, when the subject is 7.5 metres away from the camera, with a 150mm lens on a 7D opened up to f/2.8 the depth of field is only 27 cm so the margin of error isn’t very large.
And although I wasn’t planning to, I did grab a few test shots while our grill was heating up.
At least based these quick tests, the focusing is better and spot on where I wanted it to be. Admittedly I did misfocus quite a few shots, but 150mm and a close subject means that even the slightest shake of my hand is quite large. And the flames and smoke between the lens and firewood didn’t help either.