What do you mean, it’s out of focus again?!
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 so…
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 – 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.