Originally posted by ryno It's always possible that someone has a bad copy of a lens, or a malfunctioning camera, but people seem very quick to post problems. There was a long thread on "another" forum about how the 17-70 was soft at infinity at the tele end. I'm not much of a tester, but when I got mine last week, I wanted to make sure there were no problems. To make it easier, I set the camera to manual focus with the ring at infinity and did an aperture series. Like the other review, mine was soft at 70mm until f11. I retested today using auto focus, and f4 was slightly soft, but everything else was perfect. Almost like manual focus focused past infinity. Maybe the other review used manual focus too, but they posted the photos without checking things out. It's easy to bad mouth good equipment, and people tend to believe what they read.
Ryan
How exactly did you perform the test? With a collimator?
If it does focus past infinity, then it wouldn't be the first lens to do so. Here's a comment from the Canon EF 17-40 f/4L USM manual:
" To compensate for shifting of the infinity focus point that results from changes in temperature, you can rotate the distance scale slightly past the normal infinity focus mark.
* The infinity position at normal temperature is the point at which the vertical line of the [graphic] mark is aligned with the distance indicator on the distance scale.
* For accurate manual focusing on subjects at infinity distance, look through the viewfinder while rotating the focusing ring. "
BTW, the problem with the digitalcamerareview reviews was the reviewer. He couldn't manage to take a sharp shot with either the DA* 300 or the DA 17-70. Also, raw files are always relatively soft because of the way sensors (other than the foveon ones) are made.