I own a 200/2.8 L II USM. Bought it used in 2008, in great condition. I've used it a lot over the years. Always carried in a well-padded bag, never dropped or handled roughly.
It worked normally as late as a few months ago, when I last used it before this week. Suddenly, it refuses to focus to infinity using autofocus. It gets nearly there, up to maybe 500 ft, but farther objects than that just won't get into focus. The shutter won't release (since I have focus priority over shutter release). However, if I manually nudge the focus ring the last bit, focus is achieved and the shutter will release. Manual focus works normally, at all ranges, so it's not an optical issue.
I've tested on two camera bodies, a 77D and a 90D, with exactly the same behavior on both. I've also tried both through-viewfinder AF and live view AF, and the problem is present and identical in both situations.
Yesterday, I was briefly able to get it working by flicking the focus limiting switch between the two positions (the 200/2.8 L II USM has a switch that limits the close end of the AF range to 3.5 m distance instead of the optical close focus distance of 1.5 m, but neither setting affects focus at infinity). I thought the problem was solved then, but the issue is back today.
It's obviously a problem with the lens itself, since all other lenses work fine, and the problem is present on two different camera bodies. And since I can manually focus to infinity, it's not an optical problem. Nothing is loose or visibly damaged. The golden contacts at the lens mount all look pristine, with no dirt or corrosion. The AF works normally at all distances shorter than about 500-800 ft. Fast, accurate and repeatable.
Any ideas? I really love this lens, so if this is an issue that can be fixed, I'd be thrilled.
