The first problem lens is a 50mm 1.4. It is the type that can be focused manually at the same time as AF operation. The front lens barrel moves in and out during focusing. On this particular lens, the barrel will move no closer than about 3 ft. focus. It's possible to push on the barrel while turning the ring and get it to move a little farther, but only at the risk of getting it stuck (and probably damaging it more). I don't know how it happened; I just noticed the problem one day when I took it out of my bag. Is there anything I can do for the lens, or should I send it back to Canon? I'm not sure if this lens has a valid warranty or not.

The second lens is the 75-300 4.0-5.6 image stabilized. It uses the geared type motor with a rotating front barrel. It will grind horribly if you rotate the barrel manually in AF mode. This has unfortunatley occured a few times when attaching the hood, as it is a tight fit and must be rotated into place (these days, I remember to put the lens in MF before attaching the hood). The lens no longer focuses accurately in AF mode. Objects in the focus area are always slightly out of focus, although MF still works normally. I have verified this problem on two working EOS bodies, both of which focus inaccurately only with this lens. Is it likely that the problem was caused by the gear grinding? If so, I guess Canon won't cover it.

Any ideas or information about the above two problems would be greatly appreciated.

-- Damon Taibi (phlegmat@hotmail.com), February 28, 2001

Answers

It sounds as though you may have damaged your 75-300 while putting on your lens hood. Do you use a hood on the 50 1.4? Nonetheless, I would seriously consider NOT playing with the lenses: pushing pulling turning, etc. Send them to Canon and get them checked out.

-- Roger Shrader (rashrader@hotmail.com), February 28, 2001.