bongo
02-22-2009, 09:36 PM
What is the disadvantage of the non usm version?
ShutterbugJohan
02-24-2009, 01:41 PM
I have the USM version and have never used the non-USM version. The USM with full-time-manual focus is great when not shooting macro subjects (I use MF for closeup shots). As far as I know, the non USM version extends with focusing, which can scare off insects. :-( I've heard that the IQ is pretty much equal.
Jon Ruyle
02-24-2009, 02:09 PM
The disadvantage of non-usm is that it isn't usm. :)
All of canons best af lenses are usm, it is faster and quieter than "conventional" motors for af.
I've never used the non-usm version of the macro, but I would guess that is true in this case, too.
When I was buying, the price difference was modest, so I went with the usm. If I had it to do over again, I would get usm even if the price difference was substantial.