a jeste se ted divam na recenzi toho objektivu na photozone:

The AF speed is pretty good and the noise level during operations remains on a very low level. Unfortunately the test camera (EOS 350D) didn't really like the lens. At 55mm it had big troubles to lock on reliably and in the field things weren't all that convincing beyond either. This aspect is much better on an 40D or 400D though.