Sigma 100-300/f EX HSM

[burningarrow]

Hi
I just purchased this lens based on the many positive reviews on Fred Miranda's site. Although it's equiped with HSM I don't find the AF as snappy and quick as I'd like it to be. I'm comparing this to the AF speed of for instance the 135L, 70-200 and other L lenses.
Does anyone who has this lens have the same experience?
It's a pity though because other than that it's pretty sharp and I like the range.
I need it for tracking birds in flight and sports (soccer, car racing). Any other recommendations?


Thanks
Matt

PS I use it on a 1DM2

[condyk]

Well you're comparing to a short prime and one of the fastest AF's you can buy in a zoom. The 100-300mm f4 is a stellar lens and perfectly capable of focusing fast. I always found my ex copy extremely fast, certainly faster than the 100-400 IS L I replaced it with (no better IQ but I needed the IS).