I just got my Canon 70-200mm f/2.8L repaired and the continuous AF performance is better than I ever remember it being. That has me thinking about my standard zoom lens, or lack thereof. I've got a Tamron 28-75mm f/2.8, which has great image quality but the AF speed isn't the best and I think the AF is pretty far off right now. I mainly use it for manual studio product photography now. My other option is my 18-200mm IS zoom - a great all-pupose lens but not up to the same speed or optical standards as the 70-200mm.
So, after having the 70-200mm repaired and finding how good it can actually be, I'm thinking about another L lens - either the 24-700mm f/2.8L or the 24-105mm f/4L IS. And then today I wrote an article about the Sigma 24-70mm f/2.8 and I'm thinking I should take my own advice and consider that lens as well. After all, it's been in our top five most popular lens list for years, I think.
So what do you guys think? Consider that I'm looking for a lens that can keep up with cyclosts and skiers in AI Servo continuous auto focus mode. And price is a factor. I know someone who will sell me the Sigma for $525. That's over half of what either Canon L lens would cost me - a pretty strong motivator. But if it's going to let me down on AF then it's probably not the right thing to do. My recent experience with the Sigma 70-200mm f/2.8 OS HSM has me feeling pretty good about the high-end Sigma lenses. I shot cyclocross with that lens last winter and it was rock solid.
I'd be grateful for any feedback. Thanks