Autofocus matters!

[tomah]

I've narrowed down my next lens to either:

i) Canon 17-55mm f2.8 IS USM
ii) Sigma 17-50mm f2.8 EX DC OS HSM (what a mouthful!)

Now, I appreciate the Sigma is a very good lens. That much appears very clear from reviews and various threads.

But, I'm not just after IQ. I have a two-year-old, and another child on the way, and kids move randomly and quickly. In fact, many potentially good shots are lost when using our nifty fifty because of it's rough AF.

The question is, is the Canon noticeably faster than the Sigma? I know the Sigma has HSM, but is it comparable to Canon's USM, or will I be frustrated by it?

I'm not a brand snob, so I don't mind owning a Sigma. I've owned a couple in the past.

I just wonder if I should buy a used Canon, or a new Sigma!

Please don't respond telling me the Sigma is good and very sharp. I know that. This is more to do with AF. I need it to be faster than my daughter! :bonk:

 

[The23rdman]

Speed may not be much difference, but accuracy may. Take your body to a shop and try both. It's really the only way to tell.

None of the Sigma lenses I've owned or used have been as accurate as the canon or Nikon ones.

 

[scottthehat]

as said by dean, go try before you buy. only had one sigma duff lens, but my others have been spot on and my 50-500mm os is my fav lens over all my nikon lenses.

 

[tomah]

It's really hard to ignore the 4 year warranty on the Sigma, compared with no warranty on a used Canon.

I only wish I could get into the classifieds here to see if there's a used Sigma. I could potentially save even more and make the decision a no-brainer.

 

[LongLensPhotography]

Canon holds value better, just in case you had to sell later.