sorry but may i know why 17-55 instead of sigma 17-50? since 17-55 second hand and a sigma 17-50 cost around the same and sigma still has the warranty?
The main reason being focusing speed and focus consistency/accuracy. (I have only tested my friend's 17-55 about a week)
focusing speed - Canon's USM is faster than Sigma's HSM, not faster by alot but noticeable.
focus consistency/accuracy - Under quite extreme low light (imagine a subject lit by only a single distant street lamp), Canon's focusing is more reliable than Sigma. Thou I don't shoot alot under these conditions, but it's irritating when you encounter such situation. When I do encounter these situation, it's during casual events like BBQ where lighting can be very poor.
Some other "non-critical" reasons, I kinda prefer Canon's color over Sigma's color... Thou I do know many who would say otherwise. But this is my preference lar. It's non critical to me, as colors can be adjusted during PP provided that you spend the time (sometimes alot of time) to adjust it to your liking.
Warranty - ya, this is one of those things I got cared about about too when I got my Sigma 17-50. But please do note that if your lens by any chance needs servicing, please be prepared to take leave to go down SSC (
Sigma Singapore • Contact), since they only open on Weekdays (Mon-Fri 9am-6pm). CSC at least opens 1/2 day on Saturday...
If you are getting a grey set or 2nd hand, there's always a risk factor. So, you will have to make the call to see if compromise is worth the amount difference. So what I'm talking about is: lens performance vs cost vs warranty service. Balance it out and you will know which one is more suitable for you.
But, since I've already bought the Sigma 17-50, I have no wish to get the 17-55, since it's still quite a good lens, but IMO just not as good as the Canon's one (In short "You get what you pay for"), but I can live with the above mentioned "defects" since, those are not really the limiting factor of the outcome of the shot.
