Yes, you'll pay a bit extra just for the Canon name. But you're also paying extra for the higher quality build, the superior construction materials, and the better quality optics. Read some reviews of the lenses you're interested in; I'll bet most reviews favor the Canon and that the objectively comparable points - lens resolution, contrast, noise level, etc. - all at least somewhat favor the Canon.
You have to decide for yourself whether the improvements in those features are worth the extra cost to you. An expensive lens may make a great shot somewhat better, but it won't make a mediocre shot good, let alone great.
Having said that, I also suspect that if you shoot seriously for any length of time, you'll eventually see the difference in optical quality and would come to prefer (or wish for, depending on your current decision) the Canon lens. I know that my old Pentax lenses yield sharper, crisper, "better" pictures than the various off-brands I've tried. After several "bargins, I started buying only Pentax primes. Best choice I ever made.
But, then again, I'm no expert and Pentax A and M primes cost about the same as the Sigmas you're talking about, not the Canon prices.
In all fairness, my answer is tainted by the fact that I just bought an $80 Black & Decker plunge router - and am already wishing I'd waited to buy a $200 Porter Cable. Still learning, I guess.
|