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p.1 #7 · p.1 #7 · I've outgrown my Sigma 17-50. Suggestions for replacement. | |
johnctharp wrote:
Is your 17-50/2.8 the OS version or non-OS version?
The original, non-OS version was known to be softer than the current OS version (people went with Tamron for a fast sharp crop standard zoom).
The non-OS is the 2.8/18-50 (EX), the new one with OS is a 2.8/17-50.
I used the 2.8/18-50EX for several years on 300D and 450D and indeed it is soft wide open especially in the borders/corners, mostly due to field curvature for infinity scenes. And AF wasn't very reliable on some Canon bodies. You need to stop down the non-OS version 2-3 stops for really sharp corners at infinity; the Sigma 17-70 lenses from that period had similar issues. But once stopped down it was an excellent lens, better contrast and color than the Canon 18-55IS kit zoom and much better mechanical quality.
The new 17-50 OS version is known to be a bit soft wide open, but most reviews say it is already excellent even in the corners at f/4. The Canon 2.8/17-55 is probably better full open, but that's the only advantage it has. The Sigma has better build and is a bit smaller/lighter as well.
I considered the 2.8/17-50OS but after reading the tests decided to keep my 15-85IS; stopped down they are probably pretty close in performance, but the extra few mm on the wide side are a major advantage for me. All these APS-C lenses are compromises ... Sigma 18-35 is optically excellent, but it has small range, lacks IS and is relatively big/heavy and expensive (although cheap for its spec ...).
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