It is my understanding that IS doesn't help much when the subject is moving, is this correct? I need a work lens that will be used almost exclusively for moving subjects, If my comment above is true, the Canon EF 28-135mm f/3.5-5.6 IS doesn't look as attracive as it did.
Has anyone had any experience with the Canon - EF 28-200mm f/3.5-5.6 USM or the Sigma 24-135mm f/2.8-4.5 Aspherical IF? I figure that having the extra 135-200 (Canon) or the extra 24-28 & 2.8 (Sigma) would be more valuable than the IS. My main concern is how these other 2 lenses stack up quality wise to the Canon 28-135.
Thanks for any help.
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