Most of our readers have been eagerly awaiting the Sigma APO 50-150mm F2.8 EX DC HSM, a unique lens for APS-C sensor digital SLRs. A few weeks ago, this wonderful f/2.8 lens started shipping to the first batch of buyers.
This telephoto zoom appears to be a good buy for photographers with limited budget, though care must be taken as it exhibits the same issues as other Sigma lenses, like focusing inconsistency. A Sigma 50-150 user has posted his review of this lens and states that this lens is sharp at f/4 and smaller, so its f/2.8 designation is quite of questionable value. Chromatic aberration and front-focusing was also noticed, so take note of these issues before acquiring this lens.
Another user has shared samples from the Sigma 50-150, perhaps a lucky guy who managed to get a very good copy. From his samples, this lens should be very good if you get an excellent unit. But is the trouble really worth it? At its price range, the Canon 70-200mm f/4L is just within range and should be a better value. And you get more reach in the long end of the zoom.