This is pretty interesting zoom lens. Though it is not part of Sigma’s newer, high level line-up, the Sigma 50-150mm f/2.8 EX DC APO OS HSM for full-frame APS-C DSLRs (75-225mm on APS-C) has a constant f/2.8 aperture over the zoom range and optical stabilization, and comes at a price that will not put a hole in your pocket (less than $1000). The Sigma 50-150mm f/2.8 EX DC APO OS is comparable to Canon’s similar specced EF 70-200mm f/2.8L IS USM II. The Canon, though, has a higher price tag (around $2499). ephotozine reviewed the Sigma 50-150mm f/2.8 and gave the lens a rating of 4/5.