Introduced in 1999, the Canon EF 300mm f/2.8L IS USM has long been regarded as a benchmark in Canon’s lineup in terms of image sharpness and focusing performance. At the time of its introduction, the EF 300mm f/2.8L IS replaced the very successful EF 300mm f/2.8L USM which was one of Canons best lenses. With this update, Canon gave the EF 300mm f/2.8L IS USM a wholly new optical formula with one fluorite element and two UD-glass elements along with image stabilization. These additions allowed the lens to reach incredible levels of sharpness at even at wide open apertures while the stabilization greatly increased the potential for using the lens effectively while handheld. The lens was finally retired in 2011 with the introduction of the Canon EF 300mm f/2.8L IS USM II but remains a wonderful lens that gives up little to its newer brother in overall performance. I personally obtained a copy of the lens four years ago and it has been my companion on multiple trips across the world over that time. At first, I paired the lens with the Canon 1D III camera body and later a Canon 1Dx with both cameras being used in this review.
For the rest of the review you can go here on the Photographylife website where I write.