Features:

• High Magnification Ultra Telephoto Zoom Lens, with a 10x zoom ratio from 50mm to 500mm, optimized for digital SLR cameras.
• Most effective coating for minimizing flare and ghost with digital SLR cameras.
• Triple-cam Rear Focusing System ensures high precision throughout the whole focus range.
• Uses four SLD (the special low dispersion) glass elements for superior optical performance.
• Accepts both 1.4X and 2X APO EX Tele-Converters, the lens can be used as a 1000mm ultra-telephoto zoom lens.

Editor Reviews:

Product Description:
This high zoom ratio lens is optimized for digital SLR cameras and capable of covering a wide range of focal lengths from 50mm standard to 500mm ultra telephoto. In addition, the new super coating on each glass surface produces superb color rendition, while reducing flare and ghosting.This lens uses four pieces of SLD (the special low dispersion) glass for excellent correction of color aberration throughout the entire zoom range.This lens also features a Zoom Lock device to eliminate "Zoom Creep" when the lens is tilted down. When the lens is set to the 50mm focal length, it is remarkably compact and provides easy handling. The tripod mount is composed of magnesium, to minimize total weight and also it is easy to grip and carry the lens due to ergonomic design of the tripod mount.Non-rotating front lens elements, due to rear focus mechanism make possible the use of a custom bayonet "Petal-type Hood", which prevents extraneous light from degrading the image quality. This mechanism also allows the use of circular polarizing filters, since the front barrel does not rotate during focusing or zooming.

Rating : - Dont spend the money
This is an ok lens, but I had to sell it less than 6 months later becuase it just was not up to speed with the zoom and f stops.....Trust me on this, get the canon (IS if you can afford it)a 2x if you need and you are set. this lens is OK, but why get OK when you can get amazing for almost the same price.