Canon's EF 16-35mm f/4 L IS USM lens is a welcome addition to their professional L-series of flagship lenses. It's the perfect lens for serious landscape and architectural photographers who are looking for the highest quality lenses they can get their hands on. This lens is designed for use with Canon's full-frame DSLR cameras line up, combining a superior performance with a solid, dust and moisture resistance design. The lens features an ultrasonic motor (USM) and 4-stop image stabilisation which together provides a quick, accurate and smooth autofocus as well as steady images in any shooting situation. Furthermore, adding to the versatility of this lens, its fixed f4 aperture delivers incredible optical performance and a beautiful soft background blur across the entire focal range