Focus diameter

Features:- - EF Mount L-Series Lens - Aperture Range: f/4-22 - Three Aspherical Elements, One Super UD - Ultrasonic Autofocus Motor - Manual Focus Override - Water and Dust Resistant - Internal Zooming and Focusing - Truly Circular Diaphragm - 77mm Front Filter Diameter - Rear Holder for Three Gel Filters In the Box - Canon EF 17-40mm f/4L USM Lens - E-77 II 77mm Lens Cap - Lens Dust Cap E (Rear) - EW-83E Lens Hood - Lens Case LP1319 - Limited 1-Year Warranty

Waterproof (up to 1 m for 10 minutes) and fog-proof with O-ring seals and nitrogen gas for added resistance to the elements. Close-focusing distance of only 5 m. Turn-and-slide rubber eyecups with multi-click system make it easy to position your eye at the correct eyepoint. Eco-glass optics, free of lead and arsenic, are used for all lenses and prisms. Magnification: 8X Effective Objective Diameter: 42mm Field of View at 1,000m: 122m Exit Pupil: 5.3mm Brightness: 28.1 Eye Relief: 19.7mm Close Focus Distance: 5.0m Interpupillary Distance Adjustment: 56-72mm Length: 154mm Width: 131mm Depth: 58mm Weight: 670g Waterproof: Yes