The Canon 70-200mm f/4L IS is an excellent performer at maximum aperture but smaller in size compared to the Canon 70-200 f/2.8L IS II. The Canon 70-200 f/4L IS is a professional zoom telephoto suitable for a broad range of applications from sports to portraiture.

It is fully compatible with the Extender EF 1.4x II and 2x II teleconverters (requires f/8 AF sensitivity with EF 2x II) and features optical image stabilization (IS) to reduce the blur caused by camera shake. The image stabilization provides the equivalent effect of a shutter speed 4 stops faster and offers an IS mode optimized for following shots of moving subjects. 

Like every auto focus Canon "L" lens, the EF 70-200mm f/4L USM delivers optical performance equal to similar fixed focal length lenses, with silent, high-speed ultrasonic (USM) focusing and full-time manual focus override capacity. A focus range limiting option also enables faster auto focus rates. 

Distortions and aberrations are remarkably small for a lens of such capability. This lens combines 1 artificial fluorite element with 2 UD (Ultra-low Dispersion) elements to help achieve images free of secondary spectrum aberrations, which are often the bane of consumer-grade telephoto zooms. It is light enough to not need a tripod collar, but for handling purposes there is an optional tripod collar.

The minimum focusing distance is 3.9' (1.2m) throughout its entire range of focal lengths, and it accepts 67mm screw-in filters. A tight seal structure provides protection from dust and moisture for optimal performance in difficult environments.