Retaining the excellent performance at maximum aperture of the much larger f/2.8L but in a smaller size, the EF 70-200mm f/4L USM Lens from Canon 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).
Like every autofocus Canon "L" lens, the EF 70-200mm f/4LUSM 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 autofocus 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 (86% lighter than the EF 70-200mm f/2.8L), 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.