EF 600mm f/4L IS III USM is a Canon

L-series super telephoto lens distinguished by its advanced, lightweight design, quick and intuitive handling, and high speed performance.

Using fluorite, Super UD, and aspherical elements, both chromatic and spherical aberrations are kept to minimum in order to realize sharp,

clear image quality with accurate rendering and color fidelity. Both Super Spectra and Air Sphere Coatings also contribute to color accuracy and helps to control flare and ghosting when working in backlit and harsh lighting conditions.

In addition to its optical merits, the 600mm f/4 is also characterized by its advanced five stop-effective Image Stabilizer system,

which has three separate stabilization modes to suit various shooting applications. Also complementing handling is a sophisticated ring-type USM, which provides quick, quiet, and accurate autofocus performance along with full-time manual focus override.

A customizable electronic focusing ring further contributes to precise manual focus control, by affording three focusing sensitivity levels for different applications.

Additionally, this lens is weather-sealed for use in trying environmental conditions and it has a removable rotating tripod collar to benefit working atop a tripod or monopod.