Canon EF 400mm lens

These lenses have an EF mount that work with the EOS line of cameras.

[1] Canon has manufactured four 400mm prime lenses: The 400mm f/4 DO IS II USM, which replaced an earlier version of the same lens in 2014,[3] is one of only two Canon lenses that make use of diffractive optics (the other is the EF 70–300mm f/4.5–5.6 DO IS USM).

[4][5] These lenses are compatible with the Canon Extender EF teleconverters.

Canon 400 mm f/2.8 L IS II USM lenses are used in the Dragonfly Telephoto Array.

[15] The array is designed to image astronomical objects with low surface brightness such as some satellite galaxies.

The moon as seen through the EF 400mm f/5.6L USM with a teleconverter