When used on a camera with a field of view compensation factor of 1.6x, such as the Canon EOS 400D, they provide a narrower field of view, equivalent to an 800 mm lens mounted on a 35mm frame body. With a 1.3x body such as the Canon EOS-1D Mark III, they provide a less narrow field of view, equivalent to a 650mm lens mounted on a 35mm frame body.
Three EF 500mm lenses have been available, and all are L series lenses. The most recent, the f/4L IS II, released in 2012 and is the only model in production.
The EF 500mm f/4.5L USM is a professional L series lens that is now discontinued. This lens is constructed with a metal body and mount, and with plastic extremities and switches. Features of this lens include a wide rubber focus ring that is damped, a distance window with infrared index, the ability to limit the focus range, a focus-preset mechanism, and the ability to set the AF speed. A 9 bladed maximum aperture of f/4.5, gives this lens the ability to create depth of field effects. The optical construction of this lens contains 8 lens elements, including one fluorite lens element, and one UD (Ultra low Dispersion) lens element. This lens uses an inner focusing system, powered by a ring type USM motor. The front of the lens does not rotate nor extend when focusing. This lens is compatible with the Canon Extender EF teleconverters.
The EF 500mm f/4L IS USM is a professional L series lens that was designed to replace the EF 500mm f/4.5L USM. This lens is constructed with a metal body and mount, and with plastic extremities and switches. Features of this lens are: a wide rubber focus ring that is damped, a distance window with infrared index, the ability to limit the focus range from: 4.5m to infinity, 4.5m to 10m, and 10m to infinity, it also has a focus-preset mechanism, an image stabilizer that is effective up to two stops and is tripod sensing, an AF stop switch, and weather sealing. An 8 bladed maximum aperture of f/4 gives this lens the ability to create depth of field effects. The optical construction of this lens contains 17 lens elements, including one fluorite lens element, and two UD Lens elements. This lens uses an inner focusing system, powered by a ring type USM motor. The front of the lens does not rotate nor extend when focusing. This lens is compatible with the Canon Extender EF teleconverters.
EF 500mm f/4L IS II USM
The EF 500mm f/4L IS II USM is the replacement to the EF 500mm f/4L IS USM. Its specifications are roughly similar to those of the f/4 Mark I, but have a number of significant differences. The Mark II version contains one fewer lens element than its predecessor (16 as opposed to 17), and is 680 grams (1.50 lb) lighter. It also has a 9-blade aperture instead of the 8 blades of the Mark I.[6]
