Super long reach, super compact design, the Canon RF 800mm f/11 IS STM
is a unique telephoto prime featuring a distinct mixture of focal
length and form factor. Characterized by its retractable design and a
fixed f/11 aperture, this lens's sleek profile makes handheld super-tele
shooting a very real possibility, and four stop-effective optical image
stabilization further helps to achieve sharp imagery when working in
difficult lighting conditions. Also contributing to the reduced size is a
distinct optical layout, which uses gapless dual-layer diffractive
optics instead of multiple heavier individual elements, which also
effectively controls color fringing and chromatic aberrations for high
clarity. Complementing this design is an STM stepping motor that
delivers quick and quiet autofocus performance that is suitable for both
stills and video needs. Additionally, a Control Ring is also integrated
into the lens design for intuitive control over exposure settings from
the lens itself. If you decide you need more than 800mm, this lens is
compatible with the 1.4x and 2x RF Extenders for an equivalent focal
length of 1120mm or 1600mm, respectively.