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. 
 
Super-telephoto prime is designed for use with full-frame Canon RF-mount mirrorless digital cameras. 
 
Fixed f/11 aperture contributes to the sleek and portable form factor as well as a balanced mixture of depth of field and sharpness. 
 
Gapless dual-layer diffractive optics contribute to a marked reduction in chromatic and spherical aberrations as well as benefit the design of a relatively compact and lightweight lens. 
 
Retractable/extendable design, with a locking lens barrel, offers an impressively compact form factor considering the super-telephoto design. 
 
An Optical Image Stabilizer helps to minimize the appearance of camera shake by up to four stops to better enable working in low-light conditions and with slower shutter speeds. 
 
STM stepping motor offers fast, quiet, smooth, and accurate autofocus performance that is ideal for video recording as well as still shooting. 
 
Configurable Control Ring can be used to adjust a variety of exposure settings, including aperture, ISO, and exposure compensation. 
 
Compatible with optional Extender RF 1.4x and Extender RF 2x teleconverters to further increase the effective focal length.Canon RF 800mm f/11 IS STM Lens
Specifications
Brand: Canon
Manufacturer Part Number: 3987C002
Manufacturer: Canon