Canon's lightweight super-telephoto zoom for RF-mount, using diffractive optics for compact design.
The Canon RF 100-400mm f/5.6-8 IS USM launched in 2021 as part of Canon's affordable RF lens range. Using a compact design enabled by the slower f/5.6-8 aperture, it provides super-telephoto reach at a fraction of the weight and price of professional 100-400mm zooms. It targets wildlife enthusiasts and birders on a budget.
Optical quality is good considering the compact design with sharp results at shorter focal lengths. The slow f/8 maximum aperture at 400mm requires good light and limits AF performance on bodies with fewer AF points. IS provides approximately 5.5 stops. Nano USM autofocus is fast and silent. The lens is remarkably light at 635g.
Canon RF mount only, 67mm filter thread. Compatible with Canon's RF 1.4x and 2x teleconverters to extend reach to 560mm and 800mm though the effective aperture becomes very slow. The EF 100-400mm f/4.5-5.6L IS II USM via adapter offers a faster aperture at much greater weight and cost.
Good value used. Check IS operation, AF speed at 400mm, and zoom ring smoothness. The slow aperture is the main limitation so test in various lighting conditions. Excellent for daytime wildlife photography where the compact size and light weight are more important than a fast aperture.