Canon RF100-400mm F5.6-8 IS USM review: a 635 g route to 400mm on Canon RF

Why it exists. Canon pitched the RF100-400mm at people who had never owned a long lens. Its September 14, 2021 release says: "It's an affordable and easily hand-holdable entry into the world of super-telephoto, full-frame photography and video."

The numbers back that up. Canon lists 635 g and 164.7 mm long, with a 67mm filter thread, against more than 2 kg for the 600mm zooms. Inside are 12 elements in 9 groups with one UD and one aspherical element, a 9-blade aperture, a Nano USM motor and image stabilization rated at 5.5 stops (6 with coordinated IS on supported bodies). It works with Canon's RF1.4x and RF2x extenders for 560mm and 800mm.

The cost of that size is a slow f/8 at 400mm and no weather sealing, and the ET-74B hood is sold separately. It focuses close, though: 0.41x at 400mm. Who should buy it? Canon RF shooters, especially on APS-C bodies such as the R7 and R10, who want reach without the weight. Our gallery: a warbler in Darjeeling, a fritillary butterfly, a honey bee, a running dog and a dunnock.

Canon U.S.A. announced the RF100-400mm F5.6-8 IS USM on September 14, 2021, at $649.99 (Canon U.S.A. release).

Optical design, focus distances, size and weight below come from Canon USA's product page.

Five photos taken with the Canon RF100-400mm F5.6-8 IS USM, shared on Wikimedia Commons under Creative Commons licenses. Select a photo to enlarge it.