FitMyLensthe lens-by-mount reference

Canon RF 800mm f/11 IS STM vs Canon RF 400mm f/2.8 L IS USM

Both are Canon RF mount primes for telephoto and wildlife — here's how the specs differ and which to pick. Every spec is from the manufacturer's own catalog.

Last verified 2026-06-21 · Canon RF mount · prices change — check the retailer

SpecCanon RF 800mm f/11 IS STMCanon RF 400mm f/2.8 L IS USM
Focal length800mm400mm
Max aperturef/11f/2.8
Typeprimeprime
Coveragefull-framefull-frame
MountCanon RFCanon RF

Which should you buy?

Where to buy

Check the Canon RF 800mm f/11 IS STM price on Amazon →

Check the Canon RF 400mm f/2.8 L IS USM price on Amazon →

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FAQ

What's the difference between the Canon RF 800mm f/11 IS STM and the Canon RF 400mm f/2.8 L IS USM?
The Canon RF 800mm f/11 IS STM is 800mm f/11 prime, full-frame; the Canon RF 400mm f/2.8 L IS USM is 400mm f/2.8 prime, full-frame. Both fit the Canon RF mount.

Which is better in low light, the Canon RF 800mm f/11 IS STM or the Canon RF 400mm f/2.8 L IS USM?
The Canon RF 400mm f/2.8 L IS USM — its f/2.8 maximum aperture lets in more light and gives more background blur than the f/11 of the other.

Do the Canon RF 800mm f/11 IS STM and Canon RF 400mm f/2.8 L IS USM fit the same camera?
Yes — both are Canon RF mount lenses, so they fit Canon EOS R series (full-frame R5/R6/R8) and APS-C (R7/R10/R50).

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