Does the Canon RF 800mm f/11 IS STM take a teleconverter?

Canon RF · 800mm f/11 · thread and mount data verified 2026-09-02

2 teleconverters are supported. A teleconverter multiplies the focal length and costs you light — and on a crop body the framing multiplies again.

Read the restriction before you buy: On Canon's Extender RF1.4x compatibility list. The resulting f/16 is computed and sits at the edge of EOS R AF capability; Canon's 'may lose AF functionality' extender disclaimer for this lens was not separately verified for the 1.4x. That is a published limit, not a reviewer's opinion — the usable range with a converter fitted is narrower than the lens's own.

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Teleconverter	Supported	Reach	Max aperture	On APS-C	On Micro Four Thirds
Canon RF Extender 1.4x	Partial — On Canon's Extender RF1.4x compatibility list. The resulting f/16 is computed and sits at the edge of EOS R AF capability; Canon's 'may lose AF functionality' extender disclaimer for this lens was not separately verified for the 1.4x.	1120mm	f/16	1792mm	—
Canon RF Extender 2x	Partial — 'May lose AF functionality' disclaimer. 1600mm is the manufacturer figure; f/22 (computed from the lens aperture, not a manufacturer figure).	1600mm	f/22	2560mm	—

At f/22 many bodies will not autofocus at all — check your body's stated AF aperture limit before buying. At f/16 many bodies will not autofocus at all — check your body's stated AF aperture limit before buying.

What each converter gives you

Canon RF Extender 2x — 1600mm at f/22 on this lens.

Canon RF Extender 1.4x — 1120mm at f/16 on this lens.

The lens itself: Canon RF 800mm f/11 IS STM · every Canon RF lens: Canon RF lens index · all teleconverter compatibility

Compatibility sourced from the manufacturers' own published teleconverter compatibility statements (manufacturer teleconverter compatibility statements (Sony, Canon USA, Nikon, Fujifilm, Sigma, Panasonic, OM System) — each row carries its own source URL) and verified 2026-09-02. Reach and aperture figures are computed from the lens's own published focal length and maximum aperture — a 1.4x multiplies focal length by 1.4 and costs 1 stop; a 2x multiplies by 2 and costs 2 stops. Lenses whose compatibility we could not verify from a manufacturer statement are omitted rather than guessed. Methodology