Does the Canon RF 100-300mm f/2.8 L IS USM take a teleconverter?
2 teleconverters are supported. A teleconverter multiplies the focal length and costs you light — and on a crop body the framing multiplies again.
Both converters are supported and both stay usable: 140-420mm at f/4 with the 1.4x, 200-600mm at f/5.6 with the 2x. On a lens this fast the 2x is the unusual case of a 2x that does not cost you autofocus.
| Teleconverter | Supported | Reach | Max aperture | On APS-C | On Micro Four Thirds |
|---|---|---|---|---|---|
| Canon RF Extender 1.4x | Yes — On Canon's Extender RF1.4x compatibility list. The resulting f/4 is computed (1-stop loss), not a Canon figure. | 140-420mm | f/4 | 224-672mm | — |
| Canon RF Extender 2x | Yes — No restriction stated. Single-source (not on the extender page's stale list). | 200-600mm | f/5.6 | 320-960mm | — |
What each converter gives you
Canon RF Extender 2x — 200-600mm at f/5.6 on this lens, autofocus retained.
Canon RF Extender 1.4x — 140-420mm at f/4 on this lens.
The lens itself: Canon RF 100-300mm f/2.8 L IS USM · 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