Canon RF-S 10-18mm f/4.5-6.3 IS STM vs Canon RF 10-20mm f/4 L IS STM

Both are Canon RF mount zooms for wide-angle — here's how the specs differ and which to pick. Every spec is from the manufacturer's own catalog.

Last verified 2026-09-01 · Canon RF mount · prices change — check the retailer

Spec	Canon RF-S 10-18mm f/4.5-6.3 IS STM	Canon RF 10-20mm f/4 L IS STM
Focal length	10-18mm	10-20mm
Max aperture	f/4.5-6.3	f/4
Type	zoom	zoom
Coverage	APS-C	full-frame
Mount	Canon RF	Canon RF

Which should you buy?

the Canon RF 10-20mm f/4 L IS STM opens wider (f/4) — brighter in low light and more background blur
the Canon RF-S 10-18mm f/4.5-6.3 IS STM covers 10-18mm and the Canon RF 10-20mm f/4 L IS STM covers 10-20mm — pick the range that matches what you shoot
the Canon RF 10-20mm f/4 L IS STM covers full-frame (also works on APS-C bodies); the Canon RF-S 10-18mm f/4.5-6.3 IS STM is APS-C-only — it won't fill a full-frame sensor

Where to buy

CANON Objectif RF-S 10-18mm f/4.5-6.3 is STM Warranty 2 ans

Canon RF-S 10-18mm f/4.5-6.3 IS STMSee price on Amazon Amazon has no new-stock listing for this one right now — this button runs an Amazon search for it rather than opening a product page.

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Canon RF10-20mm F4 L is STM, Ultra-Wide-Angle Lens for Full-Frame Cameras, Compact & Lightweight, Great for Still Photog

Canon RF 10-20mm f/4 L IS STMSee price on Amazon

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FAQ

What's the difference between the Canon RF-S 10-18mm f/4.5-6.3 IS STM and the Canon RF 10-20mm f/4 L IS STM?
The Canon RF-S 10-18mm f/4.5-6.3 IS STM is 10-18mm f/4.5-6.3 zoom, APS-C; the Canon RF 10-20mm f/4 L IS STM is 10-20mm f/4 zoom, full-frame. Both fit the Canon RF mount.

Which is better in low light, the Canon RF-S 10-18mm f/4.5-6.3 IS STM or the Canon RF 10-20mm f/4 L IS STM?
The Canon RF 10-20mm f/4 L IS STM — its f/4 maximum aperture lets in more light and gives more background blur than the f/4.5-6.3 of the other.

Do the Canon RF-S 10-18mm f/4.5-6.3 IS STM and Canon RF 10-20mm f/4 L IS STM 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). Note the Canon RF-S 10-18mm f/4.5-6.3 IS STM is APS-C-only and won't fill a full-frame sensor.

Citing these specs? Go ahead — manufacturer data, last verified 2026-09-01. Copy a ready-made reference:

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Canon RF 10-20mm f/4 L IS STMAffiliate linkSee price on Amazon