Lens comparison · Canon RF / RF-S · updated 5 November 2026

Canon RF-S 10-18mm f/4.5-6.3 IS STM vs Tamron 11-20mm f/2.8 Di III-A RXD

Canon RF-S 10-18mm f/4.5-6.3 IS STM10-18mm · f/4.5-6.3 · 150g
Tamron 11-20mm f/2.8 Di III-A RXD11-20mm · f/2.8 · 335g
Verdict

Canon RF-S 10-18mm f/4.5-6.3 IS STM has more in its favour on paper. The 11-20mm f/2.8 Di III-A RXD gathers more light for low light and background blur; the RF-S 10-18mm f/4.5-6.3 IS STM is lighter and cheaper. The Canon lens is the mount maker's own, while the Tamron is a third-party alternative.

Choose the RF-S 10-18mm f/4.5-6.3 IS STM for

  • less weight (150g vs 335g)
  • a lower price (about £190 vs £400)
  • a wider starting focal length (10mm vs 11mm)
  • optical stabilisation

Choose the 11-20mm f/2.8 Di III-A RXD for

  • a brighter maximum aperture (f/2.8, about 1.4 stops more light)
  • more reach (20mm vs 18mm)
  • weather sealing
  • a constant aperture through the zoom range
RF-S 10-18mm f/4.5-6.3 IS STM11-20mm f/2.8 Di III-A RXD
BrandCanonTamron
Focal length10-18mm11-20mm
Maximum aperturef/4.5-6.3f/2.8
Weight150 g335 g
StabilisationYesNo
Weather sealingNoYes
Filter size49mm67mm
Made forAPSCAPSC
New price£329£599
Used at MPB (Canon RF / RF-S)£98–£284£339–£459

More lens comparisons

RF-S 10-18mm f/4.5-6.3 IS STM vs 10-18mm f/2.8 DC DN ContemporaryE PZ 10-20mm f/4 G vs 11-20mm f/2.8 Di III-A RXD10-18mm f/2.8 DC DN Contemporary vs 11-20mm f/2.8 Di III-A RXD

See all Canon RF / RF-S cameras and lenses.

Frequently asked questions

Is the Canon RF-S 10-18mm f/4.5-6.3 IS STM better than the Tamron 11-20mm f/2.8 Di III-A RXD?

The RF-S 10-18mm f/4.5-6.3 IS STM offers less weight (150g vs 335g), a lower price (about £190 vs £400), a wider starting focal length (10mm vs 11mm); the 11-20mm f/2.8 Di III-A RXD offers a brighter maximum aperture (f/2.8, about 1.4 stops more light), more reach (20mm vs 18mm), weather sealing.

Which is better value, the RF-S 10-18mm f/4.5-6.3 IS STM or the 11-20mm f/2.8 Di III-A RXD?

On Canon RF / RF-S, the Canon RF-S 10-18mm f/4.5-6.3 IS STM costs about £190 against about £400 for the Tamron 11-20mm f/2.8 Di III-A RXD (MPB used where listed, otherwise new; checked 5 November 2026).

Is f/2.8 worth it over f/4.5?

f/2.8 gathers about 1.4 stops more light, which helps indoors, at night and for background blur. If you mostly shoot in good light, the slower lens is usually lighter and cheaper.

Do both lenses fit the same cameras?

Both are available for Canon RF / RF-S (and other mounts: Sony E / FE, Fujifilm X). Both are made for crop sensors.