Canon
RF 10-20mm F4 L IS USM
Canon RF Mount
RF 10-20mm F4 L IS USM — 10–20mm f/4 for Canon RF, a popular choice in the canon lineup.
$2,299
Launch priceReleased Oct 2023
Canon
RF 50mm F1.2L USM
Canon RF Mount
Flagship RF 50mm f/1.2 L prime with Ring USM, 15-element design, and weather-sealed L-series build.
$2,299
Launch priceReleased Dec 2018
RF 10-20mm F4 L IS USM is 4.8 years newer.
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Wins
RF 10-20mm F4 L IS USM
Wins
RF 50mm F1.2L USM
Which would you choose?
TL;DR — Key differences
- ARF 10-20mm F4 L IS USM has higher OIS effectiveness (5.5 stops vs 0 stops)
- BRF 50mm F1.2L USM has lower Max aperture (Wide) (f/1.2 vs f/4)
- BRF 50mm F1.2L USM has lower Max aperture (Tele) (f/1.2 vs f/4)
- ARF 10-20mm F4 L IS USM has lower Min focus distance (24 cm vs 40 cm)
- ARF 10-20mm F4 L IS USM has lower Weight (620 g vs 950 g)
Key specs at a glance
Size and weight, to scale
📸 Snap this lens size diff to share
RF 10-20mm F4 L IS USM
⌀84 × 113 mm
620 g (1.37 lb / 21.87 oz)
Credit card
85.6 × 54 mm
for scale
RF 50mm F1.2L USM
⌀90 × 108 mm
950 g (2.09 lb / 33.51 oz)
RF 10-20mm F4 L IS USM is 5mm longer and 6mm narrower than RF 50mm F1.2L USM.
RF 10-20mm F4 L IS USM is 330 g lighter than RF 50mm F1.2L USM.
Diameter (⌀) is the maximum barrel width; length is measured from the mount to the front of the lens.
Use-case scoring
Which one for what?
Algorithmic scores from verified specs · 10 = best in class
Why pick one over the other
Reasons to choose the RF 10-20mm F4 L IS USM
- ✓
OIS effectiveness
5.5 stops vs 0 stops — higher is better
- ✓
Special elements
Adds 2 UD, 1 Super UD
- ✓
Optical stabilization
Only RF 10-20mm F4 L IS USM supports it
- ✓
Custom function button
Only RF 10-20mm F4 L IS USM supports it
- ✓
Min focus distance
24 cm vs 40 cm — lower is better
- ✓
Weight
620 g vs 950 g — lower is better
- ✓
Diameter
83.6 mm vs 89.8 mm — lower is better
Reasons to choose the RF 50mm F1.2L USM
- ✓
Max aperture (Wide)
f/1.2 vs f/4 — lower is better
- ✓
Max aperture (Tele)
f/1.2 vs f/4 — lower is better
- ✓
Special elements
Adds 1 UD
- ✓
Length
108 mm vs 112.8 mm — lower is better
- ✓
Max magnification
0.19 × vs 0.17 × — higher is better
Shared specifications
Internal focus
Both support internal focus
Weather sealing
Both support weather sealing
Control ring
Both support control ring
Pros & cons at a glance
Editorially curated highlights and trade-offs.
RF 10-20mm F4 L IS USM
Pros
- ✓Versatile zoom range covers multiple focal lengths in one lens
- ✓Built-in optical image stabilization
- ✓Weather-sealed construction for outdoor shooting
Cons
- –Premium price point
- –Slower maximum aperture limits low-light performance
RF 50mm F1.2L USM
Pros
- ✓Stunning sharpness even wide open at f/1.2
- ✓Beautiful, smooth bokeh with 10 rounded aperture blades
- ✓Fast and accurate Dual Pixel AF with Ring USM
- ✓Weather-sealed L-series construction
Cons
- –Heavy for a 50mm prime (950g)
- –Premium price for a single focal length
- –No optical image stabilization
Decided which one is right for you?
Compare live prices for the RF 10-20mm F4 L IS USM and RF 50mm F1.2L USM at major authorized retailers.
Canon RF 10-20mm F4 L IS USM
Canon RF 50mm F1.2L USM
Affiliate disclosure: As an Amazon Associate, Cameraegg earns from qualifying purchases. Cameraegg may also earn commission from B&H links, at no extra cost to you.
Full specifications
✓ = category winner
Specs sourced from manufacturer data. Use-case scores algorithmically derived. Last reviewed June 2026.