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
Sony
FE 40mm F2.5 G
Sony E Mount
FE 40mm F2.5 G — 40mm f/2.5 for Sony E, a popular choice in the sony lineup.
$599
Launch priceReleased Apr 2021
FE 40mm F2.5 G is 2.3 years newer.
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Wins
RF 50mm F1.2L USM
Wins
FE 40mm F2.5 G
1 categories tied
Which would you choose?
TL;DR — Key differences
- BFE 40mm F2.5 G has lower Weight (173 g vs 950 g)
- ARF 50mm F1.2L USM has lower Max aperture (Wide) (f/1.2 vs f/2.5)
- ARF 50mm F1.2L USM has lower Max aperture (Tele) (f/1.2 vs f/2.5)
- BFE 40mm F2.5 G has lower Length (74 mm vs 108 mm)
- BFE 40mm F2.5 G has lower Min focus distance (30 cm vs 40 cm)
Key specs at a glance
Size and weight, to scale
📸 Snap this lens size diff to share
RF 50mm F1.2L USM
⌀90 × 108 mm
950 g (2.09 lb / 33.51 oz)
Credit card
85.6 × 54 mm
for scale
FE 40mm F2.5 G
⌀81 × 74 mm
173 g (0.38 lb / 6.10 oz)
RF 50mm F1.2L USM is 34mm longer and 9mm wider than FE 40mm F2.5 G.
RF 50mm F1.2L USM is 777 g heavier than FE 40mm F2.5 G.
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 50mm F1.2L USM
- ✓
Special elements
Adds 1 UD, 1 Aspherical
- ✓
Max aperture (Wide)
f/1.2 vs f/2.5 — lower is better
- ✓
Max aperture (Tele)
f/1.2 vs f/2.5 — lower is better
- ✓
Weather sealing
Only RF 50mm F1.2L USM supports it
- ✓
Control ring
Only RF 50mm F1.2L USM supports it
- ✓
Max magnification
0.19 × vs 0.15 × — higher is better
Reasons to choose the FE 40mm F2.5 G
- ✓
Special elements
Adds Aspherical
- ✓
Weight
173 g vs 950 g — lower is better
- ✓
Length
74 mm vs 108 mm — lower is better
- ✓
Min focus distance
30 cm vs 40 cm — lower is better
- ✓
Diameter
81 mm vs 89.8 mm — lower is better
Shared specifications
Internal focus
Both support internal focus
Pros & cons at a glance
Editorially curated highlights and trade-offs.
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
FE 40mm F2.5 G
Pros
- ✓Prime design typically delivers strong sharpness and lighter weight
- ✓Lightweight design easy to carry all day
- ✓Native Sony E mount compatibility
Cons
- –Third-party or older alternatives may offer better value
Decided which one is right for you?
Compare live prices for the RF 50mm F1.2L USM and FE 40mm F2.5 G at major authorized retailers.
Canon RF 50mm F1.2L USM
Sony FE 40mm F2.5 G
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Full specifications
✓ = category winner
Specs sourced from manufacturer data. Use-case scores algorithmically derived. Last reviewed October 2026.