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Matching lenses from each maker's lineup, plus some classic medium and large format lenses. Email me if something is wrong or missing.
Canon RF 50mm F1.2 L USM — Bokeh & Optical Ray-Tracing Simulator
Interactive 3D portrait ray-traced through the published US20190265441A1 optical prescription (15 elements in 9 groups, 3 aspherical) with a 41.7 mm entrance pupil and 0.4 m minimum focus.
Optical & Portrait Specifications (Upper Body Framing)
| Optical & Portrait Metric | Measured / Patent Value | What It Means in Practice |
|---|---|---|
| Patent Prescription | US20190265441A1 · 15 elements in 9 groups (3 aspherical) | Traced surface by surface in WebGL2 |
| Entrance Pupil Diameter | 41.7 mm (at f/1.2) | Controls distant background blur disc size |
| Corner Bokeh Roundness (90% Field) | 41% at f/1.2 (≥86% from f/5.6) · -1.5 EV | Mechanical vignetting (cat’s-eye vs. round corner highlights) |
| Background Field of View (Compression) | 39° horizontal | Width of the background room visible behind the subject |
| Upper-Body Working Distance | 2.01 m | Camera-to-subject distance for head-to-waist framing |
| Effective Focal Length (Breathing) | 50.8 mm (+1.6%) | Actual framing focal length at portrait distance |
| Depth of Field (Sharp Zone) | 17 cm (1.93 m – 2.10 m) | Sharp zone at wide-open aperture |
| Minimum Focus Distance | 0.4 m | Closest focusing distance from the sensor |
Questions
How much background blur and corner cat's-eye does the Canon RF 50mm F1.2 L USM produce?
Wide open at f/1.2, the Canon RF 50mm F1.2 L USM has a 41.7 mm entrance pupil (50 mm ÷ 1.2) and 41% bokeh roundness in the 90% corner (-1.5 EV corner falloff, reaching ≥86% roundness from f/5.6). In an upper-body portrait at 2.01 m, the sharp depth-of-field zone spans 17 cm (1.93 m to 2.10 m) with a 39° horizontal background angle of view.
Does the Canon RF 50mm F1.2 L USM show focus breathing at portrait distance?
Based on patent US20190265441A1, tracing the focusing group at 2.01 m gives an effective framing focal length of 50.8 mm (+1.6% vs. the nominal 50 mm). You can toggle "Match subject size" in the simulator to see the framing shift live.
What optical design is inside the Canon RF 50mm F1.2 L USM?
The patent prescription (US20190265441A1) specifies 15 lens elements in 9 groups with 3 aspherical surfaces. The interactive Optical X-Ray above traces rays through every surface in real time.
Related comparisons
- Canon RF 50mm F1.2 L USM vs. Canon RF 50mm F1.8 STM
- Canon RF 50mm F1.2 L USM vs. Canon RF 50mm F1.4 L VCM
- Canon RF 50mm F1.2 L USM vs. Canon RF 45mm F1.2 STM
- Canon RF 50mm F1.2 L USM vs. Fujifilm GF 80mm F1.7 R WR
- Canon RF 50mm F1.2 L USM vs. Canon RF 85mm F1.2 L USM
- Canon RF 50mm F1.2 L USM vs. Canon 50mm f/0.95
Compare with similar portrait lenses
- Sony FE 50mm F1.2 GM
- Nikon NIKKOR Z 50mm f/1.2 S
- Leica NOCTILUX 50mm f/1.2 ASPH
- Sony FE 50mm F1.4 GM
- Sony Planar FE 50mm F1.4 ZA
- Canon RF 85mm F2 MACRO IS STM
Also see: depth of field, bokeh, crop factor, lens compression.