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Canon RF 85mm F1.2 L USM DS — Bokeh & Optical Ray-Tracing Simulator
Interactive 3D portrait ray-traced through the published US20200012073A1 optical prescription (14 elements in 9 groups, 1 aspherical) with a 70.8 mm entrance pupil and 0.85 m minimum focus.
Optical & Portrait Specifications (Upper Body Framing)
| Optical & Portrait Metric | Measured / Patent Value | What It Means in Practice |
|---|---|---|
| Patent Prescription | US20200012073A1 · 14 elements in 9 groups (1 aspherical) | Traced surface by surface in WebGL2 |
| Entrance Pupil Diameter | 70.8 mm (at f/1.2) | Controls distant background blur disc size |
| Upper-Body Working Distance | 3.41 m | Camera-to-subject distance for head-to-waist framing |
| Effective Focal Length (Breathing) | 88.4 mm (+4.0%) | Actual framing focal length at portrait distance |
| Depth of Field (Sharp Zone) | 17 cm (3.33 m – 3.49 m) | Sharp zone at wide-open aperture |
| Minimum Focus Distance | 0.85 m | Closest focusing distance from the sensor |
Questions
How much background blur does the Canon RF 85mm F1.2 L USM DS produce?
Wide open at f/1.2, the Canon RF 85mm F1.2 L USM DS has a 70.8 mm entrance pupil (85 mm ÷ 1.2). In an upper-body portrait at 3.41 m, the sharp depth-of-field zone spans 17 cm (3.33 m to 3.49 m), while mechanical vignetting and 14 glass elements shape the out-of-focus highlights.
Does the Canon RF 85mm F1.2 L USM DS show focus breathing at portrait distance?
Based on patent US20200012073A1, tracing the focusing group at 3.41 m gives an effective framing focal length of 88.4 mm (+4.0% vs. the nominal 85 mm). You can toggle "Match subject size" in the simulator to see the framing shift live.
What optical design is inside the Canon RF 85mm F1.2 L USM DS?
The patent prescription (US20200012073A1) specifies 14 lens elements in 9 groups with 1 aspherical surfaces. The interactive Optical X-Ray above traces rays through every surface in real time.
Head-to-head patent comparisons with Canon RF 85mm F1.2 L USM DS
Related comparisons
- Canon RF 85mm F1.2 L USM
- Nikon NIKKOR Z 85mm f/1.2 S
- Sony FE 85mm F1.4 GM II
- Sony FE 85mm F1.4 GM
- Nikon 85mm f/1.4 G FX
- Nikon 105mm f/1.4 FX
Also see: depth of field, bokeh, crop factor, lens compression.