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Canon EF-M 22mm f/2 STM — Bokeh & Optical Ray-Tracing Simulator
Interactive 3D portrait ray-traced through the published US8854747B2 optical prescription (7 elements in 6 groups, 2 aspherical) with a 11.0 mm entrance pupil and 0.15 m minimum focus.
Optical & Portrait Specifications (Upper Body Framing)
| Optical & Portrait Metric | Measured / Patent Value | What It Means in Practice |
|---|---|---|
| Patent Prescription | US8854747B2 · 7 elements in 6 groups (2 aspherical) | Traced surface by surface in WebGL2 |
| Entrance Pupil Diameter | 11.0 mm (at f/2) | Controls distant background blur disc size |
| Corner Bokeh Roundness (90% Field) | 86% at f/2 · -0.5 EV | Mechanical vignetting (cat’s-eye vs. round corner highlights) |
| Background Field of View (Compression) | 56° horizontal | Width of the background room visible behind the subject |
| Upper-Body Working Distance | 1.36 m | Camera-to-subject distance for head-to-waist framing |
| Effective Focal Length (Breathing) | 22.0 mm (+0.1%) | Actual framing focal length at portrait distance |
| Depth of Field (Sharp Zone) | 46 cm (1.17 m – 1.63 m) | Sharp zone at wide-open aperture |
| Minimum Focus Distance | 0.15 m | Closest focusing distance from the sensor |
Questions
How much background blur and corner cat's-eye does the Canon EF-M 22mm f/2 STM produce?
Wide open at f/2, the Canon EF-M 22mm f/2 STM has a 11.0 mm entrance pupil (22 mm ÷ 2) and 86% bokeh roundness in the 90% corner (-0.5 EV corner falloff). In an upper-body portrait at 1.36 m, the sharp depth-of-field zone spans 46 cm (1.17 m to 1.63 m) with a 56° horizontal background angle of view.
Does the Canon EF-M 22mm f/2 STM show focus breathing at portrait distance?
Based on patent US8854747B2, tracing the focusing group at 1.36 m gives an effective framing focal length of 22.0 mm (+0.1% vs. the nominal 22 mm). You can toggle "Match subject size" in the simulator to see the framing shift live.
What optical design is inside the Canon EF-M 22mm f/2 STM?
The patent prescription (US8854747B2) specifies 7 lens elements in 6 groups with 2 aspherical surfaces. The interactive Optical X-Ray above traces rays through every surface in real time.
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Compare with similar portrait lenses
- Fujifilm XF 23mm F2 R WR
- Sony Sonnar E 24mm F1.8 ZA
- Nikon 24mm f/2.0 AI-s
- Sony E 20mm F2.8
- Fujifilm XF 23mm F2.8 R WR
- Fujifilm XF 30mm F2.8 R LM WR Macro
Also see: depth of field, bokeh, crop factor, lens compression.