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Canon EF 100mm f/2 USM — Bokeh & Optical Ray-Tracing Simulator
Interactive 3D portrait ray-traced through the published JP S53-133028A optical prescription (6 elements in 4 groups) with a 50.0 mm entrance pupil and 0.9 m minimum focus.
Optical & Portrait Specifications (Upper Body Framing)
| Optical & Portrait Metric | Measured / Patent Value | What It Means in Practice |
|---|---|---|
| Patent Prescription | JP S53-133028A · 6 elements in 4 groups | Traced surface by surface in WebGL2 |
| Entrance Pupil Diameter | 50.0 mm (at f/2) | Controls distant background blur disc size |
| Corner Bokeh Roundness (90% Field) | 79% at f/2 (≥86% from f/2.8) · -0.4 EV | Mechanical vignetting (cat’s-eye vs. round corner highlights) |
| Background Field of View (Compression) | 20° horizontal | Width of the background room visible behind the subject |
| Upper-Body Working Distance | 4.01 m | Camera-to-subject distance for head-to-waist framing |
| Effective Focal Length (Breathing) | 104.3 mm (+4.3%) | Actual framing focal length at portrait distance |
| Depth of Field (Sharp Zone) | 28 cm (3.87 m – 4.15 m) | Sharp zone at wide-open aperture |
| Minimum Focus Distance | 0.9 m | Closest focusing distance from the sensor |
Questions
How much background blur and corner cat's-eye does the Canon EF 100mm f/2 USM produce?
Wide open at f/2, the Canon EF 100mm f/2 USM has a 50.0 mm entrance pupil (100 mm ÷ 2) and 79% bokeh roundness in the 90% corner (-0.4 EV corner falloff, reaching ≥86% roundness from f/2.8). In an upper-body portrait at 4.01 m, the sharp depth-of-field zone spans 28 cm (3.87 m to 4.15 m) with a 20° horizontal background angle of view.
Does the Canon EF 100mm f/2 USM show focus breathing at portrait distance?
Based on patent JP S53-133028A, tracing the focusing group at 4.01 m gives an effective framing focal length of 104.3 mm (+4.3% vs. the nominal 100 mm). You can toggle "Match subject size" in the simulator to see the framing shift live.
What optical design is inside the Canon EF 100mm f/2 USM?
The patent prescription (JP S53-133028A) specifies 6 lens elements in 4 groups. The interactive Optical X-Ray above traces rays through every surface in real time.
Related comparisons
- Canon EF 100mm f/2.8L Macro IS USM
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Compare with similar portrait lenses
- Nikon 105mm f/1.8 AI-s
- Sony FE 100mm F2.8 Macro GM OSS
- Sony FE 100mm F2.8 STF GM OSS
- Canon RF 100mm F2.8 L MACRO IS USM
- Canon EF 135mm f/2.8 Soft Focus
Also see: depth of field, bokeh, crop factor, lens compression.