Canon EF 35mm f/2 — Bokeh & Optical Ray-Tracing Simulator

Interactive 3D portrait ray-traced through the published JP H04-015611A optical prescription (7 elements in 5 groups) with a 17.5 mm entrance pupil and 0.25 m minimum focus.

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Optical & Portrait Specifications (Upper Body Framing)

Optical & Portrait Metric Measured / Patent Value What It Means in Practice
Patent Prescription JP H04-015611A · 7 elements in 5 groups Traced surface by surface in WebGL2
Entrance Pupil Diameter 17.5 mm (at f/2) Controls distant background blur disc size
Corner Bokeh Roundness (90% Field) 77% at f/2 (≥86% from f/2.8) · -0.7 EV Mechanical vignetting (cat’s-eye vs. round corner highlights)
Background Field of View (Compression) 54° horizontal Width of the background room visible behind the subject
Upper-Body Working Distance 1.42 m Camera-to-subject distance for head-to-waist framing
Effective Focal Length (Breathing) 35.0 mm (+0.0%) Actual framing focal length at portrait distance
Depth of Field (Sharp Zone) 29 cm (1.29 m – 1.58 m) Sharp zone at wide-open aperture
Minimum Focus Distance 0.25 m Closest focusing distance from the sensor

Questions

How much background blur and corner cat's-eye does the Canon EF 35mm f/2 produce?

Wide open at f/2, the Canon EF 35mm f/2 has a 17.5 mm entrance pupil (35 mm ÷ 2) and 77% bokeh roundness in the 90% corner (-0.7 EV corner falloff, reaching ≥86% roundness from f/2.8). In an upper-body portrait at 1.42 m, the sharp depth-of-field zone spans 29 cm (1.29 m to 1.58 m) with a 54° horizontal background angle of view.

Does the Canon EF 35mm f/2 show focus breathing at portrait distance?

Based on patent JP H04-015611A, tracing the focusing group at 1.42 m gives an effective framing focal length of 35.0 mm (+0.0% vs. the nominal 35 mm). You can toggle "Match subject size" in the simulator to see the framing shift live.

What optical design is inside the Canon EF 35mm f/2?

The patent prescription (JP H04-015611A) specifies 7 lens elements in 5 groups. The interactive Optical X-Ray above traces rays through every surface in real time.

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Also see: depth of field, bokeh, crop factor, lens compression.