Canon EF 50mm f/1.4 USM — Bokeh & Optical Ray-Tracing Simulator

Interactive 3D portrait ray-traced through the published JP H06-242370A optical prescription (7 elements in 6 groups) with a 35.7 mm entrance pupil and 0.45 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 H06-242370A · 7 elements in 6 groups Traced surface by surface in WebGL2
Entrance Pupil Diameter 35.7 mm (at f/1.4) Controls distant background blur disc size
Corner Bokeh Roundness (90% Field) 68% at f/1.4 (≥86% from f/2) · -0.8 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) 50.2 mm (+0.5%) Actual framing focal length at portrait distance
Depth of Field (Sharp Zone) 20 cm (1.92 m – 2.12 m) Sharp zone at wide-open aperture
Minimum Focus Distance 0.45 m Closest focusing distance from the sensor

Questions

How much background blur and corner cat's-eye does the Canon EF 50mm f/1.4 USM produce?

Wide open at f/1.4, the Canon EF 50mm f/1.4 USM has a 35.7 mm entrance pupil (50 mm ÷ 1.4) and 68% bokeh roundness in the 90% corner (-0.8 EV corner falloff, reaching ≥86% roundness from f/2). In an upper-body portrait at 2.01 m, the sharp depth-of-field zone spans 20 cm (1.92 m to 2.12 m) with a 39° horizontal background angle of view.

Does the Canon EF 50mm f/1.4 USM show focus breathing at portrait distance?

Based on patent JP H06-242370A, tracing the focusing group at 2.01 m gives an effective framing focal length of 50.2 mm (+0.5% 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 EF 50mm f/1.4 USM?

The patent prescription (JP H06-242370A) specifies 7 lens elements in 6 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.