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
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 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). 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), while mechanical vignetting and 7 glass elements shape the out-of-focus highlights.

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.

Head-to-head patent comparisons with Canon EF 50mm f/1.4 USM

Canon EF 50mm f/1.4 USM vs. Canon EF 50mm f/1.8 II

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