Canon RF 20mm F1.4 L VCM — Bokeh & Optical Ray-Tracing Simulator

Interactive 3D portrait ray-traced through the published US20250389929A1 optical prescription (16 elements in 11 groups, 3 aspherical) with a 14.3 mm entrance pupil and 0.2 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	US20250389929A1 · 16 elements in 11 groups (3 aspherical)	Traced surface by surface in WebGL2
Entrance Pupil Diameter	14.3 mm (at f/1.4)	Controls distant background blur disc size
Upper-Body Working Distance	0.84 m	Camera-to-subject distance for head-to-waist framing
Effective Focal Length (Breathing)	18.6 mm (-6.9%)	Actual framing focal length at portrait distance
Depth of Field (Sharp Zone)	22 cm (74 cm – 96 cm)	Sharp zone at wide-open aperture
Minimum Focus Distance	0.2 m	Closest focusing distance from the sensor

Questions

How much background blur does the Canon RF 20mm F1.4 L VCM produce?

Wide open at f/1.4, the Canon RF 20mm F1.4 L VCM has a 14.3 mm entrance pupil (20 mm ÷ 1.4). In an upper-body portrait at 0.84 m, the sharp depth-of-field zone spans 22 cm (74 cm to 96 cm), while mechanical vignetting and 16 glass elements shape the out-of-focus highlights.

Does the Canon RF 20mm F1.4 L VCM show focus breathing at portrait distance?

Based on patent US20250389929A1, tracing the focusing group at 0.84 m gives an effective framing focal length of 18.6 mm (-6.9% vs. the nominal 20 mm). You can toggle "Match subject size" in the simulator to see the framing shift live.

What optical design is inside the Canon RF 20mm F1.4 L VCM?

The patent prescription (US20250389929A1) specifies 16 lens elements in 11 groups with 3 aspherical surfaces. The interactive Optical X-Ray above traces rays through every surface in real time.

Head-to-head patent comparisons with Canon RF 20mm F1.4 L VCM

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