Canon RF 14mm F1.4 L VCM vs. Canon RF 20mm F1.4 L VCM

Ray-traced side by side from their optical patents for the same upper-body portrait framing: compare the Canon RF 14mm F1.4 L VCM (0.6 m working distance, 10.0 mm pupil) against the Canon RF 20mm F1.4 L VCM (0.8 m working distance, 14.3 mm pupil).

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Portrait At-a-Glance Comparison (Upper Body Framing)

Optical & Portrait Metric	Canon RF 14mm F1.4 L VCM	Canon RF 20mm F1.4 L VCM	What It Means in Practice
Upper-Body Working Distance	0.61 m	0.84 m	The Canon RF 20mm F1.4 L VCM requires 0.2 m more room behind you for the same subject size.
Effective Focal Length (Breathing)	13.0 mm (-6.8%)	18.6 mm (-6.9%)	Canon RF 14mm F1.4 L VCM frames like 13.0 mm (-6.8%) at 0.6 m; Canon RF 20mm F1.4 L VCM frames like 18.6 mm (-6.9%) at 0.8 m.
Depth of Field (Sharp Zone)	24 cm (51 cm – 75 cm)	22 cm (74 cm – 96 cm)	The Canon RF 20mm F1.4 L VCM has a 9% thinner focus zone (24 cm vs. 22 cm)—requiring more precise eye focus.
Entrance Pupil Diameter	10.0 mm (f/1.4)	14.3 mm (f/1.4)	Distant background blur discs are 43% larger on the Canon RF 20mm F1.4 L VCM.
Minimum Focus Distance	0.24 m	0.2 m	Canon RF 20mm F1.4 L VCM focuses 4 cm closer (0.24 m vs. 0.2 m) for tighter close-ups.
Patent Prescription	US20250389929A1 (18/13)	US20250389929A1 (16/11)	Published optical prescriptions traced in the 3D simulator above.

Questions

Which blurs the background more, Canon RF 14mm F1.4 L VCM or Canon RF 20mm F1.4 L VCM?

At the same subject framing, distant background blur scales with the entrance pupil diameter (focal length ÷ f-number). Canon RF 14mm F1.4 L VCM at f/1.4 has a 10.0 mm entrance pupil, while Canon RF 20mm F1.4 L VCM at f/1.4 has a 14.3 mm entrance pupil.

How does working distance differ between Canon RF 14mm F1.4 L VCM and Canon RF 20mm F1.4 L VCM?

For an upper-body portrait, Canon RF 14mm F1.4 L VCM stands 0.61 m from the subject (sharp zone 24 cm, from 51 cm to 75 cm), whereas Canon RF 20mm F1.4 L VCM stands 0.84 m away (sharp zone 22 cm, from 74 cm to 96 cm).

How do the optical designs of Canon RF 14mm F1.4 L VCM and Canon RF 20mm F1.4 L VCM compare?

Canon RF 14mm F1.4 L VCM uses 18 elements in 13 groups (US20250389929A1, effective focal length 13.0 mm at portrait distance). Canon RF 20mm F1.4 L VCM uses 16 elements in 11 groups (US20250389929A1, effective focal length 18.6 mm).

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Canon RF 20mm F1.4 L VCM vs. Canon RF 24mm F1.4 L VCM

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