Canon 135mm f/2 L — Bokeh & Optical Ray-Tracing Simulator

Interactive 3D portrait ray-traced through the published JP2018-049102A optical prescription (10 elements in 8 groups) with a 67.5 mm entrance pupil and 0.9 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	JP2018-049102A · 10 elements in 8 groups	Traced surface by surface in WebGL2
Entrance Pupil Diameter	67.5 mm (at f/2)	Controls distant background blur disc size
Upper-Body Working Distance	5.40 m	Camera-to-subject distance for head-to-waist framing
Effective Focal Length (Breathing)	138.8 mm (+2.8%)	Actual framing focal length at portrait distance
Depth of Field (Sharp Zone)	28 cm (5.27 m – 5.55 m)	Sharp zone at wide-open aperture
Minimum Focus Distance	0.9 m	Closest focusing distance from the sensor

Questions

How much background blur does the Canon 135mm f/2 L produce?

Wide open at f/2, the Canon 135mm f/2 L has a 67.5 mm entrance pupil (135 mm ÷ 2). In an upper-body portrait at 5.40 m, the sharp depth-of-field zone spans 28 cm (5.27 m to 5.55 m), while mechanical vignetting and 10 glass elements shape the out-of-focus highlights.

Does the Canon 135mm f/2 L show focus breathing at portrait distance?

Based on patent JP2018-049102A, tracing the focusing group at 5.40 m gives an effective framing focal length of 138.8 mm (+2.8% vs. the nominal 135 mm). You can toggle "Match subject size" in the simulator to see the framing shift live.

What optical design is inside the Canon 135mm f/2 L?

The patent prescription (JP2018-049102A) specifies 10 lens elements in 8 groups. The interactive Optical X-Ray above traces rays through every surface in real time.

Head-to-head patent comparisons with Canon 135mm f/2 L

Canon 135mm f/2 L vs. Canon RF 135mm F1.8 L IS USM

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