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Canon RF 135mm F1.8 L IS USM — Bokeh & Optical Ray-Tracing Simulator
Interactive 3D portrait ray-traced through the published US20230213745A1 optical prescription (17 elements in 12 groups) with a 75.0 mm entrance pupil and 0.7 m minimum focus.
Optical & Portrait Specifications (Upper Body Framing)
| Optical & Portrait Metric | Measured / Patent Value | What It Means in Practice |
|---|---|---|
| Patent Prescription | US20230213745A1 · 17 elements in 12 groups | Traced surface by surface in WebGL2 |
| Entrance Pupil Diameter | 75.0 mm (at f/1.8) | 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) | 132.7 mm (-1.7%) | Actual framing focal length at portrait distance |
| Depth of Field (Sharp Zone) | 25 cm (5.28 m – 5.53 m) | Sharp zone at wide-open aperture |
| Minimum Focus Distance | 0.7 m | Closest focusing distance from the sensor |
Questions
How much background blur does the Canon RF 135mm F1.8 L IS USM produce?
Wide open at f/1.8, the Canon RF 135mm F1.8 L IS USM has a 75.0 mm entrance pupil (135 mm ÷ 1.8). In an upper-body portrait at 5.40 m, the sharp depth-of-field zone spans 25 cm (5.28 m to 5.53 m), while mechanical vignetting and 17 glass elements shape the out-of-focus highlights.
Does the Canon RF 135mm F1.8 L IS USM show focus breathing at portrait distance?
Based on patent US20230213745A1, tracing the focusing group at 5.40 m gives an effective framing focal length of 132.7 mm (-1.7% 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 RF 135mm F1.8 L IS USM?
The patent prescription (US20230213745A1) specifies 17 lens elements in 12 groups. The interactive Optical X-Ray above traces rays through every surface in real time.
Head-to-head patent comparisons with Canon RF 135mm F1.8 L IS USM
- Canon RF 135mm F1.8 L IS USM vs. Canon RF 85mm F1.2 L USM
- Canon RF 135mm F1.8 L IS USM vs. Canon 135mm f/2 L
- Canon RF 135mm F1.8 L IS USM vs. Nikon NIKKOR Z 135mm f/1.8 S Plena
- Canon RF 135mm F1.8 L IS USM vs. Sony FE 135mm F1.8 GM
Related comparisons
- Sony FE 135mm F1.8 GM
- Nikon NIKKOR Z 135mm f/1.8 S Plena
- Canon 135mm f/2 L
- Nikon AF DC 135mm f/2D
- Nikon 105mm f/1.4 FX
- Canon RF 85mm F1.2 L USM
Also see: depth of field, bokeh, crop factor, lens compression.