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Canon RF 35mm F1.8 MACRO IS STM — Bokeh & Optical Ray-Tracing Simulator
Interactive 3D portrait ray-traced through the published US20190113711A1 optical prescription (11 elements in 9 groups, 1 aspherical) with a 19.4 mm entrance pupil and 0.17 m minimum focus.
Optical & Portrait Specifications (Upper Body Framing)
| Optical & Portrait Metric | Measured / Patent Value | What It Means in Practice |
|---|---|---|
| Patent Prescription | US20190113711A1 · 11 elements in 9 groups (1 aspherical) | Traced surface by surface in WebGL2 |
| Entrance Pupil Diameter | 19.4 mm (at f/1.8) | Controls distant background blur disc size |
| Upper-Body Working Distance | 1.42 m | Camera-to-subject distance for head-to-waist framing |
| Effective Focal Length (Breathing) | 34.8 mm (-0.5%) | Actual framing focal length at portrait distance |
| Depth of Field (Sharp Zone) | 26 cm (1.30 m – 1.56 m) | Sharp zone at wide-open aperture |
| Minimum Focus Distance | 0.17 m | Closest focusing distance from the sensor |
Questions
How much background blur does the Canon RF 35mm F1.8 MACRO IS STM produce?
Wide open at f/1.8, the Canon RF 35mm F1.8 MACRO IS STM has a 19.4 mm entrance pupil (35 mm ÷ 1.8). In an upper-body portrait at 1.42 m, the sharp depth-of-field zone spans 26 cm (1.30 m to 1.56 m), while mechanical vignetting and 11 glass elements shape the out-of-focus highlights.
Does the Canon RF 35mm F1.8 MACRO IS STM show focus breathing at portrait distance?
Based on patent US20190113711A1, tracing the focusing group at 1.42 m gives an effective framing focal length of 34.8 mm (-0.5% vs. the nominal 35 mm). You can toggle "Match subject size" in the simulator to see the framing shift live.
What optical design is inside the Canon RF 35mm F1.8 MACRO IS STM?
The patent prescription (US20190113711A1) specifies 11 lens elements in 9 groups with 1 aspherical surfaces. The interactive Optical X-Ray above traces rays through every surface in real time.
Head-to-head patent comparisons with Canon RF 35mm F1.8 MACRO IS STM
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Also see: depth of field, bokeh, crop factor, lens compression.