Interactive 3D portrait ray-traced through the published JP H05-157964A optical prescription (9 elements in 7 groups) with a 47.2 mm entrance pupil and 0.85 m minimum focus.
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| Optical & Portrait Metric | Measured / Patent Value | What It Means in Practice |
|---|---|---|
| Patent Prescription | JP H05-157964A · 9 elements in 7 groups | Traced surface by surface in WebGL2 |
| Entrance Pupil Diameter | 47.2 mm (at f/1.8) | Controls distant background blur disc size |
| Upper-Body Working Distance | 3.41 m | Camera-to-subject distance for head-to-waist framing |
| Effective Focal Length (Breathing) | 86.0 mm (+1.1%) | Actual framing focal length at portrait distance |
| Depth of Field (Sharp Zone) | 25 cm (3.29 m – 3.54 m) | Sharp zone at wide-open aperture |
| Minimum Focus Distance | 0.85 m | Closest focusing distance from the sensor |
Wide open at f/1.8, the Canon 85mm f/1.8 has a 47.2 mm entrance pupil (85 mm ÷ 1.8). In an upper-body portrait at 3.41 m, the sharp depth-of-field zone spans 25 cm (3.29 m to 3.54 m), while mechanical vignetting and 9 glass elements shape the out-of-focus highlights.
Based on patent JP H05-157964A, tracing the focusing group at 3.41 m gives an effective framing focal length of 86.0 mm (+1.1% vs. the nominal 85 mm). You can toggle "Match subject size" in the simulator to see the framing shift live.
The patent prescription (JP H05-157964A) specifies 9 lens elements in 7 groups. The interactive Optical X-Ray above traces rays through every surface in real time.
Zie ook: scherptediepte, bokeh, cropfactor, compressie.
