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Leica DG Summilux 9mm f/1.7 ASPH. — Bokeh & Optical Ray-Tracing Simulator
Interactive 3D portrait ray-traced through the published US20230367186A1 optical prescription (15 elements in 9 groups, 4 aspherical) with a 5.3 mm entrance pupil and 0.1 m minimum focus.
Optical & Portrait Specifications (Upper Body Framing)
| Optical & Portrait Metric | Measured / Patent Value | What It Means in Practice |
|---|---|---|
| Patent Prescription | US20230367186A1 · 15 elements in 9 groups (4 aspherical) | Traced surface by surface in WebGL2 |
| Entrance Pupil Diameter | 5.3 mm (at f/1.7) | Controls distant background blur disc size |
| Corner Bokeh Roundness (90% Field) | 73% at f/1.7 (≥86% from f/2.8) · -0.7 EV | Mechanical vignetting (cat’s-eye vs. round corner highlights) |
| Background Field of View (Compression) | 93° horizontal | Width of the background room visible behind the subject |
| Upper-Body Working Distance | 0.79 m | Camera-to-subject distance for head-to-waist framing |
| Effective Focal Length (Breathing) | 8.2 mm (-8.3%) | Actual framing focal length at portrait distance |
| Depth of Field (Sharp Zone) | 63 cm (58 cm – 1.21 m) | Sharp zone at wide-open aperture |
| Minimum Focus Distance | 0.1 m | Closest focusing distance from the sensor |
Questions
How much background blur and corner cat's-eye does the Leica DG Summilux 9mm f/1.7 ASPH. produce?
Wide open at f/1.7, the Leica DG Summilux 9mm f/1.7 ASPH. has a 5.3 mm entrance pupil (9 mm ÷ 1.7) and 73% bokeh roundness in the 90% corner (-0.7 EV corner falloff, reaching ≥86% roundness from f/2.8). In an upper-body portrait at 0.79 m, the sharp depth-of-field zone spans 63 cm (58 cm to 1.21 m) with a 93° horizontal background angle of view.
Does the Leica DG Summilux 9mm f/1.7 ASPH. show focus breathing at portrait distance?
Based on patent US20230367186A1, tracing the focusing group at 0.79 m gives an effective framing focal length of 8.2 mm (-8.3% vs. the nominal 9 mm). You can toggle "Match subject size" in the simulator to see the framing shift live.
What optical design is inside the Leica DG Summilux 9mm f/1.7 ASPH.?
The patent prescription (US20230367186A1) specifies 15 lens elements in 9 groups with 4 aspherical surfaces. The interactive Optical X-Ray above traces rays through every surface in real time.
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Compare with similar portrait lenses
- Nikon 10.5mm f/2.8G ED DX Fisheye
- Canon 15mm f/2.8 Fisheye
- Canon 14mm f/2.8 L II
- Fujifilm XF 14mm F2.8 R
Also see: depth of field, bokeh, crop factor, lens compression.