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Leica DG Summilux 15mm f/1.7 ASPH. — Bokeh & Optical Ray-Tracing Simulator
Interactive 3D portrait ray-traced through the published US20150268449A1 optical prescription (9 elements in 7 groups, 5 aspherical) with a 8.8 mm entrance pupil and 0.2 m minimum focus.
Optical & Portrait Specifications (Upper Body Framing)
| Optical & Portrait Metric | Measured / Patent Value | What It Means in Practice |
|---|---|---|
| Patent Prescription | US20150268449A1 · 9 elements in 7 groups (5 aspherical) | Traced surface by surface in WebGL2 |
| Entrance Pupil Diameter | 8.8 mm (at f/1.7) | Controls distant background blur disc size |
| Corner Bokeh Roundness (90% Field) | 54% at f/1.7 (≥86% from f/4) · -1.4 EV | Mechanical vignetting (cat’s-eye vs. round corner highlights) |
| Background Field of View (Compression) | 63° horizontal | Width of the background room visible behind the subject |
| Upper-Body Working Distance | 1.27 m | Camera-to-subject distance for head-to-waist framing |
| Effective Focal Length (Breathing) | 14.3 mm (-5.0%) | Actual framing focal length at portrait distance |
| Depth of Field (Sharp Zone) | 54 cm (1.06 m – 1.60 m) | Sharp zone at wide-open aperture |
| Minimum Focus Distance | 0.2 m | Closest focusing distance from the sensor |
Questions
How much background blur and corner cat's-eye does the Leica DG Summilux 15mm f/1.7 ASPH. produce?
Wide open at f/1.7, the Leica DG Summilux 15mm f/1.7 ASPH. has a 8.8 mm entrance pupil (15 mm ÷ 1.7) and 54% bokeh roundness in the 90% corner (-1.4 EV corner falloff, reaching ≥86% roundness from f/4). In an upper-body portrait at 1.27 m, the sharp depth-of-field zone spans 54 cm (1.06 m to 1.60 m) with a 63° horizontal background angle of view.
Does the Leica DG Summilux 15mm f/1.7 ASPH. show focus breathing at portrait distance?
Based on patent US20150268449A1, tracing the focusing group at 1.27 m gives an effective framing focal length of 14.3 mm (-5.0% vs. the nominal 15 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 15mm f/1.7 ASPH.?
The patent prescription (US20150268449A1) specifies 9 lens elements in 7 groups with 5 aspherical surfaces. The interactive Optical X-Ray above traces rays through every surface in real time.
Related comparisons
- Leica DG Summilux 12mm f/1.4 ASPH.
- 23mm APS-C vs 35mm full frame focal length comparison
- 24mm vs 35mm focal length comparison
- 24mm vs 50mm focal length comparison
- 28mm vs 35mm focal length comparison
- 28mm vs 50mm focal length comparison
Compare with similar portrait lenses
- Sony FE 14mm F1.8 GM
- Canon RF 14mm F1.4 L VCM
- Canon 15mm f/2.8 Fisheye
- Fujifilm XF 16mm F1.4 R WR
- Nikon 16mm f/2.8 AI-s Fisheye
Also see: depth of field, bokeh, crop factor, lens compression.