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Leica DG Summilux 12mm f/1.4 ASPH. — Bokeh & Optical Ray-Tracing Simulator
Interactive 3D portrait ray-traced through the published JP2017-167327A optical prescription (15 elements in 12 groups, 2 aspherical) with a 8.6 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 | JP2017-167327A · 15 elements in 12 groups (2 aspherical) | Traced surface by surface in WebGL2 |
| Entrance Pupil Diameter | 8.6 mm (at f/1.4) | Controls distant background blur disc size |
| Corner Bokeh Roundness (90% Field) | 83% at f/1.4 (≥86% from f/1.8) · -0.4 EV | Mechanical vignetting (cat’s-eye vs. round corner highlights) |
| Background Field of View (Compression) | 76° horizontal | Width of the background room visible behind the subject |
| Upper-Body Working Distance | 1.03 m | Camera-to-subject distance for head-to-waist framing |
| Effective Focal Length (Breathing) | 11.1 mm (-7.1%) | Actual framing focal length at portrait distance |
| Depth of Field (Sharp Zone) | 46 cm (85 cm – 1.31 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 12mm f/1.4 ASPH. produce?
Wide open at f/1.4, the Leica DG Summilux 12mm f/1.4 ASPH. has a 8.6 mm entrance pupil (12 mm ÷ 1.4) and 83% bokeh roundness in the 90% corner (-0.4 EV corner falloff, reaching ≥86% roundness from f/1.8). In an upper-body portrait at 1.03 m, the sharp depth-of-field zone spans 46 cm (85 cm to 1.31 m) with a 76° horizontal background angle of view.
Does the Leica DG Summilux 12mm f/1.4 ASPH. show focus breathing at portrait distance?
Based on patent JP2017-167327A, tracing the focusing group at 1.03 m gives an effective framing focal length of 11.1 mm (-7.1% vs. the nominal 12 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 12mm f/1.4 ASPH.?
The patent prescription (JP2017-167327A) specifies 15 lens elements in 12 groups with 2 aspherical surfaces. The interactive Optical X-Ray above traces rays through every surface in real time.
Related comparisons
- Leica DG Summilux 15mm f/1.7 ASPH.
- Leica DG Summilux 9mm f/1.7 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
Compare with similar portrait lenses
- Canon RF 14mm F1.4 L VCM
- Sony FE 14mm F1.8 GM
- Fujifilm XF 16mm F1.4 R WR
- Sony E 20mm F2.8
- Nikon 20mm f/2.8 AI-s
Also see: depth of field, bokeh, crop factor, lens compression.