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Leica Elmarit-M 28mm f/2.8 ASPH. — Bokeh & Optical Ray-Tracing Simulator
Interactive 3D portrait ray-traced through the published US3591257A optical prescription (8 elements in 6 groups) with a 10.0 mm entrance pupil and 0.7 m minimum focus.
Optical & Portrait Specifications (Upper Body Framing)
| Optical & Portrait Metric | Measured / Patent Value | What It Means in Practice |
|---|---|---|
| Patent Prescription | US3591257A · 8 elements in 6 groups | Traced surface by surface in WebGL2 |
| Entrance Pupil Diameter | 10.0 mm (at f/2.8) | Controls distant background blur disc size |
| Corner Bokeh Roundness (90% Field) | 67% at f/2.8 (≥86% from f/4) · -0.8 EV | Mechanical vignetting (cat’s-eye vs. round corner highlights) |
| Background Field of View (Compression) | 64° horizontal | Width of the background room visible behind the subject |
| Upper-Body Working Distance | 1.15 m | Camera-to-subject distance for head-to-waist framing |
| Effective Focal Length (Breathing) | 28.6 mm (+2.3%) | Actual framing focal length at portrait distance |
| Depth of Field (Sharp Zone) | 42 cm (97 cm – 1.40 m) | Sharp zone at wide-open aperture |
| Minimum Focus Distance | 0.7 m | Closest focusing distance from the sensor |
Questions
How much background blur and corner cat's-eye does the Leica Elmarit-M 28mm f/2.8 ASPH. produce?
Wide open at f/2.8, the Leica Elmarit-M 28mm f/2.8 ASPH. has a 10.0 mm entrance pupil (28 mm ÷ 2.8) and 67% bokeh roundness in the 90% corner (-0.8 EV corner falloff, reaching ≥86% roundness from f/4). In an upper-body portrait at 1.15 m, the sharp depth-of-field zone spans 42 cm (97 cm to 1.40 m) with a 64° horizontal background angle of view.
Does the Leica Elmarit-M 28mm f/2.8 ASPH. show focus breathing at portrait distance?
Based on patent US3591257A, tracing the focusing group at 1.15 m gives an effective framing focal length of 28.6 mm (+2.3% vs. the nominal 28 mm). You can toggle "Match subject size" in the simulator to see the framing shift live.
What optical design is inside the Leica Elmarit-M 28mm f/2.8 ASPH.?
The patent prescription (US3591257A) specifies 8 lens elements in 6 groups. The interactive Optical X-Ray above traces rays through every surface in real time.
Related comparisons
- Leica Summilux-M 28mm f/1.4 ASPH.
- Leica Summicron-M 28mm f/2 ASPH.
- Leica ELMARIT-M 24mm f/2.8 ASPH
- Leica Summilux-M 35mm f/1.4
- Leica Summilux-M 35mm f/1.4 ASPH.
- Leica Summilux-M 35mm f/1.4 Pre-ASPH
Compare with similar portrait lenses
- Nikon NIKKOR Z 28mm f/2.8
- Nikon 28mm f/2.8 AI-s
- Nikon AF 28mm f/2.8D
- Canon RF 28mm F2.8 STM
- Nikon 28mm f/3.5
- Canon EF-M 22mm f/2 STM
Also see: depth of field, bokeh, crop factor, lens compression.