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Leica Macro-Elmar-M 90mm f/4 — Bokeh & Optical Ray-Tracing Simulator
Interactive 3D portrait ray-traced through the published DE2246966A1 optical prescription (4 elements in 4 groups) with a 22.5 mm entrance pupil and 0.77 m minimum focus.
Optical & Portrait Specifications (Upper Body Framing)
| Optical & Portrait Metric | Measured / Patent Value | What It Means in Practice |
|---|---|---|
| Patent Prescription | DE2246966A1 · 4 elements in 4 groups | Traced surface by surface in WebGL2 |
| Entrance Pupil Diameter | 22.5 mm (at f/4) | Controls distant background blur disc size |
| Corner Bokeh Roundness (90% Field) | 88% at f/4 · -0.2 EV | Mechanical vignetting (cat’s-eye vs. round corner highlights) |
| Background Field of View (Compression) | 22° horizontal | Width of the background room visible behind the subject |
| Upper-Body Working Distance | 3.61 m | Camera-to-subject distance for head-to-waist framing |
| Effective Focal Length (Breathing) | 93.6 mm (+4.0%) | Actual framing focal length at portrait distance |
| Depth of Field (Sharp Zone) | 57 cm (3.35 m – 3.91 m) | Sharp zone at wide-open aperture |
| Minimum Focus Distance | 0.77 m | Closest focusing distance from the sensor |
Questions
How much background blur and corner cat's-eye does the Leica Macro-Elmar-M 90mm f/4 produce?
Wide open at f/4, the Leica Macro-Elmar-M 90mm f/4 has a 22.5 mm entrance pupil (90 mm ÷ 4) and 88% bokeh roundness in the 90% corner (-0.2 EV corner falloff). In an upper-body portrait at 3.61 m, the sharp depth-of-field zone spans 57 cm (3.35 m to 3.91 m) with a 22° horizontal background angle of view.
Does the Leica Macro-Elmar-M 90mm f/4 show focus breathing at portrait distance?
Based on patent DE2246966A1, tracing the focusing group at 3.61 m gives an effective framing focal length of 93.6 mm (+4.0% vs. the nominal 90 mm). You can toggle "Match subject size" in the simulator to see the framing shift live.
What optical design is inside the Leica Macro-Elmar-M 90mm f/4?
The patent prescription (DE2246966A1) specifies 4 lens elements in 4 groups. The interactive Optical X-Ray above traces rays through every surface in real time.
Related comparisons
- Leica Summilux-M 90mm f/1.5 ASPH.
- Leica APO-Summicron-M 90mm f/2 ASPH.
- Leica TELE-ELMARIT-M 90mm f/2.8
- 35mm vs 85mm focal length comparison
- 40mm vs 85mm focal length comparison
- 50mm vs 85mm focal length comparison
Compare with similar portrait lenses
- Sony FE 90mm F2.8 Macro G OSS
- Nikon Nikkor SW 90mm f/4.5
- Nikon 85mm f/2.8 PC-E FX
- Nikon 85mm f/3.5 VR DX
- Fujifilm GF 63mm F2.8 R WR
Also see: depth of field, bokeh, crop factor, lens compression.