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Sigma 50mm F1.4 DG DN | Art — Bokeh & Optical Ray-Tracing Simulator
Interactive 3D portrait ray-traced through the published JP 2023-183894 A optical prescription (14 elements in 11 groups, 5 aspherical) with a 35.7 mm entrance pupil and 0.45 m minimum focus.
Optical & Portrait Specifications (Upper Body Framing)
| Optical & Portrait Metric | Measured / Patent Value | What It Means in Practice |
|---|---|---|
| Patent Prescription | JP 2023-183894 A · 14 elements in 11 groups (5 aspherical) | Traced surface by surface in WebGL2 |
| Entrance Pupil Diameter | 35.7 mm (at f/1.4) | Controls distant background blur disc size |
| Corner Bokeh Roundness (90% Field) | 48% at f/1.4 (≥86% from f/4) · -1.4 EV | Mechanical vignetting (cat’s-eye vs. round corner highlights) |
| Background Field of View (Compression) | 38° horizontal | Width of the background room visible behind the subject |
| Upper-Body Working Distance | 2.01 m | Camera-to-subject distance for head-to-waist framing |
| Effective Focal Length (Breathing) | 51.9 mm (+3.7%) | Actual framing focal length at portrait distance |
| Depth of Field (Sharp Zone) | 20 cm (1.92 m – 2.12 m) | Sharp zone at wide-open aperture |
| Minimum Focus Distance | 0.45 m | Closest focusing distance from the sensor |
Questions
How much background blur and corner cat's-eye does the Sigma 50mm F1.4 DG DN | Art produce?
Wide open at f/1.4, the Sigma 50mm F1.4 DG DN | Art has a 35.7 mm entrance pupil (50 mm ÷ 1.4) and 48% bokeh roundness in the 90% corner (-1.4 EV corner falloff, reaching ≥86% roundness from f/4). In an upper-body portrait at 2.01 m, the sharp depth-of-field zone spans 20 cm (1.92 m to 2.12 m) with a 38° horizontal background angle of view.
Does the Sigma 50mm F1.4 DG DN | Art show focus breathing at portrait distance?
Based on patent JP 2023-183894 A, tracing the focusing group at 2.01 m gives an effective framing focal length of 51.9 mm (+3.7% vs. the nominal 50 mm). You can toggle "Match subject size" in the simulator to see the framing shift live.
What optical design is inside the Sigma 50mm F1.4 DG DN | Art?
The patent prescription (JP 2023-183894 A) specifies 14 lens elements in 11 groups with 5 aspherical surfaces. The interactive Optical X-Ray above traces rays through every surface in real time.
Related comparisons
- Sigma 50mm F1.2 DG DN | Art
- Sigma 56mm F1.4 DC DN | Contemporary
- 24mm vs 50mm focal length comparison
- 28mm vs 50mm focal length comparison
- 35mm vs 50mm focal length comparison
- 40mm vs 50mm focal length comparison
Compare with similar portrait lenses
- Sony FE 50mm F1.4 GM
- Sony Planar FE 50mm F1.4 ZA
- Nikon NIKKOR Z 50mm f/1.4
- Nikon AF-S 50mm f/1.4G
- Nikon 50mm f/1.4 AI-s
- Leica Summicron-M 66mm f/2
Also see: depth of field, bokeh, crop factor, lens compression.