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Sony Sonnar FE 55mm F1.8 ZA — Bokeh & Optical Ray-Tracing Simulator
Interactive 3D portrait ray-traced through the published US20150092100A1 optical prescription (7 elements in 5 groups, 5 aspherical) with a 30.6 mm entrance pupil and 0.5 m minimum focus.
Optical & Portrait Specifications (Upper Body Framing)
| Optical & Portrait Metric | Measured / Patent Value | What It Means in Practice |
|---|---|---|
| Patent Prescription | US20150092100A1 · 7 elements in 5 groups (5 aspherical) | Traced surface by surface in WebGL2 |
| Entrance Pupil Diameter | 30.6 mm (at f/1.8) | Controls distant background blur disc size |
| Upper-Body Working Distance | 2.21 m | Camera-to-subject distance for head-to-waist framing |
| Effective Focal Length (Breathing) | 54.2 mm (-1.5%) | Actual framing focal length at portrait distance |
| Depth of Field (Sharp Zone) | 26 cm (2.09 m – 2.35 m) | Sharp zone at wide-open aperture |
| Minimum Focus Distance | 0.5 m | Closest focusing distance from the sensor |
Questions
How much background blur does the Sony Sonnar FE 55mm F1.8 ZA produce?
Wide open at f/1.8, the Sony Sonnar FE 55mm F1.8 ZA has a 30.6 mm entrance pupil (55 mm ÷ 1.8). In an upper-body portrait at 2.21 m, the sharp depth-of-field zone spans 26 cm (2.09 m to 2.35 m), while mechanical vignetting and 7 glass elements shape the out-of-focus highlights.
Does the Sony Sonnar FE 55mm F1.8 ZA show focus breathing at portrait distance?
Based on patent US20150092100A1, tracing the focusing group at 2.21 m gives an effective framing focal length of 54.2 mm (-1.5% vs. the nominal 55 mm). You can toggle "Match subject size" in the simulator to see the framing shift live.
What optical design is inside the Sony Sonnar FE 55mm F1.8 ZA?
The patent prescription (US20150092100A1) specifies 7 lens elements in 5 groups with 5 aspherical surfaces. The interactive Optical X-Ray above traces rays through every surface in real time.
Head-to-head patent comparisons with Sony Sonnar FE 55mm F1.8 ZA
- Sony Sonnar FE 55mm F1.8 ZA vs. Sony FE 50mm F1.8
- Sony Sonnar FE 55mm F1.8 ZA vs. Sony FE 50mm F1.2 GM
- Sony Sonnar FE 55mm F1.8 ZA vs. Sony Planar FE 50mm F1.4 ZA
Related comparisons
- Sony FE 50mm F1.8
- Nikon NIKKOR Z 50mm f/1.8 S
- Canon RF 50mm F1.8 STM
- Sony FE 90mm F2.8 Macro G OSS
- Nikon NIKKOR Z 35mm f/1.2 S
Also see: depth of field, bokeh, crop factor, lens compression.