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Fujifilm XF 18mm F1.4 R LM WR — Bokeh & Optical Ray-Tracing Simulator
Interactive 3D portrait ray-traced through the published US20220011542A1 optical prescription (15 elements in 9 groups, 5 aspherical) with a 12.9 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 | US20220011542A1 · 15 elements in 9 groups (5 aspherical) | Traced surface by surface in WebGL2 |
| Entrance Pupil Diameter | 12.9 mm (at f/1.4) | Controls distant background blur disc size |
| Corner Bokeh Roundness (90% Field) | 80% at f/1.4 (≥86% from f/1.8) · -0.7 EV | Mechanical vignetting (cat’s-eye vs. round corner highlights) |
| Background Field of View (Compression) | 66° horizontal | Width of the background room visible behind the subject |
| Upper-Body Working Distance | 1.13 m | Camera-to-subject distance for head-to-waist framing |
| Effective Focal Length (Breathing) | 18.0 mm (+0.3%) | Actual framing focal length at portrait distance |
| Depth of Field (Sharp Zone) | 32 cm (99 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 Fujifilm XF 18mm F1.4 R LM WR produce?
Wide open at f/1.4, the Fujifilm XF 18mm F1.4 R LM WR has a 12.9 mm entrance pupil (18 mm ÷ 1.4) and 80% bokeh roundness in the 90% corner (-0.7 EV corner falloff, reaching ≥86% roundness from f/1.8). In an upper-body portrait at 1.13 m, the sharp depth-of-field zone spans 32 cm (99 cm to 1.31 m) with a 66° horizontal background angle of view.
Does the Fujifilm XF 18mm F1.4 R LM WR show focus breathing at portrait distance?
Based on patent US20220011542A1, tracing the focusing group at 1.13 m gives an effective framing focal length of 18.0 mm (+0.3% vs. the nominal 18 mm). You can toggle "Match subject size" in the simulator to see the framing shift live.
What optical design is inside the Fujifilm XF 18mm F1.4 R LM WR?
The patent prescription (US20220011542A1) specifies 15 lens elements in 9 groups with 5 aspherical surfaces. The interactive Optical X-Ray above traces rays through every surface in real time.
Related comparisons
- Fujifilm XF 18mm F1.4 R LM WR vs. Fujifilm XF 18mm F2 R
- Fujifilm XF 18mm F1.4 R LM WR vs. Fujifilm XF 23mm F1.4 R LM WR
- Fujifilm XF 18mm F2 R
- Fujifilm XF 16mm F1.4 R WR
- Fujifilm XF 16mm F2.8 R WR
- Fujifilm XF 14mm F2.8 R
Compare with similar portrait lenses
Also see: depth of field, bokeh, crop factor, lens compression.