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Nikon 24mm f/2.0 AI-s — Bokeh & Optical Ray-Tracing Simulator
Interactive 3D portrait ray-traced through the published US4163603A optical prescription (11 elements in 10 groups) with a 12.0 mm entrance pupil and 0.3 m minimum focus.
Optical & Portrait Specifications (Upper Body Framing)
| Optical & Portrait Metric | Measured / Patent Value | What It Means in Practice |
|---|---|---|
| Patent Prescription | US4163603A · 11 elements in 10 groups | Traced surface by surface in WebGL2 |
| Entrance Pupil Diameter | 12.0 mm (at f/2) | Controls distant background blur disc size |
| Corner Bokeh Roundness (90% Field) | 53% at f/2 (≥86% from f/4) · -1.5 EV | Mechanical vignetting (cat’s-eye vs. round corner highlights) |
| Background Field of View (Compression) | 75° horizontal | Width of the background room visible behind the subject |
| Upper-Body Working Distance | 0.99 m | Camera-to-subject distance for head-to-waist framing |
| Effective Focal Length (Breathing) | 23.4 mm (-2.4%) | Actual framing focal length at portrait distance |
| Depth of Field (Sharp Zone) | 30 cm (86 cm – 1.17 m) | Sharp zone at wide-open aperture |
| Minimum Focus Distance | 0.3 m | Closest focusing distance from the sensor |
Questions
How much background blur and corner cat's-eye does the Nikon 24mm f/2.0 AI-s produce?
Wide open at f/2, the Nikon 24mm f/2.0 AI-s has a 12.0 mm entrance pupil (24 mm ÷ 2) and 53% bokeh roundness in the 90% corner (-1.5 EV corner falloff, reaching ≥86% roundness from f/4). In an upper-body portrait at 0.99 m, the sharp depth-of-field zone spans 30 cm (86 cm to 1.17 m) with a 75° horizontal background angle of view.
Does the Nikon 24mm f/2.0 AI-s show focus breathing at portrait distance?
Based on patent US4163603A, tracing the focusing group at 0.99 m gives an effective framing focal length of 23.4 mm (-2.4% vs. the nominal 24 mm). You can toggle "Match subject size" in the simulator to see the framing shift live.
What optical design is inside the Nikon 24mm f/2.0 AI-s?
The patent prescription (US4163603A) specifies 11 lens elements in 10 groups. The interactive Optical X-Ray above traces rays through every surface in real time.
Related comparisons
- Nikon 24mm f/1.4G FX
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- Nikon Nikkor-O 2.1cm f/4
- Nikon 28mm f/1.4E FX
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Also see: depth of field, bokeh, crop factor, lens compression.