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Nikon 300mm f/2 ED IF — Bokeh & Optical Ray-Tracing Simulator
Interactive 3D portrait ray-traced through the published US4732459A optical prescription (11 elements in 8 groups) with a 150.0 mm entrance pupil and 4 m minimum focus.
Optical & Portrait Specifications (Upper Body Framing)
| Optical & Portrait Metric | Measured / Patent Value | What It Means in Practice |
|---|---|---|
| Patent Prescription | US4732459A · 11 elements in 8 groups | Traced surface by surface in WebGL2 |
| Entrance Pupil Diameter | 150.0 mm (at f/2) | Controls distant background blur disc size |
| Corner Bokeh Roundness (90% Field) | 82% at f/2 (≥86% from f/2.8) · -0.3 EV | Mechanical vignetting (cat’s-eye vs. round corner highlights) |
| Background Field of View (Compression) | 7° horizontal | Width of the background room visible behind the subject |
| Upper-Body Working Distance | 12.00 m | Camera-to-subject distance for head-to-waist framing |
| Effective Focal Length (Breathing) | 303.9 mm (+1.3%) | Actual framing focal length at portrait distance |
| Depth of Field (Sharp Zone) | 28 cm (12 m – 12 m) | Sharp zone at wide-open aperture |
| Minimum Focus Distance | 4 m | Closest focusing distance from the sensor |
Questions
How much background blur and corner cat's-eye does the Nikon 300mm f/2 ED IF produce?
Wide open at f/2, the Nikon 300mm f/2 ED IF has a 150.0 mm entrance pupil (300 mm ÷ 2) and 82% bokeh roundness in the 90% corner (-0.3 EV corner falloff, reaching ≥86% roundness from f/2.8). In an upper-body portrait at 12.00 m, the sharp depth-of-field zone spans 28 cm (12 m to 12 m) with a 7° horizontal background angle of view.
Does the Nikon 300mm f/2 ED IF show focus breathing at portrait distance?
Based on patent US4732459A, tracing the focusing group at 12.00 m gives an effective framing focal length of 303.9 mm (+1.3% vs. the nominal 300 mm). You can toggle "Match subject size" in the simulator to see the framing shift live.
What optical design is inside the Nikon 300mm f/2 ED IF?
The patent prescription (US4732459A) specifies 11 lens elements in 8 groups. The interactive Optical X-Ray above traces rays through every surface in real time.
Related comparisons
- Nikon 300mm f/2.8 AF-S II FX
- Nikon 300mm f/4.5 ED-IF AI-s
- 50mm vs 200mm focal length comparison
- 70mm vs 200mm focal length comparison
- 85mm vs 200mm focal length comparison
- 105mm vs 200mm focal length comparison
Compare with similar portrait lenses
- Sony FE 300mm F2.8 GM OSS
- Canon 300mm f/2.8 L IS
- Leica APO-Telyt-R 280mm f/2.8
- Canon 300mm f/4 L IS
- Nikon NIKKOR Z 400mm f/2.8 TC VR S
Also see: depth of field, bokeh, crop factor, lens compression.