Nikon Nikkor-S Auto 58mm f/1.4 — Bokeh & Optical Ray-Tracing Simulator

Interactive 3D portrait ray-traced through the published JP S41-017177B optical prescription (7 elements in 6 groups) with a 41.4 mm entrance pupil and 0.6 m minimum focus.

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Optical & Portrait Specifications (Upper Body Framing)

Optical & Portrait Metric Measured / Patent Value What It Means in Practice
Patent Prescription JP S41-017177B · 7 elements in 6 groups Traced surface by surface in WebGL2
Entrance Pupil Diameter 41.4 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) · -0.4 EV Mechanical vignetting (cat’s-eye vs. round corner highlights)
Background Field of View (Compression) 34° horizontal Width of the background room visible behind the subject
Upper-Body Working Distance 2.33 m Camera-to-subject distance for head-to-waist framing
Effective Focal Length (Breathing) 58.3 mm (+0.5%) Actual framing focal length at portrait distance
Depth of Field (Sharp Zone) 20 cm (2.24 m – 2.44 m) Sharp zone at wide-open aperture
Minimum Focus Distance 0.6 m Closest focusing distance from the sensor

Questions

How much background blur and corner cat's-eye does the Nikon Nikkor-S Auto 58mm f/1.4 produce?

Wide open at f/1.4, the Nikon Nikkor-S Auto 58mm f/1.4 has a 41.4 mm entrance pupil (58 mm ÷ 1.4) and 80% bokeh roundness in the 90% corner (-0.4 EV corner falloff, reaching ≥86% roundness from f/1.8). In an upper-body portrait at 2.33 m, the sharp depth-of-field zone spans 20 cm (2.24 m to 2.44 m) with a 34° horizontal background angle of view.

Does the Nikon Nikkor-S Auto 58mm f/1.4 show focus breathing at portrait distance?

Based on patent JP S41-017177B, tracing the focusing group at 2.33 m gives an effective framing focal length of 58.3 mm (+0.5% vs. the nominal 58 mm). You can toggle "Match subject size" in the simulator to see the framing shift live.

What optical design is inside the Nikon Nikkor-S Auto 58mm f/1.4?

The patent prescription (JP S41-017177B) specifies 7 lens elements in 6 groups. The interactive Optical X-Ray above traces rays through every surface in real time.

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Also see: depth of field, bokeh, crop factor, lens compression.