Interactive 3D portrait ray-traced through the published US4908639A optical prescription (7 elements in 6 groups) with a 67.5 mm entrance pupil and 1.1 m minimum focus.
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| Optical & Portrait Metric | Measured / Patent Value | What It Means in Practice |
|---|---|---|
| Patent Prescription | US4908639A · 7 elements in 6 groups | Traced surface by surface in WebGL2 |
| Entrance Pupil Diameter | 67.5 mm (at f/2) | Controls distant background blur disc size |
| Upper-Body Working Distance | 5.40 m | Camera-to-subject distance for head-to-waist framing |
| Effective Focal Length (Breathing) | 131.0 mm (-3.0%) | Actual framing focal length at portrait distance |
| Depth of Field (Sharp Zone) | 28 cm (5.27 m – 5.55 m) | Sharp zone at wide-open aperture |
| Minimum Focus Distance | 1.1 m | Closest focusing distance from the sensor |
Wide open at f/2, the Nikon AF DC 135mm f/2D has a 67.5 mm entrance pupil (135 mm ÷ 2). In an upper-body portrait at 5.40 m, the sharp depth-of-field zone spans 28 cm (5.27 m to 5.55 m), while mechanical vignetting and 7 glass elements shape the out-of-focus highlights.
Based on patent US4908639A, tracing the focusing group at 5.40 m gives an effective framing focal length of 131.0 mm (-3.0% vs. the nominal 135 mm). You can toggle "Match subject size" in the simulator to see the framing shift live.
The patent prescription (US4908639A) specifies 7 lens elements in 6 groups. The interactive Optical X-Ray above traces rays through every surface in real time.
Wszystkie porównania obiektywów
Zobacz też: głębia ostrości, bokeh, współczynnik crop, kompresja.
