Find a lens for this look
eBay links may earn us a commission, at no extra cost to you.
Matching lenses from each maker's lineup, plus some classic medium and large format lenses. Email me if something is wrong or missing.
Pentax HD PENTAX-D FA ★ 85mm F1.4 ED SDM AW — Bokeh & Optical Ray-Tracing Simulator
Interactive 3D portrait ray-traced through the published US 2020/0301101 A1 optical prescription (12 elements in 10 groups, 2 aspherical) with a 60.7 mm entrance pupil and 0.85 m minimum focus.
Optical & Portrait Specifications (Upper Body Framing)
| Optical & Portrait Metric | Measured / Patent Value | What It Means in Practice |
|---|---|---|
| Patent Prescription | US 2020/0301101 A1 · 12 elements in 10 groups (2 aspherical) | Traced surface by surface in WebGL2 |
| Entrance Pupil Diameter | 60.7 mm (at f/1.4) | Controls distant background blur disc size |
| Corner Bokeh Roundness (90% Field) | 73% 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) | 23° horizontal | Width of the background room visible behind the subject |
| Upper-Body Working Distance | 3.41 m | Camera-to-subject distance for head-to-waist framing |
| Effective Focal Length (Breathing) | 87.7 mm (+3.1%) | Actual framing focal length at portrait distance |
| Depth of Field (Sharp Zone) | 20 cm (3.31 m – 3.51 m) | Sharp zone at wide-open aperture |
| Minimum Focus Distance | 0.85 m | Closest focusing distance from the sensor |
Questions
How much background blur and corner cat's-eye does the Pentax HD PENTAX-D FA ★ 85mm F1.4 ED SDM AW produce?
Wide open at f/1.4, the Pentax HD PENTAX-D FA ★ 85mm F1.4 ED SDM AW has a 60.7 mm entrance pupil (85 mm ÷ 1.4) and 73% bokeh roundness in the 90% corner (-0.7 EV corner falloff, reaching ≥86% roundness from f/1.8). In an upper-body portrait at 3.41 m, the sharp depth-of-field zone spans 20 cm (3.31 m to 3.51 m) with a 23° horizontal background angle of view.
Does the Pentax HD PENTAX-D FA ★ 85mm F1.4 ED SDM AW show focus breathing at portrait distance?
Based on patent US 2020/0301101 A1, tracing the focusing group at 3.41 m gives an effective framing focal length of 87.7 mm (+3.1% vs. the nominal 85 mm). You can toggle "Match subject size" in the simulator to see the framing shift live.
What optical design is inside the Pentax HD PENTAX-D FA ★ 85mm F1.4 ED SDM AW?
The patent prescription (US 2020/0301101 A1) specifies 12 lens elements in 10 groups with 2 aspherical surfaces. The interactive Optical X-Ray above traces rays through every surface in real time.
Related comparisons
- 35mm vs 85mm focal length comparison
- 40mm vs 85mm focal length comparison
- 50mm vs 85mm focal length comparison
- 58mm vs 85mm focal length comparison
- 70mm vs 85mm focal length comparison
- 85mm vs 105mm focal length comparison
Compare with similar portrait lenses
- Sony FE 85mm F1.4 GM II
- Sony FE 85mm F1.4 GM
- Nikon 85mm f/1.4 G FX
- Nikon 85mm f/1.4 AI-s
- Nikon AF 85mm f/1.4D IF
- Nikon 105mm f/1.8 AI-s
Also see: depth of field, bokeh, crop factor, lens compression.