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Matching lenses from each maker's lineup, plus some classic medium and large format lenses. Email me if something is wrong or missing.
Canon FD 24mm f/1.4 S.S.C. Aspherical — Bokeh & Optical Ray-Tracing Simulator
Interactive 3D portrait ray-traced through the published US3992085A optical prescription (10 elements in 8 groups, 1 aspherical) with a 17.1 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 | US3992085A · 10 elements in 8 groups (1 aspherical) | Traced surface by surface in WebGL2 |
| Entrance Pupil Diameter | 17.1 mm (at f/1.4) | Controls distant background blur disc size |
| Corner Bokeh Roundness (90% Field) | 52% at f/1.4 (≥86% from f/4) · -1.7 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) | 23.6 mm (-1.8%) | Actual framing focal length at portrait distance |
| Depth of Field (Sharp Zone) | 21 cm (90 cm – 1.11 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 Canon FD 24mm f/1.4 S.S.C. Aspherical produce?
Wide open at f/1.4, the Canon FD 24mm f/1.4 S.S.C. Aspherical has a 17.1 mm entrance pupil (24 mm ÷ 1.4) and 52% bokeh roundness in the 90% corner (-1.7 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 21 cm (90 cm to 1.11 m) with a 75° horizontal background angle of view.
Does the Canon FD 24mm f/1.4 S.S.C. Aspherical show focus breathing at portrait distance?
Based on patent US3992085A, tracing the focusing group at 0.99 m gives an effective framing focal length of 23.6 mm (-1.8% 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 Canon FD 24mm f/1.4 S.S.C. Aspherical?
The patent prescription (US3992085A) specifies 10 lens elements in 8 groups with 1 aspherical surfaces. The interactive Optical X-Ray above traces rays through every surface in real time.
Related comparisons
- Canon FD 24mm f/2.8 S.S.C.
- 24mm vs 35mm focal length comparison
- 24mm vs 50mm focal length comparison
- 28mm vs 35mm focal length comparison
- 28mm vs 50mm focal length comparison
- 23mm APS-C vs 35mm full frame focal length comparison
Compare with similar portrait lenses
- Sony FE 24mm F1.4 GM
- Canon RF 24mm F1.4 L VCM
- Nikon 24mm f/1.4G FX
- Canon RF 24mm F1.8 MACRO IS STM
- Nikon NIKKOR Z 24mm f/1.8 S
- Canon 35mm f/2 IS
Also see: depth of field, bokeh, crop factor, lens compression.