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.
Canon 135mm f/2 L — Bokeh & Optical Ray-Tracing Simulator
Interactive 3D portrait ray-traced through the published JP2018-049102A optical prescription (10 elements in 8 groups) with a 67.5 mm entrance pupil and 0.9 m minimum focus.
Optical & Portrait Specifications (Upper Body Framing)
| Optical & Portrait Metric | Measured / Patent Value | What It Means in Practice |
|---|---|---|
| Patent Prescription | JP2018-049102A · 10 elements in 8 groups | Traced surface by surface in WebGL2 |
| Entrance Pupil Diameter | 67.5 mm (at f/2) | Controls distant background blur disc size |
| Corner Bokeh Roundness (90% Field) | 89% at f/2 · -0.2 EV | Mechanical vignetting (cat’s-eye vs. round corner highlights) |
| Background Field of View (Compression) | 15° horizontal | Width of the background room visible behind the subject |
| Upper-Body Working Distance | 5.40 m | Camera-to-subject distance for head-to-waist framing |
| Effective Focal Length (Breathing) | 138.8 mm (+2.8%) | 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 | 0.9 m | Closest focusing distance from the sensor |
Questions
How much background blur and corner cat's-eye does the Canon 135mm f/2 L produce?
Wide open at f/2, the Canon 135mm f/2 L has a 67.5 mm entrance pupil (135 mm ÷ 2) and 89% bokeh roundness in the 90% corner (-0.2 EV corner falloff). 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) with a 15° horizontal background angle of view.
Does the Canon 135mm f/2 L show focus breathing at portrait distance?
Based on patent JP2018-049102A, tracing the focusing group at 5.40 m gives an effective framing focal length of 138.8 mm (+2.8% vs. the nominal 135 mm). You can toggle "Match subject size" in the simulator to see the framing shift live.
What optical design is inside the Canon 135mm f/2 L?
The patent prescription (JP2018-049102A) specifies 10 lens elements in 8 groups. The interactive Optical X-Ray above traces rays through every surface in real time.
Related comparisons
- Canon 135mm f/2 L vs. Canon RF 135mm F1.8 L IS USM
- 35mm vs 135mm focal length comparison
- 50mm vs 135mm focal length comparison
- 70mm vs 135mm focal length comparison
- 85mm vs 135mm focal length comparison
- 105mm vs 135mm focal length comparison
Compare with similar portrait lenses
- Nikon NIKKOR 135mm f/2 AI-s
- Nikon AF DC 135mm f/2D
- Sony FE 135mm F1.8 GM
- Canon RF 135mm F1.8 L IS USM
- Nikon NIKKOR Z 135mm f/1.8 S Plena
- Nikon NIKKOR 180mm f/2.8 AI
Also see: depth of field, bokeh, crop factor, lens compression.