Free calculator
Anamorphic Calculator
A 2× anamorphic lens on the Super 35 film gate (24.89 × 18.66 mm) desqueezes a 4:3 frame to 2.67:1, and a 50 mm lens on it frames the width like a 25 mm spherical lens. Enter any squeeze, sensor and focal length to check where a lens and recording mode land before the camera test.
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The CineMath app currently names the first common ratio within 0.05, so 2.39 and 2.40 read 2.35:1 there; this tool names the nearest ratio within 0.01, so they read 2.39:1 and 2.40:1, and it keeps each field to a realistic range. Save, share and get the Pro tools in the app.
How it works
desqueezed aspect = (sensor width ÷ sensor height) × squeezeAn anamorphic lens squeezes the picture sideways by its squeeze factor; desqueezing in post stretches the width back out. The height does not change, so the recorded ratio is multiplied by the squeeze.
Where
- width, height
- the sensor area you record(mm)
- squeeze
- the lens squeeze factor: 2 for a 2× lens, 1 for spherical
desqueezed width = sensor width × squeezeThe width of the picture once it is stretched back out: 24.89 mm with a 2× lens is 49.78 mm wide.
H-equivalent = focal length ÷ squeezeSqueezing twice the width onto the sensor gives a horizontal angle of view like a lens of half the focal length. Vertically, the lens still frames like its marked focal length, so a 50 mm 2× anamorphic is as wide as a 25 mm spherical lens and as tall as a 50 mm one.
name = the common ratio nearest the result, if it is within 0.01The named ratios are 4:3, 3:2, 16:9, 1.85:1, 2:1, 2.35:1, 2.39:1, 2.40:1, 2.66:1 and 2.76:1. A result further than 0.01 from all of them is shown as its own value, such as 2.36:1. The exact desqueezed ratio is always shown in brackets: 2× on 4:3 is named 2.66:1, its usual name, and is 2.67:1 exactly.
Custom squeezes and sensors
The squeeze field takes any factor, such as 1.65 or 1.3, and is read to four decimals (1.23456 is used as 1.2346). Pick a sensor from the list or type the width and height of the area you record: a recording mode usually uses less of the sensor than its full size, and the maker's spec sheet gives its dimensions in millimeters. For the same calculation in pixels, with letterbox bars and a delivery frame, use the aspect ratio calculator.
Worked example
A 2× 50 mm lens on the Super 35 film gate
- Recorded: 24.89 ÷ 18.66 = 1.334, named 4:3
- Desqueezed: 1.334 × 2 = 2.67:1, named 2.66:1
- Desqueezed width: 24.89 mm × 2 = 49.78 mm
- Horizontal equivalent: 50 mm ÷ 2 = 25 mm
4:3 → 2.66:1 (2.67:1), 49.78 mm wide, and the 50 mm frames the width like a 25 mm spherical lens
Quick reference
Desqueezed aspect ratio by sensor and squeeze (exact, to two decimals)
| Sensor | 1.25× | 1.33× | 1.5× | 1.8× | 2.0× |
|---|---|---|---|---|---|
| Full frame (36 × 24 mm) | 1.88:1 | 2.00:1 | 2.25:1 | 2.70:1 | 3.00:1 |
| Super 35 film gate (24.89 × 18.66 mm) | 1.67:1 | 1.77:1 | 2.00:1 | 2.40:1 | 2.67:1 |
| Super 35 16:9 (23.76 × 13.37 mm) | 2.22:1 | 2.36:1 | 2.67:1 | 3.20:1 | 3.55:1 |
| APS-C (22.3 × 14.9 mm) | 1.87:1 | 1.99:1 | 2.24:1 | 2.69:1 | 2.99:1 |
| Four Thirds (17.3 × 13 mm) | 1.66:1 | 1.77:1 | 2.00:1 | 2.40:1 | 2.66:1 |
Horizontal-equivalent spherical focal length by squeeze
| Lens | 1.25× | 1.33× | 1.5× | 1.8× | 2.0× |
|---|---|---|---|---|---|
| 24 mm | 19 mm | 18 mm | 16 mm | 13 mm | 12 mm |
| 32 mm | 26 mm | 24 mm | 21 mm | 18 mm | 16 mm |
| 40 mm | 32 mm | 30 mm | 27 mm | 22 mm | 20 mm |
| 50 mm | 40 mm | 38 mm | 33 mm | 28 mm | 25 mm |
| 75 mm | 60 mm | 56 mm | 50 mm | 42 mm | 38 mm |
| 100 mm | 80 mm | 75 mm | 67 mm | 56 mm | 50 mm |
| 135 mm | 108 mm | 102 mm | 90 mm | 75 mm | 68 mm |
Save, share and get the Pro tools in the CineMath app
CineMath is a free download for iPhone, iPad and Mac, with this calculator built in. In version 1.3, coming soon to the App Store, CineMath Professional saves calculations to your history, shares them as links, and adds the Camera Database and Data Planning.
Questions
How do I calculate the desqueezed aspect ratio?
Divide the sensor width by its height and multiply by the squeeze. The Super 35 film gate is 24.89 × 18.66 mm, a 1.334 ratio; with a 2× lens that is 2.67:1. Full frame (36 × 24 mm) with a 1.5× lens is 1.5 × 1.5 = 2.25:1.
What focal length is a 50 mm anamorphic lens in spherical terms?
Horizontally, divide by the squeeze: a 50 mm 2× lens is as wide as a 25 mm spherical lens, and a 50 mm 1.33× lens is as wide as a 38 mm one (50 ÷ 1.33 = 37.6). Vertically it still frames like a 50 mm, which is why anamorphic close-ups look different from the spherical lens with the same width.
Why does 2× on a 4:3 sensor give 2.67:1 and not 2.39:1?
4:3 × 2 = 2.67. A 2.39:1 picture is extracted from that frame by cropping the sides. To land near 2.39:1 without cropping, the recorded frame must be about 1.2:1 for a 2× lens: ARRI's ALEXA 35 6:5 mode (20.22 × 16.95 mm) gives 2.39:1, and 1.8× on 4:3 gives 2.40:1.
What squeeze suits a 16:9 sensor?
A 1.33× lens: 16:9 × 1.33 = 2.36:1, close to scope with a small crop at the sides. A 2× lens on 16:9 gives about 3.56:1, which needs a large crop to reach 2.39:1.
Why is a desqueezed 2.40 named 2.40:1 rather than 2.39:1?
The tool names the common ratio nearest the result, and 2.40:1 is one of the names in its list, next to 2.35:1 and 2.39:1. The DCI scope frame, 4096 × 1716, is 2.39:1. The names are only 0.01 apart, so check the exact value in brackets against a delivery spec.