Free calculator
Field of View Calculator
A 50mm lens on a 36 × 24 mm full-frame sensor sees 39.6° across and 27.0° top to bottom; at 10 ft the frame is 7.20 ft wide and 4.80 ft tall. Enter a lens, the recorded area of your sensor and a distance, with an anamorphic squeeze if you use one.
Free, no sign-up. Runs in your browser.
This web tool includes the anamorphic squeeze in the diagonal angle as well as the horizontal one. Save, share and get the Pro tools in the app.
How it works
angle = 2 × atan(sensor dimension ÷ (2 × focal length))Use the sensor width for the horizontal angle, the height for the vertical and the diagonal for the diagonal angle. Use the area your recording mode actually uses: a 16:9 or cropped mode sees less than the full sensor.
Where
- sensor dimension
- width, height or diagonal of the recorded area(mm)
- focal length
- as marked on the lens(mm)
frame width = distance × sensor width ÷ focal lengthThe same as 2 × distance × tan(angle ÷ 2). Distance is from the focal plane. The frame height uses the sensor height.
horizontal angle = 2 × atan(sensor width × squeeze ÷ (2 × focal length))An anamorphic lens squeezes a wider view onto the same sensor width. The vertical angle and frame height are those of the sensor as it is; the diagonal uses the desqueezed width.
How this compares with the CineMath app
The horizontal and vertical angles and the frame sizes match the app. With an anamorphic squeeze on, the app works the diagonal angle from the sensor as entered, so a 2× lens on Super 35 at 50mm shows a 34.6° diagonal beside a 52.9° horizontal angle. This page uses the desqueezed width for the diagonal too: 56.0°.
Worked example
25mm on Super 35 (24.89 × 18.66 mm), subject at 10 ft
- horizontal = 2 × atan(24.89 ÷ 50) = 52.9°
- vertical = 2 × atan(18.66 ÷ 50) = 40.9°
- frame width = 3,048 mm × 24.89 ÷ 25 = 3,035 mm = 9.96 ft
- frame height = 3,048 mm × 18.66 ÷ 25 = 2,275 mm = 7.46 ft
A 25mm on Super 35 sees 52.9° × 40.9°, a frame about 10 ft by 7½ ft at 10 ft.
Quick reference
Horizontal angle and frame width at 10 ft
| Lens | Full frame (36 mm) | Super 35 (24.89 mm) | Micro Four Thirds (17.3 mm) |
|---|---|---|---|
| 18 mm | 90.0° · 20.0 ft | 69.3° · 13.8 ft | 51.3° · 9.61 ft |
| 25 mm | 71.5° · 14.4 ft | 52.9° · 9.96 ft | 38.2° · 6.92 ft |
| 35 mm | 54.4° · 10.3 ft | 39.1° · 7.11 ft | 27.8° · 4.94 ft |
| 50 mm | 39.6° · 7.20 ft | 28.0° · 4.98 ft | 19.6° · 3.46 ft |
| 85 mm | 23.9° · 4.24 ft | 16.7° · 2.93 ft | 11.6° · 2.04 ft |
| 135 mm | 15.2° · 2.67 ft | 10.5° · 1.84 ft | 7.3° · 1.28 ft |
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 field of view?
Angle of view = 2 × atan(sensor width ÷ (2 × focal length)). A 35mm lens on full frame (36 mm wide) sees 54.4° across; on Super 35 (24.89 mm wide) the same lens sees 39.1°. Use the height and the diagonal the same way for the vertical and diagonal angles.
How wide is the frame at a given distance?
Distance × sensor width ÷ focal length. A 50mm on full frame at 10 ft covers 10 × 36 ÷ 50 = 7.2 ft across. It is a straight proportion, so twice the distance gives twice the width.
What lens do I need for a given frame width?
Turn the formula round: focal length = sensor width × distance ÷ frame width. To fit 12 ft across from 20 ft away on Super 35, you need 24.89 × 20 ÷ 12 = 41.5 mm, so a 40mm gives a little room.
How does an anamorphic lens change the field of view?
It multiplies the width the lens sees by the squeeze. A 40mm 2× anamorphic on Super 35 sees 63.8° across, against 34.6° for a 40mm spherical lens; vertically it sees the same as the spherical lens. At 10 ft its frame is 12.4 ft wide.
Does the field of view change when I focus closer?
A little. The focal length on the barrel is exact at infinity focus; focused close, most lenses see a slightly different angle, which is focus breathing. The calculator uses the marked focal length, so close-up frame sizes are approximate.