Lens Focal Length & Field of View Calculator
Calculate horizontal and diagonal field of view, 35mm full-frame focal length equivalence, crop factors, and equivalent depth of field aperture across cinema and photography sensors.
1. Camera Sensor & Format
2. Visual Field of View Framing
A 50mm lens on Full Frame produces a standard 39.6° horizontal angle of view.
Understanding Sensor Crop Factor & Aperture Equivalence
When using a smaller sensor (such as Super 35 or Micro Four Thirds), the sensor only captures the central portion of the lens's projected image circle.
- Focal Length Equivalence: A 25mm lens mounted on a Micro Four Thirds camera (2.0x crop) has the exact same field of view as a 50mm lens on a Full Frame camera.
- Depth of Field Equivalence: Crop factors also multiply the depth of field equivalent aperture. A 25mm f/1.4 lens on Micro Four Thirds provides the light gathering of f/1.4 for exposure, but renders the shallow depth of field of an f/2.8 lens on Full Frame.
Worked examples: one lens on each sensor
The tool multiplies the focal length and the aperture by the crop factor to give the full-frame equivalent, and works out the field of view from the sensor's width and height with 2 times the arctangent of the dimension over twice the focal length. The table puts a 35 mm lens at f/2.8 on each of the seven sensor sizes the tool offers.
| Sensor | Crop | Equivalent focal length | Equivalent aperture | Horizontal FOV | Vertical FOV |
|---|---|---|---|---|---|
| Full frame 35mm | 1x | 35 mm | f/2.8 | 54.4° | 37.8° |
| Super 35 or APS-C | 1.5x | 53 mm | f/4.2 | 37.8° | 25.8° |
| Canon APS-C | 1.6x | 56 mm | f/4.5 | 35.3° | 24.0° |
| Micro Four Thirds | 2x | 70 mm | f/5.6 | 27.8° | 21.0° |
| Medium format | 0.79x | 28 mm | f/2.2 | 64.1° | 50.3° |
| 1-inch type | 2.7x | 95 mm | f/7.6 | 21.4° | 14.3° |
| Super 16 cinema | 3x | 105 mm | f/8.4 | 20.2° | 12.1° |
The field of view is the physical angle the sensor sees, and the equivalent focal length is the full-frame lens that would show the same angle. A 35 mm lens on Micro Four Thirds frames like a 70 mm lens on full frame. The equivalent aperture follows the same multiplier, so f/2.8 on Micro Four Thirds corresponds to f/5.6 in full-frame terms for depth of field, while the exposure the lens gives is still that of f/2.8. Medium format has a crop factor under 1, which is why it shows a wider equivalent angle for the same lens.
The second table keeps the Super 35 sensor, 24 mm by 16 mm in the tool, and changes the lens.
| Lens | Equivalent focal length | Horizontal FOV | Vertical FOV |
|---|---|---|---|
| 14 mm | 21 mm | 81.2° | 59.5° |
| 24 mm | 36 mm | 53.1° | 36.9° |
| 35 mm | 53 mm | 37.8° | 25.8° |
| 50 mm | 75 mm | 27.0° | 18.2° |
| 85 mm | 128 mm | 16.1° | 10.8° |
The equivalence describes framing and depth of field only. Lens design, perspective at a given subject distance and close-focus behaviour follow the real focal length, so a 50 mm lens on Super 35 frames like a 75 mm lens but does not behave like one in every way.
Working Vocabulary
Key camera optics and sensor terminology:
- Field of View (FOV). The observable angular extent of a scene captured by a camera sensor at a specific focal length, measured in degrees.
- Crop Factor. The ratio of the diagonal dimensions of a full-frame 35mm sensor (43.3mm) compared to a smaller or larger camera sensor.
- Super 35. The traditional motion picture film gauge and digital sensor standard (approx 24.89mm × 18.66mm).
- Equivalent Aperture. The adjusted f-stop value required on a 35mm full-frame camera to produce the identical depth of field and background blur.