Equivalent focal length calculator
Enter a focal length and the camera's sensor format. The result is the focal length that gives the same field of view on full frame.
What equivalence means
A lens always has the same focal length. A smaller sensor records only the centre of the image the lens projects, so the picture looks as if it were taken with a longer lens on full frame. The equivalent focal length is that longer lens: focal length × crop factor.
Equivalence describes field of view only. Perspective depends on where you stand, not on the sensor, and the f-number of the lens does not change when you mount it on a different body.
Why 35 mm on APS-C is not exactly 52.5 mm
The popular rule multiplies by 1.5. Computed from the sensor diagonal, Sony, Nikon and Fujifilm APS-C has a crop factor of 1.53×, so 35 mm frames like 53.4 mm. The difference is small, but it adds up at telephoto lengths, and Canon APS-C (1.61×) differs more.
Crop factorfull-frame diagonal ÷ sensor diagonal
Equivalent focal lengthfocal length × crop factor
Field of view2 × atan(sensor dimension ÷ (2 × focal length))
Equivalent focal lengths for common lenses
Full-frame equivalent in millimetres for every format Seroix covers.
| Format | 14 mm | 24 mm | 35 mm | 50 mm | 85 mm | 135 mm | 200 mm |
|---|---|---|---|---|---|---|---|
| Medium Format 44×33 0.79× | 11.1 | 19.0 | 27.6 | 39.5 | 67.1 | 106.6 | 158.0 |
| Full Frame 1.00× | 14.0 | 24.0 | 35.0 | 50.0 | 85.0 | 135.0 | 200.0 |
| APS-H 1.29× | 18.1 | 31.0 | 45.2 | 64.5 | 109.7 | 174.2 | 258.1 |
| APS-C (Sony, Nikon, Fujifilm) 1.53× | 21.4 | 36.6 | 53.4 | 76.3 | 129.7 | 206.1 | 305.3 |
| APS-C (Canon) 1.61× | 22.6 | 38.7 | 56.5 | 80.7 | 137.1 | 217.8 | 322.6 |
| Micro Four Thirds 2.00× | 28.0 | 48.0 | 70.0 | 100.0 | 169.9 | 269.9 | 399.9 |
| 1-inch 2.73× | 38.2 | 65.5 | 95.5 | 136.4 | 231.8 | 368.2 | 545.5 |
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