Crop Factor Calculator
This crop factor calculator shows how your sensor compares with full frame: choose sensor and lens, read the crop factor and see the full-frame focal length, the equivalent aperture and the ISO value.
Example: Sensor format: APS-C 23.5 × 15.6 mm · Lens focal length 35 mm · Aperture 1.8 · ISO value 100 → Crop factor and full-frame equivalent: Crop factor 1.53: 35 mm equals 54 mm on full frame. Source: Wikipedia – Crop factor (diagonal of 36 × 24 mm = 43.27 mm divided by the sensor diagonal). Updated: .
How it is calculated
A 35 mm lens on an APS-C sensor of 23.5 × 15.6 mm has a crop factor of 1.53 and shows the same angle of view as a 54 mm lens on full frame. The calculator works out the crop factor and equivalents from the sensor dimensions.
How it is calculated
The crop factor is the diagonal of the full-frame format (36 × 24 mm, 43.27 mm) divided by the diagonal of your sensor. It converts focal length: focal length times crop factor gives the full-frame equivalent focal length. The equivalent aperture, a measure of depth of field and total light, scales the same way, and the equivalent ISO value with the square of the factor. The table shows the reverse, which real focal length you need for typical full-frame focal lengths.
What to keep in mind
- The focal length itself does not change, only the framing: a 35 mm lens remains a 35 mm lens.
- The aperture still works as printed for exposure; the equivalent aperture only describes depth of field in comparison.
- Sensor sizes differ slightly between makers. For custom dimensions enter width and height in millimeters.
Related photo tools: the depth of field calculator, the print size calculator and the ND filter calculator.
Frequently asked questions
How do I calculate the crop factor?
Divide the diagonal of full frame (43.27 mm) by the diagonal of your sensor. For 23.5 × 15.6 mm that is about 1.53.
What does full-frame equivalent focal length mean?
The focal length that gives the same angle of view on full frame. A 35 mm lens at crop 1.53 equals about 54 mm.
Does the crop factor change the exposure?
No, the real aperture counts for exposure. The equivalent aperture only compares depth of field and total light with full frame.
What is the crop factor of Micro Four Thirds?
About 2.0, because the sensor diagonal is roughly half as long as on full frame.
Sources and legal basis
- Wikipedia – Crop factor (diagonal of 36 × 24 mm = 43.27 mm divided by the sensor diagonal)
- Wikipedia – Image sensor format (Sensorgrößen in mm)
As of: · Editorial policy
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