Crop Factor Calculator

Pick your sensor and focal length — get the 35 mm equivalent, the crop factor and the equivalent aperture for depth of field, instantly.

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Your camera & lens

Sensor
Equivalent on (target format)
35 mm equivalent
0mm
0crop factor
0equiv. aperture (DoF)
0sensor size
0mm ø
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How crop factor is calculated

The 35 mm equivalent is the real focal length multiplied by your sensor's crop factor:

Equivalent=focal × crop factor

The crop factor is a full-frame sensor diagonal (43.3 mm) divided by your sensor's diagonal. The smaller the sensor, the larger the factor and the more "telephoto" the lens looks. The aperture for exposure does not change, but the equivalent aperture (f × factor) tells you how the depth of field compares with full frame.

Example: a 35 mm equivalent on APS-C

A 35 mm f/1.8 on an APS-C (1.5×) camera:

  • Equivalent = 35 × 1.5 = 52.5 mm (a classic "50 mm" frame).
  • Equivalent aperture for DoF = f/1.8 × 1.5 ≈ f/2.7.

On Micro 4/3 (2.0×), that same 35 mm would frame like a 70 mm.

Crop factor FAQ

What is crop factor?
It is the ratio between a full-frame (35 mm) sensor diagonal and your camera's sensor diagonal. A 1.5× APS-C sensor is smaller, so it "crops" the image and a lens looks more telephoto than its focal length suggests.
How do I work out the 35 mm equivalent?
Multiply the real focal length by the crop factor. A 35 mm on APS-C (1.5×) frames like a 52.5 mm on full frame.
Does crop factor change the aperture?
It does not change the light gathered (f/2.8 is still f/2.8 for exposure), but it does change the equivalent depth of field: multiply the f-number by the crop factor to compare blur with full frame.
What crop factors are there?
Common ones: full frame 1.0×, APS-C 1.5× (Sony/Nikon/Fuji) or 1.6× (Canon), Micro 4/3 2.0×, 1″ ≈ 2.7× and medium format ≈ 0.79× (bigger than full frame).
Do I lose quality with a smaller sensor?
Not directly from the crop; it depends more on sensor technology. What does change is the field of view, the depth of field at the same aperture and low-light performance.