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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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. That is why the APS-C sold as "1.5×" actually gives 1.53×. 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 (1.53×) camera:

  • Equivalent = 35 × 1.53 ≈ 54 mm (close to a classic "50 mm" frame).
  • Equivalent aperture for DoF = f/1.8 × 1.53 ≈ f/2.8.

On Micro 4/3 (2×), 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. An APS-C sensor (1.53×; "1.5×" on spec sheets) 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 a Sony, Nikon or Fuji APS-C (1.53×) frames like a 54 mm on full frame.
Does crop factor change the aperture?
It does not change exposure (f/2.8 is still f/2.8 for metering), 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?
Worked out from each sensor diagonal: full frame 1×, Sony/Nikon/Fuji APS-C (23.5 × 15.6 mm) 1.53× — the marketed "1.5×" —, Canon APS-C (22.3 × 14.9 mm) 1.61× — the "1.6×" —, Micro 4/3 2×, 1″ 2.73× and medium format (43.8 × 32.9 mm) 0.79×, bigger than full frame. Super 35 has no single size: we use 24.6 × 13.8 mm (16:9, as on the Canon C300 Mark II), which gives 1.53×; it varies by model.
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.