Boneyard Tools

Crop Factor Calculator

Enter your sensor width and height to get the crop factor versus full frame, plus the 35mm-equivalent focal length and depth-of-field-equivalent f-number.

How to use the crop factor calculator

  1. Enter your sensor width and height in millimetres.
  2. Optionally enter a lens focal length and aperture.
  3. Read the crop factor and the full-frame-equivalent focal length and f-number.

Examples

APS-C with a 50mm f/1.8

sensor 23.5 x 15.6 mm, 50 mm, f/1.8
crop 1.53x, 76.7 mm equiv, f/2.8 equiv

Full frame baseline

sensor 36 x 24 mm, 50 mm
crop 1.00x, 50 mm equivalent

Frequently asked questions

What is crop factor?

Crop factor is the ratio of a 35mm full-frame sensor diagonal to your sensor diagonal. It tells you how much a smaller sensor narrows the field of view.

How do I get the 35mm-equivalent focal length?

Multiply the lens focal length by the crop factor. A 50 mm lens on a 1.5x APS-C body frames like a 75 mm lens on full frame.

What is the equivalent f-number for?

Multiplying the f-number by the crop factor gives the full-frame aperture that yields the same depth of field and similar background blur, useful when comparing systems.

Does crop factor change exposure?

No. The f-number that sets exposure stays the same. The equivalent f-number only describes depth of field and total light gathered, not the metered exposure.

What are common crop factors?

About 1.5x for most APS-C sensors, 1.6x for Canon APS-C, 2.0x for Micro Four Thirds and around 2.7x for 1-inch type sensors.

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