Crop Factor Calculator
Convert a lens focal length to its full-frame equivalent using your sensor's crop factor.
Equivalent focal length75.0mm
Equivalent focal length = focal length × crop factor. The crop factor is the ratio of a full-frame sensor's diagonal to your sensor's diagonal, so a smaller sensor 'crops in' and a lens behaves like a longer one. A 50 mm lens on a 1.5× APS-C body frames like a 50 × 1.5 = 75 mm lens on full frame. Note this changes the field of view only — the actual focal length, and therefore the depth of field at a given aperture, is unchanged.
Questions
What is the equivalent focal length of 50 mm on APS-C?
Multiply by the crop factor. On a 1.5× APS-C sensor a 50 mm lens has the field of view of a 75 mm lens on full frame; on Canon's 1.6× APS-C it is 80 mm.
Does the crop factor change my depth of field?
Not directly. The crop factor only changes the field of view by cropping the image circle. The true focal length and aperture are unchanged, so depth of field at the same settings stays the same — though you often stand farther back to reframe, which deepens it.