Focal Length Calculator
Enter a lens's actual focal length and select your sensor's crop factor to find the full-frame equivalent focal length.
How crop factor affects focal length
A camera sensor smaller than a full-frame (35mm) sensor captures a narrower field of view with the same lens, making the image look like it was taken with a longer lens. The equivalent focal length is found by multiplying the lens's actual focal length by the sensor's crop factor.
This matters for comparing lenses across different camera systems — a 50mm lens on an APS-C camera (1.5x crop) frames a scene similarly to a 75mm lens on a full-frame camera, even though the lens itself is still physically a 50mm lens.
Frequently asked questions
Does crop factor change the lens's actual focal length?
No — the lens's physical focal length and aperture don't change. Crop factor only affects the field of view captured by a smaller sensor, which makes the image appear more zoomed-in compared to the same lens on a full-frame sensor.
What crop factor does my camera have?
Full-frame (35mm) sensors have a 1.0x crop factor. Most APS-C cameras are around 1.5x (1.6x for Canon specifically), and Micro Four Thirds cameras have a 2.0x crop factor — check your camera's specifications if you're unsure.
Does crop factor also affect depth of field?
Indirectly — while the lens's physical aperture doesn't change, achieving the same field of view on a smaller sensor typically requires a different shooting distance or focal length, which affects the resulting depth of field in the final image.