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Crop Factor Calculator
Convert a lens focal length to its full-frame equivalent.
Full-frame equivalent
—
Effective focal length.
| Crop factor | — |
|---|---|
| Actual focal | — |
| Field of view | — |
| — |
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Enter your figures above to see the step-by-step working.
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How the Crop Factor Calculator Works
Smaller camera sensors “crop” the image a lens projects, making a lens act like a longer one. Multiply the lens’s actual focal length by the sensor’s crop factor to get the full-frame equivalent. On an APS-C body (1.5×), a 50mm lens frames like a 75mm lens on full frame.
This lets you compare lenses across camera systems on equal terms. The crop factor is the ratio of the full-frame sensor’s diagonal to your sensor’s diagonal.
equivalent focal length = focal length × crop factor
Frequently Asked Questions
What is crop factor?
How much smaller a sensor is than full frame, expressed as a multiplier. APS-C is about 1.5×, Micro Four Thirds 2×.
What is a 50mm lens on APS-C?
It frames like a 75mm lens on full frame (50 × 1.5).
Does crop factor change the actual focal length?
No — the lens is still 50mm. Crop factor only tells you the equivalent field of view on full frame.
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