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Camera Crop Factor Converter: Equivalent Focal Length

The same lens produces a different field of view depending on the sensor behind it, and crop factor is the number that lets you compare them directly.

Crop factor compares a sensor to full frame

Crop factor is the ratio between a full-frame sensor's diagonal and a given sensor's diagonal. Full frame is the baseline at 1.0x; smaller sensors have a crop factor above 1.0x, meaning they capture a narrower field of view from the same lens.

Equivalent focal length = actual focal length Γ— crop factor

A 50 mm lens on a 1.5x crop sensor gives a field of view equivalent to 50 Γ— 1.5 = 75 mm on full frame β€” the lens itself is still physically 50 mm, but it frames a tighter shot than 50 mm would on full frame.

Common sensor crop factors

Full frame: 1.0x. Canon APS-C: 1.6x. Nikon/Sony/Fujifilm APS-C: 1.5x. Micro Four Thirds (Olympus/Panasonic): 2.0x. 1-inch sensor (many compacts): 2.7x.

Canon APS-C uses a slightly different crop factor than other brands

Canon's APS-C sensors are physically a bit smaller than the APS-C sensors used by Nikon, Sony, and Fujifilm, which is why Canon uses 1.6x while the others use 1.5x, even though all are commonly grouped under the same 'APS-C' label.

Crop factor changes framing, not the lens's actual aperture

A 50mm f/1.8 lens is still physically f/1.8 on any sensor β€” crop factor affects the equivalent field of view and, by some conventions, equivalent depth of field, but the lens's actual light-gathering aperture and true focal length do not change.

Why the same lens feels "longer" on a smaller sensor

A smaller sensor doesn't zoom the image in β€” it simply captures a smaller crop out of the same projected image circle a lens produces, which happens to look similar to a longer focal length's framing on a full-frame sensor. This is why photographers describe crop-sensor lenses using 'full-frame equivalent' focal lengths for easy comparison.

Crop factor matters most when comparing gear across formats

If you're used to shooting full frame and switching to (or comparing against) a Micro Four Thirds or APS-C system, crop factor tells you what focal length to actually look for to get a familiar field of view, which is especially useful when choosing lenses for wildlife, portrait, or wide-angle work across different camera systems.

Frequently Asked Questions

Does crop factor make a lens physically zoom in more?

No β€” the lens's actual focal length and optical properties don't change. Crop factor describes how much of the lens's projected image the sensor actually captures, which produces a field of view equivalent to a longer focal length, not actual added magnification.

Do smartphone cameras have a crop factor too?

Yes, typically a very high one, since phone sensors are much smaller than even a 1-inch sensor. This is part of why phone camera specs are usually given directly as a 'full-frame equivalent' focal length (like 24mm or 77mm) rather than the tiny actual focal length of the physical lens.