Crop factor is calculated from the custom sensor diagonal.
Field of view uses a proportional 3:2 sensor estimate when only crop factor is entered.
crop factor = 43.27 / sensor diagonal35mm equivalent focal length = actual focal length x crop factortarget lens = source focal length x source crop factor / target crop factorequivalent aperture for depth of field = f-number x crop factorfield of view = 2 x arctangent(sensor dimension / (2 x focal length))Crop factor does not change the lens. A 50 mm lens remains 50 mm, but a smaller sensor records a narrower part of its image circle.
Equivalent focal length describes field of view. A 35 mm lens on 1.5x APS-C frames like about 52.5 mm on full frame.
For depth-of-field comparison, multiply the f-number by crop factor. Exposure does not change, but blur comparison does.
f/2.8 at ISO 400 meters as f/2.8 at ISO 400 across formats. Sensor size affects total light capture and noise comparisons, not the exposure setting.
4K, high-frame-rate, stabilization, or open-gate modes may use different sensor areas. Multiply the normal format crop by the extra video crop.
Focal reducers lower effective crop factor by compressing the image circle. A 0.71x reducer on a 2.0x body behaves near 1.42x.
| Format | Typical dimensions | Diagonal | Crop factor | Example cameras |
|---|---|---|---|---|
| Medium Format 44 x 33 | 43.8 x 32.9 mm | 54.78 mm | 0.79x | Fujifilm GFX, Hasselblad X System |
| Full Frame | 36.0 x 24.0 mm | 43.27 mm | 1.00x | Canon R, Nikon Z, Sony a7, Panasonic S |
| APS-H | 27.9 x 18.6 mm | 33.53 mm | 1.29x | Canon EOS-1D series, Leica M8 |
| Super 35 | 24.9 x 18.7 mm | 31.13 mm | 1.39x | ARRI Alexa S35, Sony FX30, Canon C70 crop modes |
| Nikon/Sony/Fujifilm APS-C | 23.6 x 15.7 mm | 28.35 mm | 1.53x | Nikon DX, Sony APS-C, Fujifilm X |
| Canon APS-C | 22.3 x 14.9 mm | 26.82 mm | 1.61x | Canon EOS R7, R10, Rebel, 90D |
| Micro Four Thirds | 17.3 x 13.0 mm | 21.64 mm | 2.00x | Panasonic GH/G, OM System, Olympus |
| 1-inch type | 13.2 x 8.8 mm | 15.86 mm | 2.73x | Sony RX100, ZV-1, DJI Air 2S |
| Phone 1/1.3-inch class | 9.6 x 7.2 mm | 12.00 mm | 3.61x | Recent large-sensor phone main cameras |
| Action / compact 1/2.3-inch | 6.17 x 4.55 mm | 7.67 mm | 5.64x | GoPro-style action cameras, compact cameras |
| Actual lens | Full Frame | APS-C 1.5x | Canon APS-C 1.6x | Micro Four Thirds | 1-inch type |
|---|---|---|---|---|---|
| 12 mm | 12 mm | 18 mm | 19 mm | 24 mm | 33 mm |
| 16 mm | 16 mm | 24 mm | 26 mm | 32 mm | 44 mm |
| 24 mm | 24 mm | 36 mm | 38 mm | 48 mm | 66 mm |
| 35 mm | 35 mm | 53 mm | 56 mm | 70 mm | 96 mm |
| 50 mm | 50 mm | 75 mm | 80 mm | 100 mm | 137 mm |
| 85 mm | 85 mm | 128 mm | 136 mm | 170 mm | 232 mm |
| 135 mm | 135 mm | 203 mm | 216 mm | 270 mm | 369 mm |
| 200 mm | 200 mm | 300 mm | 320 mm | 400 mm | 546 mm |
| 300 mm | 300 mm | 450 mm | 480 mm | 600 mm | 819 mm |
Crop factor is the ratio between the full-frame 35mm diagonal, about 43.27 mm, and the diagonal of another camera sensor. It describes how tightly a lens frames compared with full frame.
Multiply the actual focal length by the crop factor. For example, a 50 mm lens on a 1.5x APS-C camera frames like a 75 mm lens on full frame.
No. The physical focal length does not change. A smaller sensor records a narrower field of view, so the image looks like it was taken with a longer lens on full frame.
Crop factor does not change exposure. The same f-number and ISO meter the same brightness, but equivalent aperture is useful for comparing depth of field and background blur across formats.
Yes. Canon APS-C is commonly about 1.6x, while Sony, Nikon, Fujifilm, and Pentax APS-C are commonly about 1.5x. The difference is small but visible in equivalence calculations.
Some cameras use only part of the sensor for 4K or high-frame-rate video. That extra video crop multiplies the normal sensor crop factor, narrowing the field of view.
Usually yes when the mount or adapter supports it. The lens keeps its focal length and aperture, but the crop body records the center portion of the image circle.
Yes. A focal reducer or speed booster lowers the effective crop factor by compressing the image circle, widening the field of view and increasing light per area at the sensor.