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.
Crop Factor Calculator for Equivalent Focal Length and Aperture
Inputs
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.
Exposure stays the same; equivalent aperture compares depth of field and background blur.
Results
Source crop factor
Target crop factor
Full-frame equivalent
Matching target lens
Equivalent aperture
Field of view
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Crop Factor Formulas
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))
How to use this crop factor calculator
- Pick your current format. Presets cover full frame, medium format, APS-H, Super 35, APS-C, Micro Four Thirds, 1-inch, compact, action camera, and phone-style sensors.
- Enter the lens focal length. We compute its 35mm equivalent so you can compare across systems.
- Add aperture if depth of field matters. The equivalent aperture row compares blur and DoF, while exposure remains based on the actual f-number.
- Select a target format. See what focal length matches your framing on that body.
- Use custom mode for unusual cameras. Enter sensor width and height, or enter a known crop factor for drones, phones, webcams, cinema crops, and adapters.
How Crop Factor Works
Field of view
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.
Aperture and depth of field
For depth-of-field comparison, multiply the f-number by crop factor. Exposure does not change, but blur comparison does.
Exposure and ISO
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.
Video crop modes
4K, high-frame-rate, stabilization, or open-gate modes may use different sensor areas. Multiply the normal format crop by the extra video crop.
Speed boosters
Focal reducers lower effective crop factor by compressing the image circle. A 0.71x reducer on a 2.0x body behaves near 1.42x.
Crop Factor Reference Table
| 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 |
Equivalent Focal Length Chart
| 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 FAQ
What is crop factor?
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.
How do I calculate equivalent focal length?
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.
Does crop factor make my lens longer?
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.
Does crop factor affect aperture or ISO?
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.
Is Canon APS-C different from Sony or Nikon APS-C?
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.
What is crop factor in 4K video?
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.
Can I use full-frame lenses on crop bodies?
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.
Do speed boosters change crop factor?
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.