Crop Factor Calculator

The crop factor calculator converts a camera sensor and lens combination into 35mm full-frame equivalents. It helps photographers, filmmakers, drone pilots, and camera reviewers compare real focal length, framing, angle of view, field of view at distance, and aperture equivalence across APS-C, Micro Four Thirds, 1-inch, Super 35, full frame, and medium format systems.

What the Results Mean

Crop factor is based on sensor diagonal. A 35mm full-frame sensor is about 36 mm × 24 mm, with a diagonal of about 43.27 mm. The formula is: crop factor = 43.27 ÷ your sensor diagonal. Equivalent focal length is then actual focal length × crop factor.

Equivalent Aperture vs Exposure Aperture

The f-number on the lens still controls exposure. A 35 mm f/1.8 lens remains f/1.8 for metering and shutter speed. Equivalent aperture is different: it describes depth of field and total-light comparison at the same framing. On a 1.5× sensor, f/1.8 has a full-frame depth-of-field equivalent of about f/2.7.

How to Use This Calculator

1. Select a sensor preset or choose custom and enter the sensor width and height in millimeters.
2. Enter the lens focal length printed on the lens. Add the aperture if you want equivalent aperture results.
3. Enter a subject distance to estimate how wide and tall the captured scene will be at that distance.
4. Use portrait orientation if the camera is rotated vertically, because horizontal and vertical field of view swap.

Why Angle of View Is Included

Equivalent focal length is a convenient shorthand, but angle of view is the actual geometric result. This calculator shows horizontal, vertical, and diagonal angles because two sensors with the same diagonal crop factor can still differ slightly when their aspect ratios are not the same.

FAQ

Does crop factor make my lens longer?

No. The focal length is an optical property of the lens and does not change. Crop factor only describes how the sensor size changes framing compared with 35mm full frame.

Why is Micro Four Thirds called 2× crop?

A Micro Four Thirds sensor is about 17.3 mm × 13 mm. Its diagonal is roughly half the 35mm full-frame diagonal, so the crop factor is close to 2×.

Can a medium format camera have a crop factor below 1?

Yes. A sensor larger than 35mm full frame has a diagonal larger than 43.27 mm, so the crop factor is below 1. The same lens gives a wider angle of view than it would on full frame.

Should I use crop factor for depth of field?

Use equivalent aperture when comparing depth of field at the same framing and viewing size. Use the actual f-number for exposure settings, flash power, and light meter readings.