Crop Factor Calculator
Crop factor = full-frame diagonal (43.27 mm) ÷ your sensor diagonal. A Nikon or Sony APS-C sensor (23.5 × 15.6 mm) has a crop factor of 1.53, so a 35 mm f/1.8 lens frames like 54 mm on full frame and gives the depth of field of about f/2.8. Its diagonal angle of view is 43.9°.
How to use
- Choose your camera sensor and the reference sensor (full frame by default), or enter custom sizes in mm.
- Enter the real focal length and f-number of your lens.
- Read the crop factor, the equivalent focal length and aperture, and the angle of view. The frame drawing compares the two sensor sizes.
How it works
Crop factor = reference diagonal ÷ sensor diagonal, where diagonal = √(width² + height²). Full frame is 36 × 24 mm, diagonal 43.27 mm.
Equivalent focal length = focal length × crop factor (same diagonal field of view). Equivalent aperture for depth of field = f-number × crop factor.
Angle of view = 2 × atan(sensor dimension ÷ (2 × focal length)), for a rectilinear lens focused at infinity, measured across the width, height or diagonal.
FAQ
Does a crop sensor change the f-number for exposure?
No. f/2.8 gives the same exposure (shutter speed and ISO) on any sensor. The equivalent aperture only describes depth of field and total light gathered when you frame the same shot.
Why do Canon and Nikon APS-C have different crop factors?
Canon APS-C sensors are slightly smaller (about 22.3 × 14.9 mm, crop 1.6) than Nikon, Sony and Fujifilm APS-C (about 23.5 × 15.6 mm, crop 1.5). Exact sizes vary a little by model.
Why does the equivalent focal length only match the diagonal?
Sensors with a different aspect ratio, like 4:3 Micro Four Thirds against 3:2 full frame, crop differently in width and height. The crop factor is defined on the diagonal, so width or height views can differ slightly.
Is the angle of view exact?
It is the geometric value for a rectilinear lens at infinity focus. Fisheye lenses, close focusing and lens breathing change the real view.
What sensor size does a phone have?
Main phone cameras range from about 1/2.5-inch type to 1-inch type. The phone entry here uses a 1/1.3-inch type example (9.8 × 7.4 mm); check your model and use Custom for exact numbers.