Crop Factor Calculator
Convert a lens focal length and aperture to its 35mm full-frame equivalent — or work out what lens you need on a crop sensor to match a full-frame look.
What crop factor means
Crop factor compares a sensor's diagonal to a 35mm full-frame sensor. A 35mm lens on a 1.5× APS-C camera frames the scene like a 52.5mm lens on full-frame. Multiplying the f-number by the crop factor gives the aperture that produces the same depth of field on full-frame; the lens still gathers light at its marked f-number for exposure purposes.
Frequently asked questions
Does crop factor change my exposure?
No. f/2.8 meters as f/2.8 on any sensor. The “equivalent aperture” only describes depth of field and total light gathered across the frame, which affects noise at matched output size.
Why do Canon APS-C cameras use 1.6×?
Canon's APS-C sensors are slightly smaller (about 22.3×14.9 mm) than Sony, Nikon, and Fujifilm APS-C sensors (about 23.5×15.6 mm), so their diagonal ratio to full-frame works out to roughly 1.6 instead of 1.5.
Does a speed booster reverse the crop?
Partially. A 0.71× focal reducer multiplies the crop factor by 0.71, so a 1.5× APS-C body behaves like roughly 1.07× — close to full-frame framing with one extra stop of light.
Last updated: 2026-07-12