What is 35mm equivalent?
35mm equivalent is a way to compare lenses across cameras with different sensor sizes. Because smaller sensors capture a smaller portion of the lens's image circle, lenses appear "longer" on smaller sensors. A 50mm lens frames a normal field of view on a full-frame camera but acts like a 75mm short telephoto on a 1.5× APS-C body.
Common crop factors
- Full frame (35mm) — 1.0× (Sony A7, Nikon Z6, Canon R6, Leica Q).
- APS-C (Nikon, Sony, Pentax, Fuji) — 1.5×.
- APS-C (Canon) — 1.6× (slightly smaller sensor).
- Micro Four Thirds — 2.0× (Olympus / OM, Panasonic).
- 1-inch — 2.7× (Sony RX100, premium compacts).
- Smartphone main camera — typically 5–7× depending on sensor.
Why depth of field also changes
Crop factor only changes the angle of view; it does not change the lens's actualfocal length. To match the depth of field as well, you also need to multiply the f-number by the same factor — a 50mm f/1.8 lens on APS-C frames like 75mm and gives roughly the depth of field of a 75mm f/2.7 lens on full frame.
FAQ
Does this affect exposure? No. Exposure depends on aperture, shutter, and ISO; not on sensor size.
What about phones with multiple lenses? The phone usually reports the equivalent focal length already (e.g. "0.5×, 1×, 3×" maps to roughly 13mm, 26mm, 77mm equivalent).