Tool
Focal Length Equivalence
Understand what a lens's field of view looks like on different sensor sizes.
Result
50mm on APS-C is equivalent to
75mm
on Full frame
Crop factor: APS-C = 1.5× · Full frame = 1×
Why sensor size matters
A lens's focal length is a physical property, but the field of view you actually see depends on sensor size. A 35mm lens on an APS-C body frames like a ~52mm lens on full frame.
Crop factors
Full frame has a 1.0× crop factor, APS-C is typically 1.5×, and Micro Four Thirds is 2.0×. Multiply the focal length by the crop factor to get the full-frame equivalent field of view.