Work out focal length equivalent instantly with clear inputs, formula shown and shareable results.
Equivalent focal length is the actual focal length times the crop factor, and equivalent aperture multiplies the f-number by the same factor when comparing depth of field. Crop factor changes framing and depth of field but not exposure, which is why a 35 mm f/1.8 on APS-C frames like 52 mm and blurs like f/2.7 while still metering as f/1.8.
Equivalent focal length
equivalent = actual focal length x crop factor
Equivalent aperture
equivalent f-number = actual f-number x crop factor
equivalent = actual focal length x crop factor. Equivalent focal length is the actual focal length times the crop factor, and equivalent aperture multiplies the f-number by the same factor when comparing depth of field.
Crop factor changes framing and depth of field but not exposure, which is why a 35 mm f/1.8 on APS-C frames like 52 mm and blurs like f/2.7 while still metering as f/1.8.
Enter actual focal length, crop factor, aperture. The defaults shown are a realistic worked example — swap in your own figures to get a result you can use.