Formulas
- Equivalent focal length = focal length × crop factor
- Equivalent aperture (for depth of field) = f-number × crop factor
- Angle of view = 2 × arctan(sensor size ÷ (2 × focal length))
Example
A 35 mm f/1.8 lens on an APS-C camera (1.5×) frames like a 52.5 mm lens on full frame, with background blur like f/2.7. The horizontal angle of view is 37.8°.
What does not change
Exposure stays at f/1.8: the same shutter speed and ISO give the same brightness. The crop factor changes the framing and the depth of field, not the light per area of the sensor.
Phone cameras have crop factors of 3 to 7. Use the “other crop factor” field and the real focal length from the photo details.
Then see how much will be sharp with the depth of field calculator.
Frequently asked questions
Is a 50 mm lens on APS-C a 75 mm lens?
It frames like 75 mm on full frame, but it is still a 50 mm lens: perspective depends on where you stand, not on the lens.
Which crop factor does my camera have?
Nikon, Sony and Fujifilm APS-C: 1.5×; Canon APS-C: 1.6×; Micro Four Thirds (Olympus/OM System, Panasonic): 2×; 1-inch compacts: 2.7×.
See also
Results are estimates for information only and are not financial, legal or medical advice. Rates, taxes and fees vary — confirm with a professional or your lender.