Crop Factor & Equivalent Focal Length Calculator
Calculate the crop factor of a camera sensor and find the equivalent focal length relative to a full-frame (35mm) sensor.
Common values: Full-frame = 1.0, APS-C Nikon/Sony = 1.5, APS-C Canon = 1.6, Micro 4/3 = 2.0
Formulas Used
Crop Factor from sensor dimensions:
Crop Factor = FF_diagonal / Sensor_diagonal
where FF_diagonal = √(36² + 24²) ≈ 43.267 mm (35mm full-frame standard)
and Sensor_diagonal = √(width² + height²)
Equivalent Focal Length:
EFL = Native_FL × Crop_Factor
Native Focal Length from Equivalent:
Native_FL = EFL / Crop_Factor
Diagonal Angle of View:
AoV = 2 × arctan(FF_diagonal / (2 × EFL))
Assumptions & References
- Reference: Ray, S.F. (2002). Applied Photographic Optics. Focal Press.