Optics calculators
Crop factor calculator
Convert actual and 35 mm-equivalent focal lengths, compare sensor sizes, and find native lenses that cover your framing.
35 mm-format framing
29 mm equivalent
Canon EOS R50 · 18 mm · f/4.5 · 3 m
- Catalogue crop factor
- 1.6×
- Equivalent aperture for depth of field
- f/7.2
- For a 50 mm-equivalent view
- 31.25 mm actual
Exposure still uses f/4.5.
Lenses covering that focal length
Sensor diagonal ratio
36 × 24 mm reference diagonal ÷ your sensor diagonal = 1.613×. Named cameras use the catalogue’s 1.6× framing convention; manufacturer endpoint rounding remains on the lens profiles.
Sources for these settings
- Sensor dimensions: Canon source · Updated 2 Oct 2026
- Focal range: Canon USA source · Updated 7 Sep 2026
- Widest aperture: Canon USA source · Updated 7 Sep 2026
- Smallest aperture: Canon source · Updated 2 Oct 2026
- Minimum focus: Canon Europe source · Updated 5 Oct 2026
What these numbers mean
These are geometric estimates, not a sharpness test. The thin-lens model does not account for focus breathing, lens distortion or close-up magnification. Focus distance is entered from the camera’s sensor plane; the model approximates it as distance from the lens.
Depth of field uses a circle of confusion: a chosen acceptable blur diameter on the sensor. It is not a guarantee that a photograph will look sharp at every print size. Equivalent focal length compares framing; equivalent aperture compares depth of field at matched framing and distance, and does not change exposure.
Named zooms with variable aperture limits use their published endpoints. Intermediate limits stay unknown. Intermediate depth-of-field settings have unchecked lens limits.