Tool · Optics

Field of view & crop factor calculator

Enter a focal length and a sensor size to get the equivalent focal length and the angle of view.

Equivalent: 250mm
Crop factor: 1×
Horizontal: 8.2°
Vertical: 5.5°
Diagonal: 9.9°

Full frame · 250mm eq.

Full frame at 250mm Scene = 14mm on full frame, drawn to scale

Method

How the calculator works

Angle of view = 2 × arctan(sensor dimension / (2 × focal length)). We use the real sensor width, height and diagonal for the chosen format, so the horizontal, vertical and diagonal angles are each calculated from their own dimension.

Crop factor is the full-frame diagonal (43.3mm) divided by the sensor diagonal. Multiply a lens's focal length by it to get the full-frame equivalent field of view: a 250mm lens on Full frame frames like a 250mm lens on full frame. Depth of field and light gathering do not scale the same way, only the framing does.

Common presets: full frame 1x, APS-C Nikon, Sony and Fuji 1.5x, APS-C Canon 1.6x, Micro Four Thirds 2x and medium format (44x33) about 0.79x.