PhotoPrepHow it works
For a rectilinear lens, the angle is 2 × atan(sensor dimension / (2 × focal length)). Scene dimensions use distance × sensor dimension / focal length. This approximation assumes infinity-focus focal length and excludes distortion, focus breathing, stabilization crops and fisheye projection. The comparison drawing is schematic.
Example
A 50 mm lens on a 36 × 24 mm sensor at 3 m covers approximately 2.16 × 1.44 m. Doubling focal length halves the estimated scene dimensions at the same distance. Sensor dimensions, rather than marketing labels, determine the calculation.
References
Edmund Optics — Focal length and field of view · Nikon — Exposure · Cambridge in Colour — Depth of field
Frequently asked questions
How accurate are the calculations?
Enter focal length in millimetres, aperture, circle of confusion and subject distance. This thin-lens model estimates acceptable sharpness rather than a hard boundary. A smaller circle of confusion demands stricter sharpness. Distances are measured from the lens principal plane; macro magnification, pupil ratio, diffraction and lens-specific behavior are excluded.
Where is my shot list stored?
Create an establishing view, a main subject and a detail shot. Load example appends three editable shots. Up to 200 shots are saved in this browser; changing devices or clearing browser data will not preserve them. Export regularly if the plan matters.