Field of View

How it works

Framing depends on two numbers: the sensor's size and the lens's focal length. Everything here is computed from those two, then drawn on a photo whose own numbers are known.

Method

An ideal (rectilinear) lens projects the scene like a pinhole: the angle of view across one side is 2 × atan(side ÷ (2 × focal length)). A tighter frame from the same spot is exactly a centred crop of a wider photo, so any setup can be drawn as a rectangle on a wide reference photo.

Each reference photo was taken at a known focal length on a known sensor (read from its EXIF data) and is published uncropped, so its edges have known angles. A setup's rectangle is its own angle divided by the photo's, side by side, in tangent space. Frames wider than the photo make the view zoom out; the hatched margin is what the photo doesn't show.

"Equivalent focal length" uses the conventional crop factor (APS-C 1.5, Canon APS-C 1.6, Micro Four Thirds 2, 1-inch 2.7, medium format 0.79), which compares diagonals. The rectangles use the real sensor dimensions, so a 4:3 sensor is drawn taller and narrower than a 3:2 one at the same equivalent.

What it ignores

Camera and lens data

507 cameras and 1489 lenses (public specs only), imported on 2026-11-04 from the catalog of chiisai.camera

Reference photos