What it frames
The Ricoh GR IIIx HDF with its built-in 26mm f/2.8 lens, over a 1.75 m person in a street, with a door, a parked car and buildings. Everything is drawn to scale: the solid frame is what the camera takes in, the dashed ones are 24, 50 and 135mm on full frame from the same spot. Its APS-C sensor (23.5 x 15.6 mm) has a crop factor of 1.5, so the dashed frames are marked with the focal length that gives the same view on it.
26mm on the Ricoh GR IIIx HDF frames 4.5 m × 2.99 m at 5 m: like 39mm on full frame, 48° across.
The numbers
- Frame at 5 m4.5 m × 2.99 m
- Full-frame equivalent39mm
- Angle of view48° × 33°, 57° diagonal
- Depth of field at f/2.83.61 m to 8.12 m (4.51 m)
- Depth of field at f/82.38 m to infinity (to infinity)
- Hyperfocal at f/2.813 m
- Hyperfocal at f/84.55 m
- Circle of confusion0.019 mm
How it is worked out
The frame at a distance is distance × sensor size ÷ focal length, across and up; the angle of view is 2 × atan(sensor size ÷ (2 × focal length)). Depth of field uses the thin-lens formulas: the hyperfocal distance H = f² ÷ (N × c) + f, the near limit s(H − f) ÷ (H + s − 2f) and the far limit s(H − f) ÷ (H − s), sharp to infinity from H on, with a circle of confusion c of the sensor diagonal ÷ 1500 and, on a zoom whose aperture changes, the maximum aperture taken linearly between its ends. These are for a rectilinear lens; a fisheye takes in more. Ask for this page with Accept: application/json for the numbers alone.