What it frames
The OM System PEN with the Laowa 9mm f/2.8 Zero-D, over an 8.5 m tree and a 1.75 m person, with hills behind. 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 Micro Four Thirds sensor (17.3 x 13 mm) has a crop factor of 2, so the dashed frames are marked with the focal length that gives the same view on it.
9mm on the OM System PEN frames 38.4 m × 28.9 m at 20 m: like 18mm on full frame, 88° across.
The numbers
- Frame at 20 m38.4 m × 28.9 m
- Full-frame equivalent18mm
- Angle of view88° × 72°, 100° diagonal
- Depth of field at f/2.81.82 m to infinity (to infinity)
- Depth of field at f/868 cm to infinity (to infinity)
- Hyperfocal at f/2.82.01 m
- Hyperfocal at f/871 cm
- Circle of confusion0.014 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.