What it frames
The Panasonic Lumix G9 II with a 50mm lens (no lens chosen; depth of field at f/2.8), over a 1.75 m person in front of a wall with a window. 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.
50mm on the Panasonic Lumix G9 II frames 52 cm × 39 cm at 1.5 m: like 100mm on full frame, 20° across.
The numbers
- Frame at 1.5 m52 cm × 39 cm
- Full-frame equivalent100mm
- Angle of view20° × 15°, 24° diagonal
- Depth of field at f/2.81.47 m to 1.54 m (7 cm)
- Depth of field at f/81.41 m to 1.61 m (20 cm)
- Hyperfocal at f/2.861.9 m
- Hyperfocal at f/821.7 m
- 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.