What it frames
The OM System OM-5 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 OM System OM-5 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.