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What it frames

The Leica SL3-P with the TTArtisan AF 40mm f/2, 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.

40mm on the Leica SL3-P frames 4.5 m × 3 m at 5 m: like 40mm on full frame, 48° across.

24mm eq.50mm eq.135mm eq.40mm · like 40mm on full frame4.5 m × 3 m at 5 m
The subject is 5 m away; things behind it are drawn smaller, as the camera sees them.
Inside the frame: the picture you would get.

The numbers

  • Frame at 5 m4.5 m × 3 m
  • Full-frame equivalent40mm
  • Angle of view48° × 33°, 57° diagonal
  • Depth of field at f/24.24 m to 6.09 m (1.85 m)
  • Depth of field at f/82.91 m to 17.6 m (14.7 m)
  • Hyperfocal at f/227.8 m
  • Hyperfocal at f/86.97 m
  • Circle of confusion0.029 mm
f/24.24 m to 6.09 m (1.85 m)f/82.91 m to 17.6 m (14.7 m)camerasubject, 5 m10 m
Depth of field: what is acceptably sharp, wide open and at f/8, focused on the subject.

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.