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What it frames

The Leica SL3-P with the Sigma 300-600mm f/4 DG OS Sports, over a 30 cm bird on a 1 m fence post. 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.

300mm on the Leica SL3-P frames 1.8 m × 1.2 m at 15 m: like 300mm on full frame, 6.9° across.

24mm eq.50mm eq.135mm eq.300mm · like 300mm on full frame1.8 m × 1.2 m at 15 m
The subject is 15 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 15 m1.8 m × 1.2 m
  • Full-frame equivalent300mm
  • Angle of view6.9° × 4.6°, 8.2° diagonal
  • Depth of field at f/414.7 m to 15.3 m (57 cm)
  • Depth of field at f/814.5 m to 15.6 m (1.13 m)
  • Hyperfocal at f/4780 m
  • Hyperfocal at f/8390 m
  • Circle of confusion0.029 mm
f/414.7 m to 15.3 m (57 cm)f/814.5 m to 15.6 m (1.13 m)camerasubject, 15 m30 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.