What it frames
The Fujifilm GFX Eterna 55 with the Fujifilm GF 250mm f/4 R LM OIS WR, 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. Its Medium format (44 x 33) sensor (43.8 x 32.9 mm) has a crop factor of 0.79, so the dashed frames are marked with the focal length that gives the same view on it.
250mm on the Fujifilm GFX Eterna 55 frames 2.63 m × 1.97 m at 15 m: like 198mm on full frame, 10° across.
The numbers
- Frame at 15 m2.63 m × 1.97 m
- Full-frame equivalent198mm
- Angle of view10° × 7.5°, 13° diagonal
- Depth of field at f/414.5 m to 15.5 m (1.04 m)
- Depth of field at f/814 m to 16.1 m (2.08 m)
- Hyperfocal at f/4428 m
- Hyperfocal at f/8214 m
- Circle of confusion0.037 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.