medium format 54x40 crop factor and field of view calculator
A medium format 54x40 sensor measures 54 by 40 mm, a diagonal of 67.20 mm. Against the full-frame diagonal of 43.27 mm that is a crop factor of 0.644.
The diagonal divided by this gives the acceptable blur circle. 1500 is the usual modern figure.
- Full-frame equivalent focal length
- 22.53
- Equivalent aperture for depth of field
- 1.803
- Sensor diagonal
- 67.201
- Sensor area
- 2160.00 mm2
- Full frame gathers this many times more light
- 0.400
- Horizontal field of view
- 75.295 degrees
- Vertical field of view
- 59.490 degrees
- Diagonal field of view
- 87.663 degrees
- Hyperfocal distance
- 9800
- Depth of field
- 1998
- Frame width at the subject
- 4.629
Show the working
- Focal length = 35
- Aperture f-number = 2.8
- Subject distance = 3
- Circle of confusion divisor = 1500
- sensor_w = 54 = 54
- sensor_h = 40 = 40
- Sensor diagonal = hypot(54, 40) = 67.2012
- Crop factor = 67.2012 > 0 ? 43.266615305567875 / 67.2012 : 0 = 0.643 837
- Full-frame equivalent focal length = 35 * 0.643 837 = 22.5343
- Equivalent aperture for depth of field = 2.8 * 0.643 837 = 1.802 74
- Sensor area = 54 * 40 = 2160
- Full frame gathers this many times more light = 2160 > 0 ? 864 / 2160 : 0 = 0.4
- Horizontal field of view = deg(2 * atan(54 / (2 * 35))) = 75.2952
- Vertical field of view = deg(2 * atan(40 / (2 * 35))) = 59.4898
- Diagonal field of view = deg(2 * atan(67.2012 / (2 * 35))) = 87.6627
- coc = 67.2012 / 1500 = 0.044 800 8
- Hyperfocal distance = 35^2 / (2.8 * 0.044 800 8) + 35 = 9800.45
- near = 3*1000 * 9800.45 / (9800.45 + (3*1000 - 35)) = 2303.2
- far = 3*1000 < 9800.45 ? 3*1000 * 9800.45 / (9800.45 - (3*1000 - 35)) : 1e9 = 4301.3
- Depth of field = 4301.3 >= 1e9 ? 1e9 : 4301.3 - 2303.2 = 1998.11
- Frame width at the subject = 35 > 0 ? 3 * 54 / 35 : 0 = 4.628 57
Values are shown to six significant figures here; the arithmetic itself runs on exact fractions and is only rounded where a number is printed.
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The formula
- crop factor = full-frame diagonal / sensor diagonal
- field of view = 2 arctan(sensor dimension / 2 focal length)
- hyperfocal distance = f^2 / (N c) + f
- equivalent aperture = aperture x crop factor, for depth of field and total light
Crop factor changes the framing, not the lens. A 50 mm lens is always a 50 mm lens; it just sees a smaller rectangle.
Equivalent aperture matters for depth of field and total light gathered, not for exposure. An f/2.8 lens meters as f/2.8 on any format.
The circle of confusion is a judgement about acceptable sharpness at a viewing size, not a physical constant.
Equivalent focal lengths on medium format 54x40
| Lens | Full-frame equivalent |
|---|---|
| 12 mm | 7.7 mm |
| 16 mm | 10.3 mm |
| 24 mm | 15.5 mm |
| 35 mm | 22.5 mm |
| 50 mm | 32.2 mm |
| 85 mm | 54.7 mm |
| 135 mm | 86.9 mm |
| 200 mm | 128.8 mm |
Frequently asked
What is the crop factor of a medium format 54x40 sensor?
0.644, calculated from its 67.20 mm diagonal against full frame at 43.27 mm.
Does a crop sensor make a lens longer?
No. The lens projects the same image; the smaller sensor simply records a smaller part of it, which looks like a longer lens.