medium format 44x33 crop factor and field of view calculator
A medium format 44x33 sensor measures 44 by 33 mm, a diagonal of 55.00 mm. Against the full-frame diagonal of 43.27 mm that is a crop factor of 0.787. The "cropped" digital medium format used by most current systems.
The diagonal divided by this gives the acceptable blur circle. 1500 is the usual modern figure.
- Full-frame equivalent focal length
- 27.53
- Equivalent aperture for depth of field
- 2.203
- Sensor diagonal
- 55.000
- Sensor area
- 1452.00 mm2
- Full frame gathers this many times more light
- 0.595
- Horizontal field of view
- 64.305 degrees
- Vertical field of view
- 50.481 degrees
- Diagonal field of view
- 76.314 degrees
- Hyperfocal distance
- 11 967
- Depth of field
- 1584
- Frame width at the subject
- 3.771
Show the working
- Focal length = 35
- Aperture f-number = 2.8
- Subject distance = 3
- Circle of confusion divisor = 1500
- sensor_w = 44 = 44
- sensor_h = 33 = 33
- Sensor diagonal = hypot(44, 33) = 55
- Crop factor = 55 > 0 ? 43.266615305567875 / 55 : 0 = 0.786 666
- Full-frame equivalent focal length = 35 * 0.786 666 = 27.5333
- Equivalent aperture for depth of field = 2.8 * 0.786 666 = 2.202 66
- Sensor area = 44 * 33 = 1452
- Full frame gathers this many times more light = 1452 > 0 ? 864 / 1452 : 0 = 0.595 041
- Horizontal field of view = deg(2 * atan(44 / (2 * 35))) = 64.3046
- Vertical field of view = deg(2 * atan(33 / (2 * 35))) = 50.4811
- Diagonal field of view = deg(2 * atan(55 / (2 * 35))) = 76.3145
- coc = 55 / 1500 = 0.036 666 7
- Hyperfocal distance = 35^2 / (2.8 * 0.036 666 7) + 35 = 11 966.8
- near = 3*1000 * 11 966.8 / (11 966.8 + (3*1000 - 35)) = 2404.29
- far = 3*1000 < 11 966.8 ? 3*1000 * 11 966.8 / (11 966.8 - (3*1000 - 35)) : 1e9 = 3988.13
- Depth of field = 3988.13 >= 1e9 ? 1e9 : 3988.13 - 2404.29 = 1583.84
- Frame width at the subject = 35 > 0 ? 3 * 44 / 35 : 0 = 3.771 43
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.
The "cropped" digital medium format used by most current systems.
Equivalent focal lengths on medium format 44x33
| Lens | Full-frame equivalent |
|---|---|
| 12 mm | 9.4 mm |
| 16 mm | 12.6 mm |
| 24 mm | 18.9 mm |
| 35 mm | 27.5 mm |
| 50 mm | 39.3 mm |
| 85 mm | 66.9 mm |
| 135 mm | 106.2 mm |
| 200 mm | 157.3 mm |
Frequently asked
What is the crop factor of a medium format 44x33 sensor?
0.787, calculated from its 55.00 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.