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Image Plate Scale

by Roger N. Clark

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Introduction

Plate scale is a term which originated with film glass plates used over a hundred years ago. It is usually given as angular size per unit length on the glass plate. For example, degrees per millimeter, arc-minutes per millimeter, or arc-seconds per millimeter. If the subject distance is known, it can be expressed as the linear size at the subject on the sensor, for example, meters (on the subject) per millimeter on the sensor.

With modern digital cameras, plate scale can also be expressed in pixels, as in arc-seconds per pixel. Then if one knows the angular size of a subject (e.g. the Moon, a planet, or other astronomical object), the size in pixels can be calculated. If one knows the size and distance for a terrestrial subject, e.g. a bird that is 3 feet tall at a distance of 50 yards, the size in pixels can be calculated. Alternatively, with the lens focal distance recorded in the exif data, one can determine the size of a subject, e.g. how long are the claws on that grizzly bear?

Image Plate Scale

plate scale = 206265 * pixel pitch in mm / focal length in mm (result in arc-seconds per pixel).

The 206265 is the number of arc-seconds in one radian.

Without the 206265 factor, the plate scale is in radians:

plate scale radians = pixel pitch in mm / focal length in mm (result in radians per pixel).

Subject Plate Scale = range * pixel pitch in mm / focal length in mm (result in units in range per pixel),

for example, if the range is 500 meters, the focal length is 500 mm, and the pixel size is 5 microns (0.005 mm), the Subject Plate Scale = 500 meters * (0.005mm/500mm) = 0.005 meters/pixel = 5 mm /pixel

Examples:

Nikon D800 with 4.9 micron pixels (0.0049 mm) with a 600 mm lens:
plate scale = 206265 * 0.0049 / 600 = 1.7 arc-seconds.

Canon 7D with 4.3 microns pixels (0.0043 mm) with a 500 mm lens:
plate scale = 206265 * 0.0043 / 500 = 1.77 arc-seconds.

Canon 5D Mark II with 6.4 microns pixels (0.0064 mm) with a 500 mm lens:
plate scale = 206265 * 0.0064 / 500 = 2.6 arc-seconds.

Subject Size

Subject size = #pixels length on subject * Subject Plate Scale

Subject size = #pixels length on subject * range * pixel pitch in mm / focal length in mm

Example:

A grizzly bear's claw measures 300 pixels at a range of 50 meters with a 500 mm focal length lens (0.5 meter) and 5-micron pixels. How long are the claws?

claw size = 300 pixels * 50 meters * 0.005 mm pixel / 500 mm focal length = 0.15 meter = 150 mm = 5.9 inches.

Subject Distance

Say you know the subject's size, but want to know the distance, or how to plan for a certain size on the sensor. Say one wants X pixels on the subject, and you want to know how close you need to get with a certain lens.

Angular size of the subject = plate scale * number of pixels on the subject. (result in src-seconds)

Distance to subject = subject size / tangent(Angular size of the subject in arc-sec / 3600)
Distance to subject = subject size / tangent(pixels on subject * plate scale / 3600)

Example. 500 mm lens on a Nikon D800 with 4.88 micron pixels (see table, below) has a plate scale = 2.01 arc-sec/pixel. For a subject 2 meters long and 2000 pixels on the sensor, the distance would be:
distance = 2 meters / tan (2000 pixels * 2.01 arc-sec/pixel / 3600)
distance = 2 meters / tan (1.1167 degrees) = 2 / 0.019492
distance = 102.6 meters

A simplification, valid for small angles, like those imaged with telephoto lenses is to approximate the tangent by computing the size in radians. Example:
distance = 2 meters / (2000 pixels * 2.01 arc-sec/pixel /206265 arc-sec/radian)
distance = 2 meters / 0.0194895 = distance = 102.6 meters
Note the factor 0.0194895 is very close to the correct factor of 0.019492, and I would round the number to 0.0195 and is accurate to better than 0.1 meter, which should be more than accurate for most applications.

One can substitute the plate scale equation into the subject distance equation, and for telephoto lenses the Subject Distance equation reduces to:

Subject Distance = subject size / (pixels on subject * pixel size / focal length)

where the focal length and pixel size must be in the same units, like mm.

Resolution

The plate scale is also often used to indicate resolution. Real resolution is slightly less due to diffraction, assuming no other aberrations (yes on a perfect 600 mm f/4 lens, diffraction at f/4 will have an effect on fine detail contrast). Below 2 arc-seconds, atmospheric turbulence will often become a factor for distant subject (even a bird at 50 yards could be affected). As one approaches 1-arc-second, atmospheric turbulence usually becomes a dominant factor in detail on the subject (e.g. A Nikon D800 + 600 mm + 2x TC is 0.84 arc-seconds / pixel).

The angular resolution equation above illustrates another factor. Photographers seem fixated on focal length. But the above equation shows to get the same angular resolution, pixel pitch and focal length are interchangeable. Thus a camera "A" with 1.4x smaller pixels than camera "B" will be no different if camera B was used with a 1.4x TC versus camera A with the same lens and no TC. And for the same exposure time, will give the same noise and also same depth of field.

Plate Scales

      Table 1: Example Plate Scales

Canon 7D Mark II:
pixel=  4.09 microns  FL=   10 mm  plate scale =   84.36 arc-sec/pixel
pixel=  4.09 microns  FL=   15 mm  plate scale =   56.24 arc-sec/pixel
pixel=  4.09 microns  FL=   20 mm  plate scale =   42.18 arc-sec/pixel
pixel=  4.09 microns  FL=   24 mm  plate scale =   35.15 arc-sec/pixel
pixel=  4.09 microns  FL=   28 mm  plate scale =   30.13 arc-sec/pixel
pixel=  4.09 microns  FL=   35 mm  plate scale =   24.10 arc-sec/pixel
pixel=  4.09 microns  FL=   50 mm  plate scale =   16.87 arc-sec/pixel
pixel=  4.09 microns  FL=   85 mm  plate scale =    9.92 arc-sec/pixel
pixel=  4.09 microns  FL=  100 mm  plate scale =    8.44 arc-sec/pixel
pixel=  4.09 microns  FL=  135 mm  plate scale =    6.25 arc-sec/pixel
pixel=  4.09 microns  FL=  180 mm  plate scale =    4.69 arc-sec/pixel
pixel=  4.09 microns  FL=  200 mm  plate scale =    4.22 arc-sec/pixel
pixel=  4.09 microns  FL=  300 mm  plate scale =    2.81 arc-sec/pixel
pixel=  4.09 microns  FL=  400 mm  plate scale =    2.11 arc-sec/pixel
pixel=  4.09 microns  FL=  500 mm  plate scale =    1.69 arc-sec/pixel
pixel=  4.09 microns  FL=  600 mm  plate scale =    1.41 arc-sec/pixel
pixel=  4.09 microns  FL=  700 mm  plate scale =    1.21 arc-sec/pixel
pixel=  4.09 microns  FL=  800 mm  plate scale =    1.05 arc-sec/pixel
pixel=  4.09 microns  FL= 1000 mm  plate scale =    0.84 arc-sec/pixel
pixel=  4.09 microns  FL= 1200 mm  plate scale =    0.70 arc-sec/pixel
pixel=  4.09 microns  FL= 1400 mm  plate scale =    0.60 arc-sec/pixel
pixel=  4.09 microns  FL= 2000 mm  plate scale =    0.42 arc-sec/pixel


Canon 7D, 60D, 650D
pixel=  4.30 microns  FL=   10 mm  plate scale =   88.69 arc-sec/pixel
pixel=  4.30 microns  FL=   15 mm  plate scale =   59.13 arc-sec/pixel
pixel=  4.30 microns  FL=   20 mm  plate scale =   44.35 arc-sec/pixel
pixel=  4.30 microns  FL=   24 mm  plate scale =   36.96 arc-sec/pixel
pixel=  4.30 microns  FL=   28 mm  plate scale =   31.68 arc-sec/pixel
pixel=  4.30 microns  FL=   35 mm  plate scale =   25.34 arc-sec/pixel
pixel=  4.30 microns  FL=   50 mm  plate scale =   17.74 arc-sec/pixel
pixel=  4.30 microns  FL=   85 mm  plate scale =   10.43 arc-sec/pixel
pixel=  4.30 microns  FL=  100 mm  plate scale =    8.87 arc-sec/pixel
pixel=  4.30 microns  FL=  135 mm  plate scale =    6.57 arc-sec/pixel
pixel=  4.30 microns  FL=  180 mm  plate scale =    4.93 arc-sec/pixel
pixel=  4.30 microns  FL=  200 mm  plate scale =    4.43 arc-sec/pixel
pixel=  4.30 microns  FL=  300 mm  plate scale =    2.96 arc-sec/pixel
pixel=  4.30 microns  FL=  400 mm  plate scale =    2.22 arc-sec/pixel
pixel=  4.30 microns  FL=  500 mm  plate scale =    1.77 arc-sec/pixel
pixel=  4.30 microns  FL=  600 mm  plate scale =    1.48 arc-sec/pixel
pixel=  4.30 microns  FL=  700 mm  plate scale =    1.27 arc-sec/pixel
pixel=  4.30 microns  FL=  800 mm  plate scale =    1.11 arc-sec/pixel
pixel=  4.30 microns  FL= 1000 mm  plate scale =    0.89 arc-sec/pixel
pixel=  4.30 microns  FL= 1200 mm  plate scale =    0.74 arc-sec/pixel
pixel=  4.30 microns  FL= 1400 mm  plate scale =    0.63 arc-sec/pixel
pixel=  4.30 microns  FL= 2000 mm  plate scale =    0.44 arc-sec/pixel

Nikon D800, 800e
pixel=  4.88 microns  FL=   10 mm  plate scale =  100.66 arc-sec/pixel
pixel=  4.88 microns  FL=   15 mm  plate scale =   67.10 arc-sec/pixel
pixel=  4.88 microns  FL=   20 mm  plate scale =   50.33 arc-sec/pixel
pixel=  4.88 microns  FL=   24 mm  plate scale =   41.94 arc-sec/pixel
pixel=  4.88 microns  FL=   28 mm  plate scale =   35.95 arc-sec/pixel
pixel=  4.88 microns  FL=   35 mm  plate scale =   28.76 arc-sec/pixel
pixel=  4.88 microns  FL=   50 mm  plate scale =   20.13 arc-sec/pixel
pixel=  4.88 microns  FL=   85 mm  plate scale =   11.84 arc-sec/pixel
pixel=  4.88 microns  FL=  100 mm  plate scale =   10.07 arc-sec/pixel
pixel=  4.88 microns  FL=  135 mm  plate scale =    7.46 arc-sec/pixel
pixel=  4.88 microns  FL=  180 mm  plate scale =    5.59 arc-sec/pixel
pixel=  4.88 microns  FL=  200 mm  plate scale =    5.03 arc-sec/pixel
pixel=  4.88 microns  FL=  300 mm  plate scale =    3.36 arc-sec/pixel
pixel=  4.88 microns  FL=  400 mm  plate scale =    2.52 arc-sec/pixel
pixel=  4.88 microns  FL=  500 mm  plate scale =    2.01 arc-sec/pixel
pixel=  4.88 microns  FL=  600 mm  plate scale =    1.68 arc-sec/pixel
pixel=  4.88 microns  FL=  700 mm  plate scale =    1.44 arc-sec/pixel
pixel=  4.88 microns  FL=  800 mm  plate scale =    1.26 arc-sec/pixel
pixel=  4.88 microns  FL= 1000 mm  plate scale =    1.01 arc-sec/pixel
pixel=  4.88 microns  FL= 1200 mm  plate scale =    0.84 arc-sec/pixel
pixel=  4.88 microns  FL= 1400 mm  plate scale =    0.72 arc-sec/pixel
pixel=  4.88 microns  FL= 2000 mm  plate scale =    0.50 arc-sec/pixel

Pentax K20D
pixel=  5.00 microns  FL=   10 mm  plate scale =  103.13 arc-sec/pixel
pixel=  5.00 microns  FL=   15 mm  plate scale =   68.75 arc-sec/pixel
pixel=  5.00 microns  FL=   20 mm  plate scale =   51.57 arc-sec/pixel
pixel=  5.00 microns  FL=   24 mm  plate scale =   42.97 arc-sec/pixel
pixel=  5.00 microns  FL=   28 mm  plate scale =   36.83 arc-sec/pixel
pixel=  5.00 microns  FL=   35 mm  plate scale =   29.47 arc-sec/pixel
pixel=  5.00 microns  FL=   50 mm  plate scale =   20.63 arc-sec/pixel
pixel=  5.00 microns  FL=   85 mm  plate scale =   12.13 arc-sec/pixel
pixel=  5.00 microns  FL=  100 mm  plate scale =   10.31 arc-sec/pixel
pixel=  5.00 microns  FL=  135 mm  plate scale =    7.64 arc-sec/pixel
pixel=  5.00 microns  FL=  180 mm  plate scale =    5.73 arc-sec/pixel
pixel=  5.00 microns  FL=  200 mm  plate scale =    5.16 arc-sec/pixel
pixel=  5.00 microns  FL=  300 mm  plate scale =    3.44 arc-sec/pixel
pixel=  5.00 microns  FL=  400 mm  plate scale =    2.58 arc-sec/pixel
pixel=  5.00 microns  FL=  500 mm  plate scale =    2.06 arc-sec/pixel
pixel=  5.00 microns  FL=  600 mm  plate scale =    1.72 arc-sec/pixel
pixel=  5.00 microns  FL=  700 mm  plate scale =    1.47 arc-sec/pixel
pixel=  5.00 microns  FL=  800 mm  plate scale =    1.29 arc-sec/pixel
pixel=  5.00 microns  FL= 1000 mm  plate scale =    1.03 arc-sec/pixel
pixel=  5.00 microns  FL= 1200 mm  plate scale =    0.86 arc-sec/pixel
pixel=  5.00 microns  FL= 1400 mm  plate scale =    0.74 arc-sec/pixel
pixel=  5.00 microns  FL= 2000 mm  plate scale =    0.52 arc-sec/pixel

Canon 1D Mark IV, 400D, 1000D, 40D
pixel=  5.70 microns  FL=   10 mm  plate scale =  117.57 arc-sec/pixel
pixel=  5.70 microns  FL=   15 mm  plate scale =   78.38 arc-sec/pixel
pixel=  5.70 microns  FL=   20 mm  plate scale =   58.79 arc-sec/pixel
pixel=  5.70 microns  FL=   24 mm  plate scale =   48.99 arc-sec/pixel
pixel=  5.70 microns  FL=   28 mm  plate scale =   41.99 arc-sec/pixel
pixel=  5.70 microns  FL=   35 mm  plate scale =   33.59 arc-sec/pixel
pixel=  5.70 microns  FL=   50 mm  plate scale =   23.51 arc-sec/pixel
pixel=  5.70 microns  FL=   85 mm  plate scale =   13.83 arc-sec/pixel
pixel=  5.70 microns  FL=  100 mm  plate scale =   11.76 arc-sec/pixel
pixel=  5.70 microns  FL=  135 mm  plate scale =    8.71 arc-sec/pixel
pixel=  5.70 microns  FL=  180 mm  plate scale =    6.53 arc-sec/pixel
pixel=  5.70 microns  FL=  200 mm  plate scale =    5.88 arc-sec/pixel
pixel=  5.70 microns  FL=  300 mm  plate scale =    3.92 arc-sec/pixel
pixel=  5.70 microns  FL=  400 mm  plate scale =    2.94 arc-sec/pixel
pixel=  5.70 microns  FL=  500 mm  plate scale =    2.35 arc-sec/pixel
pixel=  5.70 microns  FL=  600 mm  plate scale =    1.96 arc-sec/pixel
pixel=  5.70 microns  FL=  700 mm  plate scale =    1.68 arc-sec/pixel
pixel=  5.70 microns  FL=  800 mm  plate scale =    1.47 arc-sec/pixel
pixel=  5.70 microns  FL= 1000 mm  plate scale =    1.18 arc-sec/pixel
pixel=  5.70 microns  FL= 1200 mm  plate scale =    0.98 arc-sec/pixel
pixel=  5.70 microns  FL= 1400 mm  plate scale =    0.84 arc-sec/pixel
pixel=  5.70 microns  FL= 2000 mm  plate scale =    0.59 arc-sec/pixel

Canon 1Ds Mark III, 5D Mark II, 20D, 30D, 20Da, 350D
pixel=  6.40 microns  FL=   10 mm  plate scale =  132.01 arc-sec/pixel
pixel=  6.40 microns  FL=   15 mm  plate scale =   88.01 arc-sec/pixel
pixel=  6.40 microns  FL=   20 mm  plate scale =   66.00 arc-sec/pixel
pixel=  6.40 microns  FL=   24 mm  plate scale =   55.00 arc-sec/pixel
pixel=  6.40 microns  FL=   28 mm  plate scale =   47.15 arc-sec/pixel
pixel=  6.40 microns  FL=   35 mm  plate scale =   37.72 arc-sec/pixel
pixel=  6.40 microns  FL=   50 mm  plate scale =   26.40 arc-sec/pixel
pixel=  6.40 microns  FL=   85 mm  plate scale =   15.53 arc-sec/pixel
pixel=  6.40 microns  FL=  100 mm  plate scale =   13.20 arc-sec/pixel
pixel=  6.40 microns  FL=  135 mm  plate scale =    9.78 arc-sec/pixel
pixel=  6.40 microns  FL=  180 mm  plate scale =    7.33 arc-sec/pixel
pixel=  6.40 microns  FL=  200 mm  plate scale =    6.60 arc-sec/pixel
pixel=  6.40 microns  FL=  300 mm  plate scale =    4.40 arc-sec/pixel
pixel=  6.40 microns  FL=  400 mm  plate scale =    3.30 arc-sec/pixel
pixel=  6.40 microns  FL=  500 mm  plate scale =    2.64 arc-sec/pixel
pixel=  6.40 microns  FL=  600 mm  plate scale =    2.20 arc-sec/pixel
pixel=  6.40 microns  FL=  700 mm  plate scale =    1.89 arc-sec/pixel
pixel=  6.40 microns  FL=  800 mm  plate scale =    1.65 arc-sec/pixel
pixel=  6.40 microns  FL= 1000 mm  plate scale =    1.32 arc-sec/pixel
pixel=  6.40 microns  FL= 1200 mm  plate scale =    1.10 arc-sec/pixel
pixel=  6.40 microns  FL= 1400 mm  plate scale =    0.94 arc-sec/pixel
pixel=  6.40 microns  FL= 2000 mm  plate scale =    0.66 arc-sec/pixel

Canon 6D
pixel=  6.58 microns  FL=   10 mm  plate scale =  135.72 arc-sec/pixel
pixel=  6.58 microns  FL=   15 mm  plate scale =   90.48 arc-sec/pixel
pixel=  6.58 microns  FL=   20 mm  plate scale =   67.86 arc-sec/pixel
pixel=  6.58 microns  FL=   24 mm  plate scale =   56.55 arc-sec/pixel
pixel=  6.58 microns  FL=   28 mm  plate scale =   48.47 arc-sec/pixel
pixel=  6.58 microns  FL=   35 mm  plate scale =   38.78 arc-sec/pixel
pixel=  6.58 microns  FL=   50 mm  plate scale =   27.14 arc-sec/pixel
pixel=  6.58 microns  FL=   85 mm  plate scale =   15.97 arc-sec/pixel
pixel=  6.58 microns  FL=  100 mm  plate scale =   13.57 arc-sec/pixel
pixel=  6.58 microns  FL=  135 mm  plate scale =   10.05 arc-sec/pixel
pixel=  6.58 microns  FL=  180 mm  plate scale =    7.54 arc-sec/pixel
pixel=  6.58 microns  FL=  200 mm  plate scale =    6.79 arc-sec/pixel
pixel=  6.58 microns  FL=  300 mm  plate scale =    4.52 arc-sec/pixel
pixel=  6.58 microns  FL=  400 mm  plate scale =    3.39 arc-sec/pixel
pixel=  6.58 microns  FL=  500 mm  plate scale =    2.71 arc-sec/pixel
pixel=  6.58 microns  FL=  600 mm  plate scale =    2.26 arc-sec/pixel
pixel=  6.58 microns  FL=  700 mm  plate scale =    1.94 arc-sec/pixel
pixel=  6.58 microns  FL=  800 mm  plate scale =    1.70 arc-sec/pixel
pixel=  6.58 microns  FL= 1000 mm  plate scale =    1.36 arc-sec/pixel
pixel=  6.58 microns  FL= 1200 mm  plate scale =    1.13 arc-sec/pixel
pixel=  6.58 microns  FL= 1400 mm  plate scale =    0.97 arc-sec/pixel
pixel=  6.58 microns  FL= 2000 mm  plate scale =    0.68 arc-sec/pixel

Canon 1DX
pixel=  6.90 microns  FL=   10 mm  plate scale =  142.32 arc-sec/pixel
pixel=  6.90 microns  FL=   15 mm  plate scale =   94.88 arc-sec/pixel
pixel=  6.90 microns  FL=   20 mm  plate scale =   71.16 arc-sec/pixel
pixel=  6.90 microns  FL=   24 mm  plate scale =   59.30 arc-sec/pixel
pixel=  6.90 microns  FL=   28 mm  plate scale =   50.83 arc-sec/pixel
pixel=  6.90 microns  FL=   35 mm  plate scale =   40.66 arc-sec/pixel
pixel=  6.90 microns  FL=   50 mm  plate scale =   28.46 arc-sec/pixel
pixel=  6.90 microns  FL=   85 mm  plate scale =   16.74 arc-sec/pixel
pixel=  6.90 microns  FL=  100 mm  plate scale =   14.23 arc-sec/pixel
pixel=  6.90 microns  FL=  135 mm  plate scale =   10.54 arc-sec/pixel
pixel=  6.90 microns  FL=  180 mm  plate scale =    7.91 arc-sec/pixel
pixel=  6.90 microns  FL=  200 mm  plate scale =    7.12 arc-sec/pixel
pixel=  6.90 microns  FL=  300 mm  plate scale =    4.74 arc-sec/pixel
pixel=  6.90 microns  FL=  400 mm  plate scale =    3.56 arc-sec/pixel
pixel=  6.90 microns  FL=  500 mm  plate scale =    2.85 arc-sec/pixel
pixel=  6.90 microns  FL=  600 mm  plate scale =    2.37 arc-sec/pixel
pixel=  6.90 microns  FL=  700 mm  plate scale =    2.03 arc-sec/pixel
pixel=  6.90 microns  FL=  800 mm  plate scale =    1.78 arc-sec/pixel
pixel=  6.90 microns  FL= 1000 mm  plate scale =    1.42 arc-sec/pixel
pixel=  6.90 microns  FL= 1200 mm  plate scale =    1.19 arc-sec/pixel
pixel=  6.90 microns  FL= 1400 mm  plate scale =    1.02 arc-sec/pixel
pixel=  6.90 microns  FL= 2000 mm  plate scale =    0.71 arc-sec/pixel

Canon 10D, 300D
pixel=  7.40 microns  FL=   10 mm  plate scale =  152.64 arc-sec/pixel
pixel=  7.40 microns  FL=   15 mm  plate scale =  101.76 arc-sec/pixel
pixel=  7.40 microns  FL=   20 mm  plate scale =   76.32 arc-sec/pixel
pixel=  7.40 microns  FL=   24 mm  plate scale =   63.60 arc-sec/pixel
pixel=  7.40 microns  FL=   28 mm  plate scale =   54.51 arc-sec/pixel
pixel=  7.40 microns  FL=   35 mm  plate scale =   43.61 arc-sec/pixel
pixel=  7.40 microns  FL=   50 mm  plate scale =   30.53 arc-sec/pixel
pixel=  7.40 microns  FL=   85 mm  plate scale =   17.96 arc-sec/pixel
pixel=  7.40 microns  FL=  100 mm  plate scale =   15.26 arc-sec/pixel
pixel=  7.40 microns  FL=  135 mm  plate scale =   11.31 arc-sec/pixel
pixel=  7.40 microns  FL=  180 mm  plate scale =    8.48 arc-sec/pixel
pixel=  7.40 microns  FL=  200 mm  plate scale =    7.63 arc-sec/pixel
pixel=  7.40 microns  FL=  300 mm  plate scale =    5.09 arc-sec/pixel
pixel=  7.40 microns  FL=  400 mm  plate scale =    3.82 arc-sec/pixel
pixel=  7.40 microns  FL=  500 mm  plate scale =    3.05 arc-sec/pixel
pixel=  7.40 microns  FL=  600 mm  plate scale =    2.54 arc-sec/pixel
pixel=  7.40 microns  FL=  700 mm  plate scale =    2.18 arc-sec/pixel
pixel=  7.40 microns  FL=  800 mm  plate scale =    1.91 arc-sec/pixel
pixel=  7.40 microns  FL= 1000 mm  plate scale =    1.53 arc-sec/pixel
pixel=  7.40 microns  FL= 1200 mm  plate scale =    1.27 arc-sec/pixel
pixel=  7.40 microns  FL= 1400 mm  plate scale =    1.09 arc-sec/pixel
pixel=  7.40 microns  FL= 2000 mm  plate scale =    0.76 arc-sec/pixel

Canon 1D Mark II, IIn
pixel=  8.20 microns  FL=   10 mm  plate scale =  169.14 arc-sec/pixel
pixel=  8.20 microns  FL=   15 mm  plate scale =  112.76 arc-sec/pixel
pixel=  8.20 microns  FL=   20 mm  plate scale =   84.57 arc-sec/pixel
pixel=  8.20 microns  FL=   24 mm  plate scale =   70.47 arc-sec/pixel
pixel=  8.20 microns  FL=   28 mm  plate scale =   60.41 arc-sec/pixel
pixel=  8.20 microns  FL=   35 mm  plate scale =   48.32 arc-sec/pixel
pixel=  8.20 microns  FL=   50 mm  plate scale =   33.83 arc-sec/pixel
pixel=  8.20 microns  FL=   85 mm  plate scale =   19.90 arc-sec/pixel
pixel=  8.20 microns  FL=  100 mm  plate scale =   16.91 arc-sec/pixel
pixel=  8.20 microns  FL=  135 mm  plate scale =   12.53 arc-sec/pixel
pixel=  8.20 microns  FL=  180 mm  plate scale =    9.40 arc-sec/pixel
pixel=  8.20 microns  FL=  200 mm  plate scale =    8.46 arc-sec/pixel
pixel=  8.20 microns  FL=  300 mm  plate scale =    5.64 arc-sec/pixel
pixel=  8.20 microns  FL=  400 mm  plate scale =    4.23 arc-sec/pixel
pixel=  8.20 microns  FL=  500 mm  plate scale =    3.38 arc-sec/pixel
pixel=  8.20 microns  FL=  600 mm  plate scale =    2.82 arc-sec/pixel
pixel=  8.20 microns  FL=  700 mm  plate scale =    2.42 arc-sec/pixel
pixel=  8.20 microns  FL=  800 mm  plate scale =    2.11 arc-sec/pixel
pixel=  8.20 microns  FL= 1000 mm  plate scale =    1.69 arc-sec/pixel
pixel=  8.20 microns  FL= 1200 mm  plate scale =    1.41 arc-sec/pixel
pixel=  8.20 microns  FL= 1400 mm  plate scale =    1.21 arc-sec/pixel
pixel=  8.20 microns  FL= 2000 mm  plate scale =    0.85 arc-sec/pixel

Nikon D3, D3s
pixel=  8.46 microns  FL=   10 mm  plate scale =  174.50 arc-sec/pixel
pixel=  8.46 microns  FL=   15 mm  plate scale =  116.33 arc-sec/pixel
pixel=  8.46 microns  FL=   20 mm  plate scale =   87.25 arc-sec/pixel
pixel=  8.46 microns  FL=   24 mm  plate scale =   72.71 arc-sec/pixel
pixel=  8.46 microns  FL=   28 mm  plate scale =   62.32 arc-sec/pixel
pixel=  8.46 microns  FL=   35 mm  plate scale =   49.86 arc-sec/pixel
pixel=  8.46 microns  FL=   50 mm  plate scale =   34.90 arc-sec/pixel
pixel=  8.46 microns  FL=   85 mm  plate scale =   20.53 arc-sec/pixel
pixel=  8.46 microns  FL=  100 mm  plate scale =   17.45 arc-sec/pixel
pixel=  8.46 microns  FL=  135 mm  plate scale =   12.93 arc-sec/pixel
pixel=  8.46 microns  FL=  180 mm  plate scale =    9.69 arc-sec/pixel
pixel=  8.46 microns  FL=  200 mm  plate scale =    8.73 arc-sec/pixel
pixel=  8.46 microns  FL=  300 mm  plate scale =    5.82 arc-sec/pixel
pixel=  8.46 microns  FL=  400 mm  plate scale =    4.36 arc-sec/pixel
pixel=  8.46 microns  FL=  500 mm  plate scale =    3.49 arc-sec/pixel
pixel=  8.46 microns  FL=  600 mm  plate scale =    2.91 arc-sec/pixel
pixel=  8.46 microns  FL=  700 mm  plate scale =    2.49 arc-sec/pixel
pixel=  8.46 microns  FL=  800 mm  plate scale =    2.18 arc-sec/pixel
pixel=  8.46 microns  FL= 1000 mm  plate scale =    1.75 arc-sec/pixel
pixel=  8.46 microns  FL= 1200 mm  plate scale =    1.45 arc-sec/pixel
pixel=  8.46 microns  FL= 1400 mm  plate scale =    1.25 arc-sec/pixel
pixel=  8.46 microns  FL= 2000 mm  plate scale =    0.87 arc-sec/pixel


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http://www.clarkvision.com/articles/platescale

First Published September 7, 2012
Last updated March 22, 2015.