Polaroid ST-8E - Manual (Page 32)

Section 4 - Camera Hardware
Page 28
Camera
CCD Used Number of
Pixels
Pixel
Dims.
Array
Dimension
Read
Noise
Full Well
Capacity
Tracking
CCD
TC-211 192 x 164 13.75 x 16µ 2.6 x 2.6mm 12e - rms 150Ke -
ST-5C TC-255 320 x 240 10 x 10µ 3.2 x 2.4mm
20e
-
rms 50Ke
-
ST-237 TC-237 640 x 480 7.4 x 7.4µ 4.7 x 3.6mm
15e
-
rms 20Ke
-
STV TC-237 320 x 200 14.8 x 14.8 4.7 x 3.0mm 17e - rms 20Ke-
ST-6 TC-241 375 x 242 23 x 27µ 8.8 x 6.6mm 30e
-
rms 400Ke
-
ST-7E KAF0401E 765 x 510 9 x 9µ 6.9 x 4.6mm 15e- rms
50Ke
-
/100Ke
- 4
ST-8E KAF1602E 1530 x 1020 9 x 9µ 13.8 x 9.2mm 15e- rms 50Ke - /100Ke - 4
ST-9E KAF0261E 512 x 512 20 x 20µ 10.2 x 10.2mm 13e- rms 200Ke-
Table 4.3- CCD Differences
How these various specifications affect the average user is described in the following
paragraphs:
Number of Pixels - The number of pixels in the CCD affects the resolution of the final images.
The highest resolution device is best but it does not come without cost. Larger
CCDs cost more money and drive the system costs up. They are harder to cool,
require more memory to store images, take longer to readout, etc. With PCs and
Macintosh computers offering graphics resolutions of 320 x 200 to 640 x 480 with
good grey scale, the CCDs used in the SBIG cameras offer a good trade off
between cost and resolution, matching the computer's capabilities well.
Pixel Dimensions - The size of the individual pixels themselves really plays into the user's
selection of the system focal length. Smaller pixels and smaller CCDs require
shorter focal length telescopes to give the same field of view that larger CCDs
have with longer focal length telescopes. Smaller pixels can give images with
higher spatial resolution up to a point. When the pixel dimensions (in
arcseconds of field of view) get smaller than roughly half the seeing, decreasing
the pixel size is essentially throwing away resolution. Another aspect of small
pixels is that they have smaller full well capacities.
For your reference, if you want to determine the field of view for a pixel
or entire CCD sensor you can use the following formula:
Field of view (arcseconds) =
8.12x size (µm)
focal length (inches)
Field of view (arcseconds) =
20.6x size(um)
focal length (cm)
where size is the pixel dimension or CCD dimension in millimeters and the focal
4 The Kodak CCDs (KAF0400 and KAF1600) are available with or without Antiblooming Protection.
Units with the Antiblooming Protection have one-half the full well capacity of the units without it.