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| A Versatile Panoramic Scanner | |
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ScanCam Mark 2
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ScanCam Mark 2 takes high resolution panoramas using SLR camera lenses on an M42 (“Pentax screw”) mount. I can tilt the lens about 40 degrees up or down to put the “horizon line” pretty much anywhere I want in the image.
The electronics are from a 1200 DPI Umax Astra 5470 scanner. The CCD is 42mm long – almost the diagonal of a 35mm film frame -- and has 10,600 pixels, giving an effective resolution of 48 megapixels per 35mm frame. I usually scan at one-half, one-third or one-quarter of that resolution – 12, 5 or 3 Mpixel / frame.
The lens fork turns on a ball bearing hub driven by a homemade plastic worm gear. The ribbon cable wraps 3 times around the hub at home position and 2 times around after a full turn of the lens.
One revolution of the lens is 29,430 motor steps. This allows scanning at full resolution with my longest lens, a 55mm Takumar that covers 42 degrees vertically. I also use a 28mm Takumar covering 74 degrees, and a 16mm Zenitar fisheye covering 150 degrees.
The CCD board sits on a plastic cone that was once part of the scanner, under a light tight sheet metal cover. Inside the cone are an infrared blocking filter and a simple flap shutter, used to calibrate the CCD dark signal before each scan.
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