RE: Digital Cirkut Cam?

[Mike Sinclair <sinclair@xxxxxxxxxxxxx>]

Scott,

The best "cheap" scanner I have found lately that does a good job is the
Epson 636U (~$90 street). It has a 5100 element trilinear CCD, internal 12
bit digitizing, 600dpi intrinsic resolution and USB interface. This will
yield a maximum raw file size of ~105Mbytes. Also, the sensor is 42mm which
is ideal for digitizing the largest image circle from most 35mm lenses.

There are three (at least) problems with this approach (and applies to most
of the scanners on the market now). One is most of the inexpensive scanners
have little or no built in gamma compression. Typical contrasts on things
that flatbed scanners scan is usually less than 100:1 but if you point the
lens/sensor at the world, you'll get many orders of magnitude beyond this.
Another problem is calibration. Used to be most scanners would scan a
calibration sheet, store the result in the computer then use it for every
subsequent scan. New scanners calibrate by scanning a 8.5" white strip
before every scan. This requires you have an equivalent calibration setup in
your camera. Another problem is that most flatbed scanners have fixed
maximum scan lengths, usually around 11.5". Even if I use a Zenit 16mm
fisheye (www.russia2all.com  -$139), I need a longer scan , ~17", to give me
~square pixels, though having to change the scaling is not that bad. This
setup gives me ~180 x 360 degree scans.

Good luck and happy scanning.

-Mike-

-----Original Message-----
From: sperry@xxxxxxxxxxxxx [mailto:sperry@xxxxxxxxxxxxx]
Sent: Tuesday, November 07, 2000 6:29 AM
To: panorama-l@xxxxxxxxxxxxxxxxx
Subject: Digital Cirkut Cam?


While thinking of a winter project to do, I'm considering the feasibilty of
putting parts from a one pass CCD flatbed scanner in a homemade back that
will fit on a Cirkut camera outfit. Don't ask me why, but any suggestions
on how this could be done would be appreciated? A year or so ago I remember
a fellow on this list was building a digital panoramic camera with, if
memory serves me correctly, a Marstek hand held scanner. Are you still on
this list? If not does anyone else have his email address?

-Scott

-Scott Perry
-sperry@xxxxxxxxxxxxx