Re: Nice Rig, HP, Ideas

[Brian Reynolds <reynolds@xxxxxxxxx>]

Sam wrote:
> 
> Another silly idea: If flatbed scanners are light sensitive, couldn't they
> be used for low sensitivety digital camera backs? I'm thinking of a large
> format stereo camera of course!
> 

Not a silly idea.  A couple of companies (Leaf is one of them I think)
make digital camera backs for large format (4x5) cameras that are
basically flat bed scanners that you attach to the camera.  You are
pretty much stuck using them in the studio because they need to be
tethered to a computer and power supply.  Subjects wind up being still
lifes (or commercial work) because if the subject moves the images is
useless (besides blurring on the multipass versions the color
seperations wouldn't line up).

I don't know how practical it would be to try and convert a desktop
scanner to this use.  They tend to be pretty heavy and the wrong size
for standard cameras.  They also require a pretty bright image (think
about how bright the light source in a scanner is).  There's also the
problem of figuring out where the scanner is focused.  Hand scanners
have been converted for use as astronomical cameras (instead of the
camera tracking the sky, the sky moves past the scanner).

By the way, digital cameras are not necessarily "faster" than film.  A
typical astronomical CCD camera is about 100ASA.  The reason CCDs are
used in astronomy (and other low light situations) is that their light
response curve is linear (unlike film).  This means they don't suffer
reciprosity failure (which can greatly extend exposure times).

-- 
Brian Reynolds                  | "Humans explore the Universe with five
reynolds@xxxxxxxxx              |   senses and call the adventure science."
http://www.panix.com/~reynolds/ | - Edwin P. Hubble