RE: filmscanners: LED Illumination for Film Scanners

["Austin Franklin" <darkroom@ix.netcom.com>]

> Ah, but the "dynamics" of a conventional enlarger
> are rather different from a film scanner, no?

It depends on what dynamics you are talking about.  Yes, as you say the
exposure time is less, but that's about it.

> I wonder if the Leaf benefits from that ridiculously
> huge bulb -- as opposed to the dinky little 4 inch
> F4T5 tube used in the older SprintScans and Microtek
> machines.

Being that it scans 4x5, it needs to use the "cleanest" area of a bulb at
least 4+ inches wide.  The ends of bulbs tend not to be near as uniform as
the middle.  I would agree it certainly is a lot larger than it needs to be
as far as illumination area goes!

Perhaps it has to do with controllability...that it is just easier to
control a larger tube than a smaller one, or perhaps it was the best bulb
available at the time.  I know it's a custom bulb, made from a stock
bulb...it has an area of the bulb unfrosted.  I'll ask next time I talk with
one of the original Leaf folks.  It also doesn't really matter that the bulb
is long or short, mechanically that is, it certainly isn't the determining
factor in the size of the unit.

BTW, I figured out a way to get 5080 PPI scans from it in MF mode...whether
they are any good or not, I don't know, but it'll be interesting to try it
out!  It's only true 5080 in one direction (direction of stage travel), the
other (CCD width) is just a simple avg across two adjacent pixels to double
the data...