Olympus-OM
[Top] [All Lists]

Re: [OM] Film scanner on the cheap?

Subject: Re: [OM] Film scanner on the cheap?
From: HI100@xxxxxxx
Date: Mon, 20 Sep 1999 02:15:28 EDT
In a message dated 9/19/99 5:42:55 PM Pacific Daylight Time, norcutt@xxxxxxx 
writes:
<< I don't think the scanner could handle a
 virtual image floating in the air.  Of course, if we're gonna just cut
 the wires we can also just grind the glass cause this 49 dollar scanner
 is already a gonner anyhow.  Even with the ground glass Warren may have
 a valid point.  There may be reflections coming off the bottom of the
 case which need to be suppressed by painting the interior black or,
 since it's a gonner anyhow maybe we can just remove the bottom. >>

Clearly unless you added some refractive optics you must use ground glass. 
This is the same as a view camera so maybe you could get a spare for a large 
view camera.(costly?) For experimenting (moderate quality) a piece of etched 
Mylar as used for old engineering ink drawings would probably work. I bought 
a small sheet of ground glass when I was in High school for a homebrew 
optical system so it must be cheap. To get it really bright may require 
special etching/grinding : this is the same issue as with viewfinder screens 
for SLR's. The "Etch" makes a big difference to brightness and  resolution. 
(a trade off) Alternately rear projection screens removed from a an old 
fashioned salesmans portable movie projector might be ideal. I think the 
issue of lack of contrast in the internal reflections of the box may have 
been partiallty addressed in the scanner design in the sense that the 
scanning head screens the portion of the image and an inch or two on either 
side from stray light reflected from the base. I believe (but have never 
checked ) the scanners use reflective rather than refractive optics to focus 
the line image down to the small CCD sensor arrary. 

Tim Hughes
Hi100@xxxxxxx

< This message was delivered via the Olympus Mailing List >
< For questions, mailto:owner-olympus@xxxxxxxxxxxxxxx >
< Web Page: http://Zuiko.sls.bc.ca/swright/olympuslist.html >


<Prev in Thread] Current Thread [Next in Thread>
Sponsored by Tako
Impressum | Datenschutz