[filmscanners] RE: A partial fix for Minolta scanners?

["Mike Brown" <mike.brown@mindblown.com>]

Sounds good I will certainly be interested to see the details. I also have a
Dual Scan II & I must admit I've been wondering about whether I could
diffuse the light source.

I have been intending to see if Vuescan can be used to defocus scans
slightly. Has anyone tried that? I don't recall seeing any post on the
subject.

Mike Brown

> -----Original Message-----
> From: filmscanners_owner@halftone.co.uk
> [mailto:filmscanners_owner@halftone.co.uk]On Behalf Of Arthur Entlich
> Sent: 18 October 2002 10:23
> To: mike.brown@mindblown.com
> Subject: [filmscanners] A partial fix for Minolta scanners?
>
>
> As many of you know, I own a Minolta Dual Scan II.  Although I
> recommended this scanner  due to its lower cost and fairly good quality
> scans, I was unhappy with three aspects.
>
> 1) Quality control problems where one or more CCDs in one or more
> channels would be miscalibrated causing lines to appear across the scan
>
> 2) Something within the optical path which caused the scanner to produce
> scans which had exaggerated dust, dirt, scratches and grain, dissimilar
> from other scanners offering a cold cathode diffused light source.
>
> 3) occasional and intermittent mis-calibration causing a pink section
> down the center of negative scans.
>
> The other problems with this scanner are: slow USB connection and 12 bit
> A/D converter which allows for some shadow noise and problems getting
> detail out of the deep shadows.  These two issues have been addressed in
> the Minolta Elite II (with Firewire and 16 bit A/D converter) and the
> new Minolta Dual Scan III with new software and  16 bit A/D converter.
>
> For people who dodged the QC bullet and got one without "lazy sensor"
> lines, and for those who either do not have the calibration problems, or
> find the transient nature not much of an issue, I have some potential
> good news.
>
> As I have mentioned before, The Elite II and Pro medium format scanner
> have both had a software and firmware version upgrade which helps to
> take care so some of these elements.  However, the revision did not fix
> some of the optical problems, and no upgrade was provided for the Dual
> Scan II.
>
> Issue number (2) has been one of some conjecture.  WHy is it that a
> diffuse light source scanner is capturing so much surfaced  defect?  I
> suggested that it may be a matter of overfocusing the scan and
> surpassing the Nyquist limitations for this scanner, therefore
> introducing more noise and surface defects than it should.  I suggested
> a slight defocusing might help, and a control to allow for this would be
> nice in software.
>
> Some of you may know that Bo Wrangborg, owner of the Minolta Pro list,
> has been battling with Minolta for some time trying to get them to
> resolve this problem.  I got involved in some manners because of my
> ownership of the Dual Scan II and trying to get Minolta to acknowledge
> these difficulties.
>
> Recently Bo and a gent from Holland got together to see what could be
> done to resolve this problem with excessive surface defect and noise.
> It would appear that they have come up with an answer.  As we already
> know, from Nikon's use of LED lighting, collimated light sources cause
> considerable increase in visibility of dust, grain, dirt, scratches and
> grain.  What Bo and the other person did was to try diffusing the light
> source further by using some diffusion materials between the light
> source and the film.  The results are quite considerable in terms of
> improvement by reduction of these surface defects without damaging the
> image quality.  I have noticed slight color changes.  Bo suggests the
> only reason this can now be attempted is due to Minolta's new software
> offering an exposure adjustment.  However, I suspect that the problem
> might be able to be resolved by either placing a diffuser right at the
> light source, rather than between the film and the the light source (it
> is actually attached to the film holder in some manner right now), or
> also having the diffuser in the calibration slot of the holders so the
> CCDS are adjusted with the diffusion material as a standard for the
> light source.
>
> Bo has put together a web site showing the results of two different
> filter types.  I am not sure if the website is officially open to public
> traffic yet, so I will ask him, and if it is, you can take a look if
> interested in how the diffused lighting improved against the problems.
>
> I am wondering if Minolta has installed any sort of condenser or other
> method to collimate the lighting source, and if that isn't the problem.
>   The fact that a diffuser resolves the majority of the problem suggests
> they may have designed the lighting system incorrectly.
>
> Under any circumstances, if you own a Minolta Pro, Dual Scan II or Elite
> Scan II, (especially when using it with Kodachrome or B&W films) you may
> want to consider the use of a light diffuser.
>
> As soon as I get the OK, I will publish the website with more about this.
>
> Art
>
> ------------------------------------------------------------------
> ----------------------
> Unsubscribe by mail to listserver@halftone.co.uk, with
> 'unsubscribe filmscanners'
> or 'unsubscribe filmscanners_digest' (as appropriate) in the
> message title or body

----------------------------------------------------------------------------------------
Unsubscribe by mail to listserver@halftone.co.uk, with 'unsubscribe 
filmscanners'
or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or 
body