[filmscanners] Re: rebuild your scanner and get better results

["Major A" <andras@users.sourceforge.net>]

> Why would it be "technically very difficult to make it [LED intensity]
> variable"?  I believe the Nikon 8000 varies the LED intensity.

LED intensity is hard to control without feedback because their
response of intensity to voltage and current isn't linear. If you make
circuitry for controlling the LED output, you end up having unwanted
fluctuations, so it's better to leave it straight away (unless you
make a proper robust circuit, but that would cost more). It wouldn't
make too much sense anyway because what you want is as much light on
the CCD as you can.

As a matter of fact, the entire Nikon Coolscan line has
fixed-intensity LEDs, as one can conclude from reading the programming
specs (which aren't public).

  Andras

===========================================================================
Major Andras
    e-mail: andras@users.sourceforge.net
    www:    http://andras.webhop.org/
===========================================================================

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