This sounds neat.  Do the tunable filters in the Spot camera & from
Cambridge Research (are the latter used in the former?) have
disadvantages (or advantages) compared to traditional filters?  In terms
of bandpass, transmission, ability to capture the whole spectrum of
colors "faithfully", expense, aging, susceptibility to damage by arc or
halogen illumination, etc?

Thanks
Richard

>>> Ted Inoue <[log in to unmask]> 04/30/98 02:29pm >>>
If you are already using a Princeton monochrome camera, then you have
one of the most important components for high quality true color imaging.
The other two components needed are  a color selector and software to
merge three monochrome images into a true color one.

The Spot camera by Diagnostic instruments puts these pieces elegantly
into a single housing. By selecting the desired wavelength using a liquid
crystal tunable filter, it then takes three monochrome images sequentially,
one red, one green, and one blue.

For wavelength selection with your Princeton camera, you have at least
three options:
1) Use a liquid crystal filter assembly from Cambridge Research in
Massachusetts.
http://www.cri-inc.com/Pages/framesets/product_VS_rgb.html
2) Use the filter holders built into your microscope stand. Put red, green
and blue filters into the holders and manually select which image to
acquire. This is cumbersome.
3) Use a computerized filter wheel mounted: a) in front of the illuminator
or b) in front of the camera. Either will work well.

Depending on your budget and your current software capabilities, these
options all allow you to achieve some of the finest true color images
achievable digitally. As noted, Leaf makes an excellent, high resolution
camera, but its slow speed must be taken into consideration.

-Ted Inoue