Re: IR lighting

Jacqueline Chados (jackie@sri.webmate.com)
Thu, 15 Aug 1996 12:47:31 -0400 (EDT)


A quick and dirty infrared source is any ordinary incandescent lamp
powered at reduced voltage using a variac or some other means. For best
results you can add an infrared-passing visible-blocking filter in front
of the lamp. This let's you run the lamp hotter for more output while
having the visible component removed. You can get some very inexpensive
plastic substrate filters from almost any optical supply house. One thing
with the plastic filters is that you have to be careful not to overheat them.

The improved sharpness you observe in the camer's image when using the IR
source is likely due to reduced chromatic aberration as the camera is now
detecting the image over a narrower band of wavelengths. You should notice
the increased sharpness if you use any type of narrower band illumination
such as a red-filtered lamp.

By the way. Speaking of Quick-cams. Does anyone have any experience
with this new D-CAM that is becoming available? It looks like it is the
same type of device as the color quick cam but with a few advantages. I
saw it at http://www.chest.com/value.html.

When I emailed the site that the price seemed a few dollars too high, they
told me they are working with the manufacturer to lower the price to be
more competitive with the quick cam. They hope to have the lower price in
a week or two. I'm thinking of getting one and I was wondering if anyone
out there has one yet.

Jackie