Camera Comparisons:

http://www.martinmicroscope.com/Digital&Video.htm

 

Microscope Supplies :

http://www.tedpella.com

 

Interactive java applet on the darkfield condenser:

http://www.olympusmicro.com/primer/java/darkfield/cardioid/index.html

http://www.olympusmicro.com/primer/java/darkfield/abbe/index.html