I've had a set of Kenko Extension Tubes for a while but haven't really taken the time to learn how to use them properly. So today, I thought I'd give them a try, experimenting with different lenses to see what seemed to work best using the full 68 mm worth of tubes. This is my left index finger taken with the Tamron 28-75mm at 68mm, tripod mounted, cable release.

I've posted a few more extension tubes shots at the front of my macro gallery http://www.pbase.com/lowthian/macros