Inspired by Colin's light table for portraits, I thought I'd try my own version - on the cheap. I turned one of my studio lamps towards the ceiling and balanced a sheet of white semi-transparent acrylic on top. Obviously, the amount of light from the flash head will be reduce, but there is still plenty to illuminate fom underneath. I used a Canon flash gun on a light stand, and fitted with a diffuser, to get the top light. Here is the setup. You can see the light coming through from the modelling lamp underneath the acrylic.
C&C welcome on any of these.
I tried a Lily flower, cut from the stem, and just resting on the acrylic. The light from underneath had to be balanced with the light coming from the overhead flash-gun and that did take some time to get right.
For this one I turned the flower upside-down (see the setup shot above) and used the same lighting. Then, in CS5 I rotated the shot to give the impression that I had shot it from underneath, but it has good lighting. I thought that was pretty sneaky!
For this final one I turned off the lights, and the acrylic sheet provided a very good reflection of the subject. This was also a stacked image - three manual focus shots stacked in CS5.