if you just want to try one relatively inexpensive try to find a pinhole version. i've used both (bellows and pinhole) and the pinhole gives you something of an idea of what you're dealing with. I think i saw some on B&H a while back. (don't hold me to that)
apparently i'm a karmaloop rep. use this to get cash off, SS32258
Remember this kids! The higher your post count, the bigger your penis is!
1: Go to google.
2: Type in "define:kaster"
3:Press enter. Read