ooo nice and broad topic there Alien8.
Just ordered myself a set of cheap and chearful (and hopefully not too crap) extension tubes off ebay, so maybe Ill have something from playing with them.
pretty hard to make a bad extension tube since they have no optics, might mess with your focus and metering systems but as long as your digital trial and error will see you through.
Stop. Macro time!
Might have to be lots and lots of trial and error, in fact the more the merrier lol Just a shame they aint turned up yet, but then I did only order them on the 2nd, be wants to play