So you want to take REALLY close-up pictures but you can't afford a macro lens and all the paraphernalia that has to go with it to get the shots you want?
Not a problem.
Get hold of an old 50mm lens, doesn't matter what, all it needs is to have an aperture ring (all the old cheap ones do) and be about the same diameter as your lens mount. You also need a cardboard tube, the sort you would send a photo through the post in. Bung the lens in one end of the tube with the rear element sticking out and either push the other end up against your camera body, or if you want it a bit more stable, cut the inside out of a body cap, glue it into the tube and mount the whole lot to your SLR.
Normal set-up: Nikon D300s + 60mm Micro.
The results: not bad but not exactly what i was after.
The Royal Mail set-up: D300s + cardboard tube with a Pentax 50mm jammed in the end.
The results: no cropping, this is full frame. Had to adjust the levels a fair bit as contrast is lost due to the inside of the tube being somewhat less perfect than a nice lens and the focussing was a nightmare. Took a few shots before I realised I was in the pens ball so this one has me grinning at it.