These images were taken when I first started trying out macro photography many years ago. I didn't have a proper macro lens, so I used extension tubes on a 50mm portrait lens. They attach between the camera body and lens and will allow much closer focusing. Its an inexpensive way to get into macro with a DSLR, and they can be a bit tricky to use. The focus is fixed, so to get what you want, it involves moving the camera towards and away from your subject until it comes into focus. It is a great way to learn, as you really appreciate framing things and using depth of field to get the image you want.
Nikon D90 1/200 sec. f/14 ISO-160 at 50mm
Nikon D90 1/200 sec. f/14 ISO-160 at 50mm
Nikon D90 1/200 sec. f/14 ISO-160 at 50mm
Nikon D90 1/200 sec. f/14 ISO-160 at 50mm