This was tricky. This spider was no more than 3mm across and was climbing down a mirror in our bathroom.... right in the corner of the room. It was pretty hard to get a tripod in the corner and still harder to focus my "poor man's macro" gear on him. I use a Tamron 70-300mm lens with a Nikkor 50mm reverse mounted in front of it. It gives tons of magnification, but the focusing distance is pretty much zero. Anyway, that's what came out.
This is a maybug (or mayfly) which I shot using the same gear I just mentioned above. This one worked rather better, I think that's because I had better light and more room to move the tripod around.
If you've ever wondered what a broken bone looks like at the point of breakage....
No, this isn't a bone. Not quite. This is an antler which is a bony process to be found growing from the pedicles on the skulls of male deer. After the mating season, antlers fall off and regrow through the following year.
What you are looking at is the (more or less) flat surface where this antler was attached to the skull of its owner.
Raspberries have little hairs, right? You're looking at them. This is a raspberry blossom before the fruit ripens.
A fly, obviously.
These last two are rubbish, technically, but I added them here to show that, probably, your camera is only limited by your imagination. The first is the skin of kiwi fruit and the second, even worse but even smaller, is of the hairs on the leaves of an African Violet plant (Saintpaulia).
I know a guy who works for Leica. He tells me the set-up I use produces 25X magnification or maybe a little more, which is micro, rather than macro. If you fancy playing with micro you may need to combine two lenses, as I did, in which case you'll need a way of connecting the objectives face to face. I used a male-to-male ring which cost almost nothing from some guy on Ebay. The kit I used can be viewed on flickr, here.