Above answers are correct, as far as they go... It's true, DSLRs do not have a "macro mode", like some (many?) point and shoot cameras do.
One way to "do macro" with a DSLR is to buy a true macro lens. This might be the easiest and best quality way, in fact. But, of course, there's the expense of buying a macro lens. Still, Canon's EF-S 60/2.8 USM is excellent and is one of the more affordable. I like a little longer focal length and use an EF 100/2.8 USM instead, though it costs a bit more. There are many other excellent macro lenses.
If you got a kit lens with the camera, it might be able to at least do close ups. You'll have to look up the specs for your particular lens, but some can do 021X or even 0.3X magnification, which are around 1/5 life size to about 1/3 life size... not really "macro" per se, more like "close-up".
You also can make a lens you already have closer focusing/higher magnification with some simple accessories. One way is to add a macro extension tube between the lens and the camera. A good quality set of Kenko macro extension tubes includes 12mm, 20mm and 36mm tubes and is currently selling for $109, while a bit more plasticky set from Vello costs $79. There are some cheaper... even some under $15 for a set, but steer clear of those. They don't have the electronic contacts to allow your lens to focus and to control the lens aperture (f-stop setting).
Another way to make a lens you already have focus closer is to add a close-up lens or "diopter" to it. This attaches just like a filter, but optically increases the lens' degree of magnification. Canon makes two high quality, two-element close-up lenses: 250D and 500D. These come in various diameters, depending upon what size filter threads the lens has. The 250D is the stronger of the two and is recommended for use with lenses of 30mm to 135mm focal length. The 500D is recommended for use with 70mm to 300mm focal lengths. Canon also makes a less expensive "500" that is single element. Personally I think close-up lenses such as these work best with prime lenses, instead of zooms, too.
I shoot a lot of macro and use all the above: true macro lenses, macro extension rings, and close-up lenses. Most of the time I just use a macro lens, for highest quality images, speed, convenience and versatility. But I don't always have a macro lens with me, so I always keep some macro extension rings in my camera bag, since they can turn practically any lens into a macro or at least near-macro lens. Close-up lenses/diopters are ratther specialized, since it's necessary to buy them to fit particular lenses. I have a 500D in 77mm size that I sometimes use on a 300mm lens, or more occasionally a 70-200mm zoom.
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Alan Myers
San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7D(x2), 50D(x3), some other cameras, various lenses & accessories
FLICKR & EXPOSUREMANAGER
