A macro lens is one that is designed with optics inside the lens to perform close-up photography. Most lens producers have at least one macro lens in their lens offerings.
There are different types of macro lenses. Some zoom lenses are qualified as macro lenses. A commonly purchased lens in the zoom category is the Tamron 70-300mm macro lens. It is a fairly inexpensive lens that is unique in that it can produce macro-type photos because of the optical design of the lens.
The reason that macro lenses are well-suited for close-up photography is that the optics of the lenses are such that they do not create the optical distortion that is common in non-macro lenses at close range. Even though you can use some lenses for closer focus, there is a perspective distortion that has to be addressed in post editing software such as photoshop in order to get the pictures looking natural. This is not the case with a good macro lens.
Most Popular Macro Lenses
The most popular macro lenses are in the 100mm range. These are prime lenses, meaning that they have a single focal length. It is easier to produce a quality lens that takes excellent close-up photos when a single focal length is used.
Canon's best selling macro lens is the Canon EF 100mm macro lens, the most popular one that Nikon makes is their 105mm Micro lens (Nikon uses the term micro in place of macro).
In addition to OEM lenses (these are the ones made by the camera brand) there are some very good third party macro lenses. Two excellent choices are the Sigma 105mm macro lens and the Tamron AF 90mm macro lens. Both of these lenses are made for the most popular digital SLR brands, including Canon, Nikon, Sigma, Sony, Olympus, and Pentax. They have gotten consistently high ratings by those who have purchased them over the years. Plus, you can save some money when purchasing these off-brand lenses. This is one area where third party companies have really done a good job in making superior products that rival those of the brand-name companies.
Other focal length lenses are also well regarded in the macro lens category. On the short end, there are lenses in the 50mm or 60mm range that do very well. Then there are some 150mm lenses that are popular for doing even closer photography.
Macro Lenses for Telephoto Photography
One of the great features of modern macro lenses is that they almost all have the ability to focus to infinity. This means that they can be used for other types of photography such as landscapes, street shots, and anything that might require a medium telephoto lens. But, perhaps the most popular use is for portraits. Macro lenses are especially suited for getting those blurry backgrounds that are so highly desired in portrait photography.
Your macro lens will more than likely have another added bonus. The lenses listed above have a very wide aperture, usually f/2.8 or wider. This makes them excellent candidates for low-light photography. For instance, you can use your macro lens for the next music concert where the lighting is a problem for most normal lenses.
Macro lenses are very versatile. One of them should find its way into your camera bag soon. But if you already have a macro lens, consider using it for some of the other types of photography you do in addition to the close-up shots.