Macro is often used as a loose term to describe close-up photography. Technically speaking, a macro lens is one able to produce an object of actual size or greater on a camera's sensor, termed as a 1:1 or 1.0x macro lens.
However, many lenses not capable of this magnification are still labelled as macro lenses, while Nikon's micro classification adds to the terminology confusion.
A macro lens is designed to focus closer to the subject than a normal lens, with the likes of Canon's 60mm macro able to focus just 20cm from subject.
By moving the subject closer to the lens (or vice versa) the magnification is increased to enlarge a subject, but when shooting trickier subjects such as live bugs, a little more working distance may be required. In such situations the likes of Tokina's AT-X 100mm f/2.8 Macro is able to focus with 30cm between the subject and focal plane or Nikon's 200mm f/4 Micro can muster 50cm.
At full 1:1, a typical working distance is going to be less than 30cm from the end of the lens and the subject, which makes getting cracking shots all the trickier.
Intricate details are pronounced in macro shots, but the close-up nature of the subject means depth of field collapses into a very narrow window. You can forget about using super-wide apertures for macro shots.
Indeed many pros will stop right down to f/22 and add electronic macro flash to the front of the lens for increased shutter speed and, therefore, greater control.
Read our Best macro lens: 8 tested article
Typical macro lens examples
Nikon Nikkor 200mm f/4 AF Micro - £1,124
Olympus Zuiko Digital 35mm f/3.5 Macro Four Thirds - £210
Panasonic 45mm f/2.8 Macro Leica D Vario Elemar Micro Four Thirds - £600
Samsung NX 60mm f/2.8 ED OIS SSA Macro - £530
Sony E-mount (NEX) 30mm f/3.5 Macro - £230