A macro lens is a lens designed for taking extremely close-up photos of the subject. If you’ve ever seen a photo of a spider’s eyes or the veins of a leaf, that was a macro photo.
Most macro photos are taken with the camera within a foot or so of the subject. Non-macro lenses just won’t focus this close to the subject. Their Minimum Focus Distance (MFD) is normally around three feet. For a macro lens, the MFD is generally somewhere between 8 and 12 inches.
What really sets a macro lens apart isn’t just its close MFD, however—it’s the fact it combines a close MFD with a relatively long focal length. You can get your camera close to the subject and appear to zoom in close.
A perfect macro lens has an MFD and focal length that together allow you to get a 1:1 “reproduction ratio”. This means that the object you’re photographing is reproduced at exactly the same size it is in real life, on the camera sensor.
Let’s take a moment and think about this. If I take a portrait of someone so that their face covers the full image, then their roughly ten inch head is being reproduced at about one inch high on the camera sensor. That’s a reproduction ratio of 10:1. If I take a photo of a spiders’ head, however, I can have its quarter inch head reproduced at the exact same size. This is where the magnification comes from.
Macro photography doesn’t strictly have to have a reproduction ratio of 1:1. That only occurs when you’re using a good macro set up right at its MFD. In reality, you can get great looking macro photos even if the reproduction ration is 1:0.7 or even lower. Even 1:0.5 is going to be a lot closer than you’d be able to get with a regular lens.
If you’re interested in macro photography but are put off by the $900 price tag of something like a Canon 100mm f/2.8L Macro Lens, then there are other ways to take macro photos. You won’t have quite as much control as you get with a dedicated lens, but you can still take some stunning photos with some very simple equipment. Check out our guide to enjoying macro photography on the cheap for more.