There are lots of tiny little subjects and small details that can make interesting photographs, but sometimes you just can’t focus close enough with your standard lens to shoot them. The answer is to use a macro lens, close-up lens or extension tube.
A macro lens like the Sigma 105mm f/2.8 EX DG OS HSM Macro, which is available in a range of mounts and is specifically designed to allow you to focus closer than with a standard lens. In fact, a true macro lens lets you focus close enough to a subject to get life size, or 1:1 reproduction on your camera’s sensor. From the outside it looks just like a normal lens but the optical design enables closer focusing.
As you don’t get much depth of field when you’re focusing very close to a subject, most macro lenses are designed to give good performance at relatively small apertures and produce nice sharp details. They also tend to have good distortion control so that natural subjects look - well - natural.
Close-up filters screw onto your lens and allow you to focus much closer.
If you want to dip your toe into macro photography, a macro lens might seem like a big investment – but there is a more affordable alternative, a close-up lens. These lenses are often called close-up filters because they screw onto the end of your lens just like a filter. However, rather than changing the colour or exposure of an image, they allow you to focus more closely than you normally can with a standard lens.
Close-up filters come in a range of strengths and sizes and they’re very easy to use. Their impact depends upon the lens you attach them to – but you should find that you can focus much closer to the subject once one or more have been fitted. The results aren’t quite as good as you’ll get from a dedicated macro lens, but they’re a very useful and popular alternative.
Extension tubes can be used with a standard lens to turn it into a macro lens.
Extension tubes have no optics, but fit between your camera and lens to dramatically shorten the minimum focus distance and enable macro photography. They are often sold in sets of different lengths, or individually, and they can be used together or individually depending upon the extension that you require. The longer the extension, the closer you’ll be able to focus.
Extension tubes can be used with a standard lens to turn it into a macro lens, or used with a macro lens to get even closer to the subject and enable greater than life-size reproduction.
Modern extension tubes like the Kenko Teleplus DG tubes (available in a range of mounts) have electric contacts to enable autofocus, exposure metering and aperture control via the camera.