I’ve seen some great macro photos, and want to try it for myself, do I have to use a macro lens?
John Gowring, Dacorum
BRIAN SAYS… Macro photography technically starts when the image on your sensor is the same size as the subject. This is called life-size or 1:1 reproduction. Only macro lenses offer this level of magnification. For many subjects, a lesser magnification is still useful, especially when viewing a cropped part of the shot, or on a larger display or print.
Some non-macro lenses have good capabilities for close-up shots, if not true macro. The EF 24-70mm f/4l IS USM, for example, has a close-up capability that captures images of subjects at 0.7x their original size. Telephoto lenses have reasonable magnification, but limited close-focus capability. Adding an extension tube spaces the lens further from the sensor allowing focus on closer subjects. A 70-200mm or 55-250mm lens with a 25mm extension tube is a good example.
You can also use close-up lenses that fit on the front of your lens like a filter. They work a little like a magnifying glass, boosting the size of the subject.
Macro lenses offer at least 1:1 magnification, but choose longer focal length models to increase the working distance. Canon macro lenses are the EF-S 60mm f/2.8 Macro USM, several EF 100mm f/2.8 Macro models and the EF 180mm f/3.5l Macro USM. Working distance for life-size images is 20cm for the 60mm lens, 30cm for the 100mm lenses and 48cm for the 180mm lens. Longer working distance is helpful for insect photography, and for increased depth of field. Remember that the distance is measured from the sensor plane, and not from the front of the lens element itself.