Canon Macro Lenses »
About Canon Macro Lenses
The essential difference between a macro lens and an ordinary lens is that the optical elements of a macro lens can move over a greater range. This allows them to bring subjects at a closer distance into sharp focus. The EF100mm f2 USM and the EF100mm f2.8 Macro USM have the same focal lengths (100mm), but the Macro lens can focus as close sharply on a subject as close as 31cm, while the close focus distance for the non-macro lens is 90cm. Being able to focus closer, the macro lens magnifies an image more. A true macro lens is one that can create a life-size image – 1:1 magnification or greater.
Traditional lens design uses a ‘focusing lens group’ to focus the lens. This usually comprises either the front lens element, or group of elements, or all of the lens elements, that move forwards and backwards to produce a sharp image. However, this can affect optical performance, particularly at close focusing distances. The more recent lenses, however, have been given a USM tag to signify the inclusion of an UltraSonic Motor. This is the high-speed motor that drives the autofocus, enabling the lens to focus quickly and quietly. The new macro lens also uses an inner focusing system, which moves one of the internal optical groups to achieve focus, as opposed to moving the larger front lens element group forward as in the case of the older Canon macro lenses.
Not only is the internal optical group lighter, and therefore easier for the USM motor to move, but it also allows a closer minimum focusing distance. The new lens itself does not change length as you focus. This means that handling and balance is not affected when you focus, that you won’t hit your subject unintentionally in a super close focus situation and that the lens is also less likely to cast its own shadow over the subject. Macro lenses are not just for macro photography. Most of them focus to infinity as well, making them exceptionally versatile lenses. Canon offers a range of prime macro lenses with focal lengths from 50mm to 180mm. Most take you up to life-size magnification while one starts at life-size, rising to five times life-size magnification.