A Guide to Lens Buying

If you are serious about this genre, there is only one type of lens to buy - a dedicated macro lens.

- Ashok Kandimalla

Macro

Internally a macro lens has a modified focusing mechanism (called a helical) to help some lens elements move farther than the usual designs thus giving close focusing abilities. Many zooms claim to have 'macro' capability but that is more due to marketing departments' description rather than true optical performance. Even if the lens focuses close to 1:3 or even 1:2, it cannot be termed as a macro lens as lenses dedicated to this purpose have flat field performance and are corrected for image capture at very short subject distances (Picture 2).

Macro lenses are available in focal lengths starting from around 50 mm and going up to 200 mm. Short focal length macro lenses are meant for copying work and are not good for general purpose work. Longer focal length macro lenses give the same magnification at a greater subject to camera distance. For example, a 200 mm lens will give a greater working distance than a 50 mm lens for the same magnification. This can be useful in nature photography. After all, you would not want to photograph a scorpion from 2 inches!

In the recent past many manual focus (MF) macro lenses have appeared and some of these go even beyond the normal 1:1 magnification. You can consider these if such magnification is needed for your work.