1. Supplementary lenses.

These are simple [one or two-element] magnifying lenses that can be added to the main lens where a filter normally fits; they can be used in conjunction with other devices e.g. extension tubes. Their degree of magnification is quoted in ‘diopters’ – e.g. +2; +3; +4.

2. Dedicated macro lenses.

These are lenses specifically designed to work at close distances; usually a ‘prime’ lens [i.e. non-zoom] and typically about 90mm to 110mm focal length. A macro lens can be used for more general applications – e.g. they make good portrait lenses.

3. Zoom lenses with a macro facility.

These are like a normal zoom lens but at anything less than full zoom will focus only down to about 24 inches When set to full zoom a new part of the focus scale opens up allowing focus down to about 12 inches.

4. Extension tubes.

Extension tubes fit between the camera body and whatever lens you are using. They have no lenses themselves and their only function is to take the lens farther away from the film or sensor than the camera’s normal focussing mechanism allows. Usually they are available in sets in a range of sizes from about 5mm up to 50mm. They can be screwed together to add to the degree of extension.

5. Reversed lenses.

Using an adaptor it is possible to turn your normal 50mm lens ‘back-to-front’. In its normal position the lens is designed on the assumption that the distance between the film and the back of the lens will be a mere fraction of the distance between the lens and the subject being photographed. In macro photography those two distances come nearer to being equal and the lens gives better performance when reversed.

6. Stacked lenses.

It is possible to use a standard lens as a ‘supplementary’ lens to another main lens. Typically a standard 50mm prime lens is reversed and ‘stacked’ on the front end of a zoom lens using a screw adaptor. The aperture of the 50mm lens is left wide open and – in effect – becomes just a very sophisticated supplementary lens giving extra magnification with much better performance then a simple single or double-element supplementary lens.