Close-up and Macro Photography (Part II)

Continued from last month

- Ashok Kandimalla

Stacked lenses:

The principle of using a supplementary lens can be extended by replacing it with another photographic lens which is called the secondary lens (Picture 1). Note that the primary and secondary lenses are mounted front to front. This is done with the help of a macro coupler (also called a male-to-male coupler). This is just a ring with male threads on both sides. With this, you can reverse the secondary lens and fix it to the primary lens which in turn is fixed to the camera. This will allow the secondary lens to be reversed and mounted on the primary lens. You may notice vignetting (darkening of corners) when using stacked lenses (Picture 2), so look out for them and compose accordingly.

Stacked lenses work best with primary lenses of focal lengths between 100 to 200 mm and secondary lenses with focal lengths around 50 mm. The formula for magnification is the same as when you use a supplementary lens. So, if you are using a primary lens of 200 mm and a secondary lens of 50 mm lens you will get a magnification of 4X.

Another interesting fact is that you are mounting the secondary lens to the front of your primary lens and not to your camera body. Hence, the secondary lens need not be compatible with your camera at all. You can, for example, use a Nikon camera with a Nikon primary lens and a Canon (or any other manufacturer's) lens as the secondary lens.

Tip: Always keep the aperture fully open on the stacked lens for the brightest viewing. Also, remember that exposure is controlled only by the aperture of the primary lens.