The previous post showed how magnification changes with various lengths of extension tube, using a simple inexpensive fixed focal lens. Today, I want to show how changing other factors can affect your pictures, and for this I'm going to use a much more expensive lens, a 70-200mm telephoto lens.

Macro lenses are expensive. There is a cheap alternative, though, that can transform a regular lens into a macro lens: extension tubes. Extension tubes are simply hollow tubes that you put between the lens and the body of the camera. Optically inert, they shorten the focal distance and depth of field and bump up magnification, at the price of a loss of light.