3.1 Macro Lenses
Description
This article is from the Gross
Specimen Photography, by Ed Uthman, MD
3.1 Macro Lenses
Operationally, the only thing special about these is that they have an extra long focusing extension to allow you to focus on very close objects. They are generally available in the "normal" focal length and the medium telephoto ranges. For instance, Nikon makes two excellent macros, a 60 mm and a 105 mm. Since they are aimed at the technical market, macro lenses tend to have excellent optics, are very durable, and are several times more expensive than normal lenses of corresponding focal lengths. Most macros in the normal lens category allow you to focus down to objects close enough to give you a "3:1" or "2:1" ratio; that is, the image size is one- third or one-half, respectively, the size of the subject. Most macro lenses can be used with an inexpensive extension ring, which allows focusing down to 1:1 or "life size," i.e., the image size is the same as the subject size (Sigma makes a very nice, not-too-expensive macro lens that focuses down to 1:1 without an extension ring, and Nikon's much pricier 105 mm AF macro lens allows a 1:1 focus). This allows you to take some breathtaking shots of otherwise unimpressive subjects, such as pituitary adenomas. You can even make a corpus luteum look spectacular.
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