Practical Artistry: Light & Exposure for Digital Photographers

76 Working with Aperture

Macro Photography and Aperture

Macro Photography and Aperture

Some people use the phrase macro photography to ap-

ply to any close-up work. A more stringent definition

is that macro photography is the creation of close im-

a

ges in which the physical size of the capture is greater

than the size of the object being photographed. For ex-

a

mple, if a coin with a one-inch diameter is captured

by your sensor so that the pixels making up the coin

measure an inch in diameter, that is called a 1:1 cap

-

t

ure. If the pixels on the sensor made up a ratio of 1.5:1

compared to the subject, then the size of the capture is

said to be greater than life.

How Do Extension Devices Work?

The best macro gear for dSLRs works by adding space between

the lens and the camera. This is how extension tubes, bellows,

and (in combination with special optics) macro lenses work.

The added space increases the focal length of the lens

combined with the extension device. (See “Understanding

f-Numbers and f-Stops” on page 52 for a dention of focal

length.)

Since f-numbers are dened in terms of the ratio of eective

focal length to the diameter of the aperture, in some cases very

small f-stops result, like f/36, f/40, or even f/64, which may be

smaller than the hardware rating for minimum f-stop of the

lens without the extension device.

77

Working with Aperture

This is an extreme macro photo of a ...