In photographic terms, “macro” means the optical ability to produce a 1:1 or higher magnification of an object on the sensor. For instance if you photograph a aquarium shrimp with an actual size of 21.6 mm so that it fills the 35mm sensor (43.3mm diagonal), the shrimp gets magnified with a ratio of 43.3 to 21.6 or 2:1, or with a magnification of 2X. Macro photography typically deals with magnifications between 1:1 and 50:1 (1X to 50X), while close up photography ranges from 1:1 to 1:10 (1X to 1/10X).

Macro photography

Macro photography (click to enlarge)

From the above it is easy to understand that digital cameras with sensors smaller than 35mm film have better macro capabilities. Indeed, a digital compact camera with a focal length multiplier of 4X can capture the above shrimp of 21.6mm length with a magnification of only 1:2 (close-up) instead of the 2:1 (macro) required with the 35mm camera. In other words, macro results are achieved with (easier) close-up photography.

On digital cameras there is often a Macro Focus mode which switches the auto focus system to attempt to focus on subjects much closer to the lens.

We measure macro ability (of cameras with non-interchangeable lenses) as the ability of the lens to get the best possible frame coverage. So a camera which can fill the frame with a subject that is 20mm wide has better macro capabilities than one which can only capture a 40mm wide subject.

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