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It’s easy to get confused over some of the terms applied to macrophotography. Even the name itself is sometimes misunderstood. Macrophotography is not microphotography, which involves microfilm and other miniature images; nor is it photomicrography, which is taking pictures through a microscope. Nor, necessarily, is it close-up photography, which, strictly speaking, applies to a tight shot in cinematography. Macrophotography is generally the production of closeup photos, usually taken from a foot away or less. Because the terms macrophotography and close-up photography are nevertheless used interchangeably these days, I’ll do so in this blog. There are several other terms that cause confusion:

Magnification. In macrophotography, the amount of magnification is usually more important than how close you can get to your subject. For example, if you’re photographing a coin and want it to fill the frame, it makes little difference whether you shoot the coin using a 50mm lens from 4 inches away or with a 100mm lens from 8 inches away. Either one will produce the same magnification. Because of this, close-up images and the macro capabilities of cameras and lenses are usually described in terms of their magnification factor, rather than the camera/subject distance. Moderate close-ups may involve 1:4 or 1:3 magnifications. Larger-than-life-size images may involve 2:1 or 4:1 (or 2X or 4X) magnifications. The small stone carving in Figure 7.2 was photographed at approximately a 1:4 ratio.

Perspective. Subject distance does make a difference in terms of perspective, however. Although the same size image can be taken from farther away or closer to produce the same magnification, the apparent perspective of the image will change. Objects in a scene that are significantly closer to the lens than other objects will look larger and out of proportion. I’ll address this aspect in more detail later.

Backfocus. This is the tendency of some autofocus systems to focus behind the intended subject rather than spot on it. (Frontfocus errors also exist, but they are less common.) The phenomenon is not limited to macrophotography, but does tend to be more obvious in close-up shots. You can diagnose this problem by laying out a tape measure, photographing it on a slant with focus set on some mid-point, and then seeing if the point of focus is where it should be. Frequently, backfocus problems can be fixed by the camera’s vendor.

Depth-of-field/depth-of-focus. Depth-of-field is the range of a subject that appears acceptably sharp at a particular lens opening. Changing to a smaller f-stop increases depthof-field, while opening up a lens reduces it. Wide-angle lenses have more depth-of-field than telephoto lenses at the same magnification. Depth-of-focus is the amount you can increase the distance between the imaging sensor or film and the subject and still retain sharpness. Although often confused with depth-of-field, this term is most often applied to “fixed” setups where the sensor/film or flat subject is moveable, such as photoreproduction cameras or scanners.