Macro Photography

Taking close-up pictures of small things is called "macro photography.

What Kind of Camera

In the digital world, true macro photography is possible only with single-lens reflex cameras that take interchangeable lenses.

 

Macro Lenses

Dime at 1x magnification over a Dime at 5x magnification

Using a special-purpose lens called a macro lens, having a long barrel for close focusing. Some manufacturers call it a micro, which might actually be scientifically more accurate, but can be confusing, since it goes against the established convention. A macro lens might be optimized to provide its best performance at a magnification of 1:1. Some macro lenses, such as the Canon MP-E 65 mm f/2.8, can achieve higher magnification up to 5:1 macro, enabling photography of the structure of small insect eyes, snowflakes, and other minuscule but detailed objects. However, "standard" (1:1) macro lenses are more common.

There are different categories of macro lenses, depending on the focal length:

5060mm range typically used for product photography and small objects

90105mm range the standard focal range used for insects, flowers, small objects

150200mm range gives more working distance typically used for insects and other small animals
a few zooms provide a macro option, but they generally do not allow a 1:1 magnification

Placing an extension tube between the camera body and the lens. The tube has no glass in it; its sole purpose is to move the lens farther from the film or digital sensor. The farther the lens is from the film or sensor, the closer the focusing distance (and the greater the magnification) and the darker the image. Tubes of various lengths can be stacked together, allowing for increasing levels of magnification while simultaneously decreasing working distance. With tubes attached, the camera will lose the ability to focus to infinity.

Using a bellows attachment between the camera body and the lens to extend the lens to film plane distance. Similar to an extension tube, but adjustable.

Placing an auxiliary close-up lens in front of the camera's taking lens. Inexpensive screw-in or slip-on attachments provide close focusing at very low cost. The quality is variable, with some two-element versions being excellent while many inexpensive single element lenses exhibit chromatic aberration and reduced sharpness of the resulting image. This method works with cameras that have fixed lenses, and is commonly used with bridge cameras. These lenses add diopters to the optical power of the lens, decreasing the minimum focusing distance, and allowing the camera to get closer to the subject.


 

Focus

With a depth of field of around one millimeter for precise macro work, camera positioning and focus become critical. If you have a good tripod and head, you'll find that you have at least 10 controls to adjust. Each of them will move the camera. None of them will move the camera along the axis that you care about.

That's why people buy macro focusing rails. These are little rack and pinions capable of moving the entire camera/lens assembly forward and back. You use the tripod to roughly position the camera/lens and then the macro rail to do fine positioning.

 

Limited depth of field is an important consideration in macro photography. This makes it essential to focus critically on the most important part of the subject, as elements that are even a millimeter closer or farther from the focal plane might be noticeably blurry. Due to this, the use of a microscope stage is highly recommended for precise focus with large magnification such as photographing skin cells. Alternatively, more shots of the same subject can be made with slightly different focusing lengths and joined afterwards with specialized image editing software which picks out the sharpest parts of every image, artificially increasing depth of field.

Compact digital cameras and small-sensor bridge cameras have an incidental advantage in macro photography due to their inherently further working distance. For instance, some popular bridge cameras produce the equivalent magnification of a 420 mm lens on 35 mm format but only use a lens of actual focal length 89 mm (1/1.8″-type CCD) or 72 mm (1/2.5″-type CCD).

 Since depth of field appears to decrease with the actual focal length of the lens, not the equivalent focal length, these bridge cameras can achieve the magnification of a 420 mm lens with the greater depth of field of a much shorter lens. High-quality inexpensive auxiliary close-up lenses can be used to achieve the needed close focus; they function identically to reading glasses. This effect makes it possible to achieve very high quality macro photographs with relatively inexpensive equipment, since auxiliary close-up lenses are far cheaper than dedicated SLR macro lenses.
 

Lighting


The problem of sufficiently and evenly lighting the subject can be difficult to overcome. Some cameras can focus on subjects so close that they touch the front piece of glass in the lens. It is impossible to place a light between the camera and a subject that close, making this extreme close-up photography impractical. A normal-focal-length macro lens (50 mm on a 35 mm camera) can focus so close that lighting remains difficult. To avoid this problem, many photographers use telephoto macro lenses, typically with focal lengths from about 100 to 200 mm. These are popular as they permit sufficient distance for lighting between the camera and the subject.