Macro photography facts for kids

this spider is 3.9mm long.

Macro photography is a kind of photography. Macro photography is about photographing objects that are very close to the lens, the film or the sensor. Using the classic definition, in macro photography the image shown on the film plane (or sensor) is nearly as big as the object photographed. There are different ways to achieve this. The most common one is to use a specialised macro lens. Such lenses are good at focussing sharply on a small area approaching the size of the film frame. Most 35mm format macro lenses achieve at least 1:2, that is to say, the image on the film is half the size of the object being photographed. Many 35mm macro lenses are 1:1, meaning the image on the 135 film is the same size as the object being photographed. Another important difference is that lenses designed for macro are usually at their sharpest at macro focus distances and are not quite as sharp at other focus distances.

In recent years, the term macro has been used in marketing material to mean being able to focus on a subject close enough so that when a regular 6×4 inch (15×10 cm) print is made, the image is life-size or larger. With 35mm film this requires a magnification ratio of only approximately 1:4, which demands less of lens quality than 1:1. With digital cameras the actual image size is rarely stated, so that the magnification ratio is largely irrelevant; cameras instead advertise their closest focusing distance.

Typical subjects are still life, such as fruit, flowers, jewelry and small household objects. Macro photography often reveals details of the subject not visible with the naked eye.

Different ways to do macro photography

• Using a specialised macro lens. These exist in different focal length, from what should be a normal lens (40-60mm for 35mm flim), to medium to long telephotos (around 100mm, and 180-200mm). Very often they offer reproduction ratios of 1:2, or 1:1.
• Sometimes ordinary lenses have a macro position. They usually offer reproduction ratios around 1:4.
• Using what are called extension tubes. These are small inserts between the lens and the camera. They move the lens farther away from the camera, increasing reproduction ratio, decreasing depth of field. The main problem with that is that they cost light, usually cutting brightness by a factor between two and four. It may also be impossible to get a sharp view of the object photographed, if it is farther away. An extension tube where the distance can be changed continuously is called bellows.
• Using a close-up lens, in front of the lens. This will act like a magnifying glass
• Using a telephoto extender. This will change the focal length of the lens, and give a bigger image.

Problems with macro photography

There are two main problems with macro photography:

• The Depth of field can be extremely shallow. This means that objects that are even a millimetre closer of farther away can be out of focus - blurry.
• Getting enough light: The more magnified an image is, the more difficult it is to get enough light. There are also special flashes, called ring flashes. These are mounted on the lens. Another option is to use a telephoto macro lens (which is more expensive). This means working distance is increased.

Images for kids

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  Macro photograph of a common yellow dung fly (Scathophaga stercoraria) made using a lens at its maximum 1:1 reproduction ratio, and an 18×24mm image sensor, the on-screen display of the photograph results in a greater than life-size image.

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  Headshot of a dragonfly taken with a 100 mm macro lens coupled with a 50 mm lens in reverse at the end.

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  Macro photograph of an ant

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  Macro photograph of a fern sorus using 4:3 aspect ratio

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  Canon MP-E 65 mm macro lens. Small front lens elements are typical of macro lenses.

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  Extension tubes for extreme macro use with SLRs. Note the pen placed through the tube to illustrate that it does not contain any lens elements.

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  Bellows fitted between an SLR and reversed lens

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  Typical close-up lens

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  Wide-angle lens used as a reversed lens in front of a macro lens

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  Minolta 100-300mm zoom lens with markings for reproduction ratio

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  35 mm equivalent magnification: The photograph on top was taken with a full-frame (35 mm) sensor digital SLR camera and a 100 mm macro lens at 1:1 magnification. The photograph on the bottom was taken with a Micro Four Thirds (2x crop) sensor camera and a 50 mm macro lens at 1:2 magnification. The subject height in both images is 24 mm. Photographs taken with these two set-ups will be at practically the same scale at the same print size, lending the photograph on the bottom its 1:1 35 mm equivalent reproduction ratio status.

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  35 mm equivalent reproduction ratio: the photograph on the left was taken with a Micro Four Thirds (2x crop) sensor camera and a 50 mm macro lens at 1:2 magnification. The photograph on the right was taken with a full-frame (35 mm) sensor digital SLR camera and a 100 mm macro lens at 1:1 magnification. The photographs are practically indistinguishable and therefore equivalent. As the images were taken at slightly different angles, the two images can be viewed as a cross-eyed stereogram.

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  Housefly on a leaf photographed with a shallow depth of field, noticeable in the blurring in the foreground and the fly's right wing

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  Optical scheme of close-up macro photography

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  Reversed-lens macro photography optical scheme

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  Optical scheme of macro photography using reversed lens and telephoto lens

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  Optical scheme of macro photography using extension tube

See also

In Spanish: Macrofotografía para niños