Macro photography is
close-upIn film, television, still photography and the comic strip medium a close-up tightly frames a person or an object. Close-ups are one of the standard shots used regularly with medium shots and long shots. Close-ups display the most detail, but they do not include the broader scene...
photographyPhotography is the process, activity and art of creating still or moving pictures by recording radiation on a sensitive medium, such as a photographic film, or an electronic sensor...
. The classical definition is that the
imageAn image is an artifact, for example a two-dimensional picture, that has a similar appearance to some subject—usually a physical object or a person....
projected on the "film plane" (i.e.,
filmPhotographic film is a sheet of plastic coated with an emulsion containing light-sensitive silver halide salts with variable crystal sizes that determine the sensitivity, contrast and resolution of the film...
or a digital sensor) is close to the same size as the subject. On
35 mm filmThe term 135 was introduced by Kodak in 1934 as a designation for cartridge film wide, specifically for still photography. It quickly grew in popularity, surpassing 120 film by the late 1960s to become the most popular photographic film format...
(for example), the
lensA photographic lens is an optical lens or assembly of lenses used in conjunction with a camera body and mechanism to make images of objects either on photographic film or on other media capable of storing an image chemically or electronically.While in principle a simple convex lens will suffice,...
is typically optimized to focus 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 1/2 the size of the object being photographed.
Macro photography is
close-upIn film, television, still photography and the comic strip medium a close-up tightly frames a person or an object. Close-ups are one of the standard shots used regularly with medium shots and long shots. Close-ups display the most detail, but they do not include the broader scene...
photographyPhotography is the process, activity and art of creating still or moving pictures by recording radiation on a sensitive medium, such as a photographic film, or an electronic sensor...
. The classical definition is that the
imageAn image is an artifact, for example a two-dimensional picture, that has a similar appearance to some subject—usually a physical object or a person....
projected on the "film plane" (i.e.,
filmPhotographic film is a sheet of plastic coated with an emulsion containing light-sensitive silver halide salts with variable crystal sizes that determine the sensitivity, contrast and resolution of the film...
or a digital sensor) is close to the same size as the subject. On
35 mm filmThe term 135 was introduced by Kodak in 1934 as a designation for cartridge film wide, specifically for still photography. It quickly grew in popularity, surpassing 120 film by the late 1960s to become the most popular photographic film format...
(for example), the
lensA photographic lens is an optical lens or assembly of lenses used in conjunction with a camera body and mechanism to make images of objects either on photographic film or on other media capable of storing an image chemically or electronically.While in principle a simple convex lens will suffice,...
is typically optimized to focus 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 1/2 the size of the object being photographed. Many 35mm macro lenses are 1:1, meaning the image on the film is the same size as the object being photographed. Another important distinction 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
inchAn inch is the name of a unit of length in a number of different systems, including Imperial units, and United States customary units. There are 36 inches in a yard and 12 inches in a foot...
(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.
Macrosocopy competes with the
digital microscope,A digital microscope is a variation of a traditional optical microscope that uses optics and a charge-coupled device camera to output a digital image to a monitor. A digital microscope differs from an optical microscope in that there is no provision to observe the sample directly through an...
where a small camera tube can be attached directly to a computer, usually by a USB port. Macroscopy also competes with photomicroscopy, and it is much less expensive to achieve high quality images. However, high magnification images are more difficult using macroscopy.
The method is especially useful in forensic work, where small details at crime or accident scenes may often be significant.
Trace evidenceTrace evidence is normally caused by objects or substances contacting one another, and leaving a minute sample on the contact surfaces. Material is often transferred by heat induced by contact friction....
such as fingerprints and
skid markIn motoring terms, a skid mark is the mark a tire makes when a vehicle wheel stops rolling and slides or spins on the surface of the road. More generally, any solid which moves against another can cause visible marks, and is an important aspect of trace evidence analysis in forensic science and...
s is especially important, and easily recorded using macroscopy.
FractureA fracture is the separation of an object or material into two, or more, pieces under the action of stress.The word fracture is often applied to bones of living creatures, or to crystals or crystalline materials, such as gemstones or metal. Sometimes, in crystalline materials, individual crystals...
surfaces from broken products are very revealing using
fractographyFractography is the study of fracture surfaces of materials. Fractographic methods are routinely used to determine the cause of failure in engineering structures, especially in product failure and the practice of forensic engineering or failure analysis...
, especially when photographed using glancing light to highlight surface details.
Equipment
Techniques for making a well-lit image of the required size include:
- Using a lens specifically designed for close work and with a long barrel for close focusing, called a macro lens. 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
The MP-E 65mm Macro f/2.8 is a photographic lens manufactured by Canon for use on the EOS photographic system. It is a manual focus lens for the EF mount....
, 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 lengthThe focal length of an optical system is a measure of how strongly it converges or diverges light. For an optical system in air, it is the distance over which initially collimated rays are brought to a focus...
:
- 50–60mm range typically used for product photography and small objects
- 90–105mm range the standard focal range used for insects, flowers, small objects
- 150–200mm 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
- Extending the distance between the lens and the film or sensor by inserting either extension tube
An extension tube is an accessory for cameras with interchangeable lenses, used primarily for macro photography. The tube contains no optical elements; its sole purpose is to move the lens farther from the image plane. The farther away the lens is, the closer the focus, the greater the...
s or a continuously adjustable bellows, with no optical components; between the camera body and the lens. The further the lens is from the film or sensor, the closer the focusing distance, the greater the magnification, and the darker the image for the same aperture. Tubes of various lengths can be stacked, decreasing lens-to-subject distance and increasing magnification. Bellows or tubes must be removed for normal working at longer distances. They can be used in conjunction with some other techniques (e.g., reversing the lens).
- Placing an auxiliary close-up lens
In photography, a close-up filter, close-up lens or macro filter is a simple secondary lens used to enable macro photography without requiring a specialised primary 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 aberrationIn optics, chromatic aberration is the failure of a lens to focus all colors to the same point. It occurs because lenses have a different refractive index for different wavelengths of light...
and reduced sharpnessIn photography, acutance is the edge contrast of an image. Acutance is related to the amplitude of the derivative of brightness with respect to space. Due to the nature of the human visual system, an image with higher acutance appears sharper even though an increase in acutance does not increase...
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.
- Attaching a telephoto extender between the camera body and the lens. A 1.4× or 2× teleconverter
A teleconverter is a secondary lens which is mounted between the camera and a photographic lens. Its job is to enlarge the central part of an image obtained by the objective lens. For example, a 2× teleconverter enlarges the central 12×18 mm part of an image to the size of...
gives a larger image, adding macro capabilities. As with an extension tube, less light will reach the film or sensor, and a longer exposure time will be needed. However, working distance remains the same as without the teleconverter.
- Reversing the lens using a "reversing ring". This special adapter attaches to the filter
In photography, a filter is a camera accessory consisting of an optical filter that can be inserted in the optical path. The filter can be a square or oblong shape mounted in a holder accessory, or, more commonly, a glass or plastic disk with a metal or plastic ring frame, which can be screwed...
thread on the front of a lens and makes it possible to attach the lens in reverse. Excellent quality results up to 4x lifesize magnification using fairly cheap, "standard" (not specially designed for macro) lenses can be produced. For cameras with all-electronic communications between the lens and the camera body, such as Canon EOS, reversing rings are available which allow all camera functions, including open aperture metering, to be used. When used with extension tubes or bellows a relatively cheap but highly versatile macro system can be assembled.
- Reversing a lens of lesser focal length in front of a normally mounted lens using an inexpensive macro coupler, which screws into the filter threads on the front of the two lenses to join them mechanically. This method allows most cameras to maintain the full function of electronic communication with the normally mounted lens for features such as open-aperture metering. Magnification ratio is calculated by dividing the focal length of the normally mounted lens by the focal length of the reversed lens (e.g., when an 18 mm lens is reverse mounted on a 300 mm lens the magnification ratio is 16:1). The use of automatic focus is not advisable as the extra weight of the reverse-mounted lens could damage the autofocus mechanism. Working distance is significantly less than the original lens.
- Depth of field
In optics, particularly as relates to film and photography, the depth of field is the portion of a scene that appears acceptably sharp in the image...
is extremely small when focusing on close objects; a small stopIn optics, the f-number of an optical system expresses the diameter of the entrance pupil in terms of the focal length of the lens; in simpler terms, the f-number is the focal length divided by the "effective" aperture diameter...
is often required to ensure sufficient depth of field. This requires either a slow shutter speed or bright lighting for correct exposure; in all but the brightest natural lighting if a prolonged exposure is not advisable, auxiliary lighting (such as from a flash unitA flash is a device used in photography that produces an instantaneous flash of artificial light at a color temperature of about 5500 K to help illuminate a scene...
) is required. Uniform lighting can be difficult with subjects very close to the lens; a ring flashA ring flash, invented by Lester A. Dine, in 1952 originally for use in dental photography, is a circular photographic flash that fits around the lens, especially for use in macro photography...
mounted on the front of the lens can provide even illumination. Good results can also be obtained by using a flash diffuser, which can be made of inexpensive StyrofoamStyrofoam is a trademark of Dow Chemical Company for presently made for thermal insulation and craft applications..In 1941, researchers in Dow's Chemical Physics Lab found a way to make foamed polystyrene...
.
Depth of field
Limited
depth of fieldIn optics, particularly as relates to film and photography, the depth of field is the portion of a scene that appears acceptably sharp in the image...
is an important consideration in macro photography. This makes it essential to
focusIn geometrical optics, a focus, also called an image point, is the point where light rays originating from a point on the object converge. Although the focus is conceptually a point, physically the focus has a spatial extent, called the blur circle. This non-ideal focusing may be caused by...
critically on the most important part of the subject, as elements that are even a
millimetreThe millimetre is a unit of length in the metric system, equal to one thousandth of a metre, which is the current SI base unit of length.Equal to 1000 micrometres.Equal to 1000000 nanometres....
closer or farther from the focal plane might be noticeably blurred. 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 higher working distance. For instance, some popular bridge cameras produce the equivalent magnification of a 420 mm lens on
35 mm format35 mm film is the basic film gauge most commonly used for both still photography and motion pictures, and remains relatively unchanged since its introduction in 1892 by William Dickson and Thomas Edison, using film stock supplied by George Eastman. The photographic film is cut into strips...
but only use a lens of actual focal length 89 mm (1/1.8″-type
CCDA charge-coupled device is a device for the movement of electrical charge, usually from within the device to an area where the charge can be manipulated, for example conversion into a digital value. This is achieved by "shifting" the signals between stages within the device one at a time...
) or 72 mm (1/2.5″-type CCD). (See
crop factorIn digital photography, a crop factor is related to the ratio of the dimensions of a camera's imaging area compared to a reference format; most often, this term is applied to digital cameras, relative to 35 mm film format as a standard. In the case of digital cameras, the imaging device would be a...
.) 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 fieldIn optics, particularly as relates to film and photography, the depth of field is the portion of a scene that appears acceptably sharp in the image...
of a much shorter lens. High-quality 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 macrophotographs with relatively inexpensive equipment, since auxiliary closeup lenses are 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 of the lens. It is impossible to place a light between the camera and a subject that close, making 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
telephotoIn photography and cinematography, a telephoto lens is a specific construction of a long focal length photographic lens in which the physical length of the lens is shorter than the focal length. In these lenses the optical centre lies outside of its physical construction, such that the entire lens...
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.
Ring flashA ring flash, invented by Lester A. Dine, in 1952 originally for use in dental photography, is a circular photographic flash that fits around the lens, especially for use in macro photography...
es, with flash tubes arranged in a circle around the front of the lens, can be helpful in lighting at close distances. Ring lights have emerged, using white
LEDsA light-emitting diode , is an electronic light source. The first LED was built in the 1920s by Oleg Vladimirovich Losev, a radio technician who noticed that diodes used in radio receivers emitted light when current was passed through them...
to provide a continuous light source for macrophotography.
Homemade flash diffusers made out of white Styrofoam or plastic attached to a camera's built-in flash can also yield surprisingly good results by diffusing and softening the light, eliminating
specular reflectionSpecular reflection is the mirror-like reflection of light from a surface, in which light from a single incoming direction is reflected into a single outgoing direction...
s and providing more even lighting.
See also
- Digital microscope
,A digital microscope is a variation of a traditional optical microscope that uses optics and a charge-coupled device camera to output a digital image to a monitor. A digital microscope differs from an optical microscope in that there is no provision to observe the sample directly through an...
- Wildlife photography
Wildlife photography is the act of taking photographs of wildlife.Wildlife photography is regarded as being one of the more challenging forms of photography. As well as needing sound technical skills, such as being able to expose correctly, wildlife photographers generally need good field craft...
- Nature photography
Nature photography refers to a wide range of photography taken outdoors and devoted to displaying natural elements such as landscapes , wildlife, plants, and close-ups of natural scenes and textures...
- Cloudscape photography
- Landscape art
Landscape art depicts scenery such as mountains, valleys, trees, rivers, and forests. Sky is almost always included in the view, and weather usually is an element of the composition....
- Photographs
- Photomicroscopy
- Forensic Science
- Forensic engineering
Forensic engineering is the investigation of materials, products, structures or components that fail or do not operate/function as intended, causing personal injury or damage to property. The consequences of failure are dealt with by the law of product liability. The field also deals with retracing...
- Forensic materials engineering
A branch of Forensic engineering, the subject focuses on the material evidence from crime or accident scenes, seeking defects in those materials which might explain why an accident occurred, or the source of a specific material to identify a criminal...
- Forensic photography
Forensic photography is the art of producing an accurate reproduction of a crime scene or an accident scene for the benefit of a court or to aid in the investigation. It is part of the process of evidence collecting. It provides investigators with photos of bodies, places and items involved in the...
- Forensic polymer engineering
The study of failure in polymeric products is called forensic polymer engineering. The topic includes the fracture of plastic products, or any other reason why such a product fails in service, or fails to meet its specification...
External links