Macro photography

Compare macrographs, photomicrographs, and microphotographs.

Macro photography, also called photomacrography^[1][2] or macrography,^[3] and sometimes macrophotography,^[4][a] is extreme close-up photography in which the subject is reproduced at greater than its actual size.^[3][6] Macro photographs usually feature very small subjects and living organisms like insects.

A dedicated macro lens, such as the Vivitar Series 1 90 mm f/2.5 shown here, is one of multiple methods to achieve the large reproduction ratio required for photomacrography.

Definitions

The reproduction ratio or magnification is the subject size captured on the film frame (or image sensor) compared to the actual subject size.^[7]: 29 In the strictest definition, a macro photograph is one in which the size of the image captured is life-size or larger compared to the original subject.^[8]

Minolta Zoom-Rokkor 100–300mm lens with markings for reproduction ratio

Building on this, a macro lens is therefore a lens capable of reproduction ratios of 1:1 or greater (e.g., 2:1, 3:1, etc.). Rudolf Kingslake gives a broader definition of a macro lens as one "which is well corrected for use over a wide range of object distances."^[9]: 320 Using this latter definition, many photographic lenses designed and sold with "macro" focusing ranges feature a maximum reproduction ratio between 1:2 and 1:1. In general, this significantly larger than non-macro lenses, as those often are designed with a maximum reproduction ratio of approximately 1:10 for practical and optical considerations.^{[10][11][12][13]} ,

Since the size of the image on the negative or image sensor rarely is the subject of discussion except in technical photography and film-based processes, the final image (e.g., as printed, displayed in a magazine, or on a web page) is a more relevant measure to determine the ultimate reproduction ratio. In this sense, the definition of the ultimate reproduction ratio compares the size of the displayed image with the actual size of the subject. Because the displayed image (photographic prints and web pages, etc.) are usually larger than the film frame or image sensor, the ultimate reproduction ratio is the product of the optical reproduction ratio (determined by the lens) and the magnification from the sensor to the display. This facilitates displaying the subject at greater than life-size,^[10] and so the final displayed image more commonly lends a photograph macro (i.e., >1:1) status. For example, when producing a 6×4 in (150×100 mm) print using an image captured on a 35 format (36×24 mm) film or sensor, the printing process results in a 4:1 magnification in going from the sensor to the print, and a life-size result is possible with a lens having only a 1:4 reproduction ratio.^[14][15]

Reproduction ratios much greater than 10:1 are considered to be photomicrography,^[b] often achieved with optical microscopes.^[5]: 5

History

The term photo-macrograph was proposed in 1899 by W. H. Walmsley for close-up images with less than 10 diameters magnification, to distinguish from true photo-micrographs.^[16]

Development of the photo-micrograph led to the evolution of macro photography.^[17]

One of the earliest pioneers of macro photography was Percy Smith, born in 1880. He was a British nature documentary filmmaker, and was known for his close-up photographs.^[18]

Equipment and techniques

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

Lenses with a "macro" focusing feature are specifically designed for close-up work, with a long barrel for close focusing and optimized for high reproduction ratios, are one of the most common tools for macro photography. Most modern macro lenses can focus continuously to infinity as well and can provide excellent optical quality for normal photography. True macro lenses, such as the Canon MP-E 65mm f/2.8 1-5x Macro, Laowa 25mm f/2.8 2.5-5X Ultra Macro (a relatively shorter focal length) or Minolta AF 3x-1x 1.7-2.8 Macro, can achieve higher magnification than life size, enabling photography of the structure of small insect eyes, snowflakes, and other minuscule objects. Others, such as the Infinity Photo-Optical's TS-160 can achieve magnifications from 0-18x on sensor, focusing from infinity down to 18 mm from the object.

Macro lenses of different focal lengths find different uses:

• Continuously-variable focal length – suitable for virtually all macro subjects
• 45–65 mm – product photography, small objects that can be approached closely without causing undesirable influence, and scenes requiring natural background perspective
• 90–105 mm – insects, flowers, and small objects from a comfortable distance
• 150–200 mm – insects and other small animals where additional working distance is required

Barrel extension

Optical scheme of macro photography using extension tube

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.

Bellows fitted between an SLR and reversed lens

Extending the distance between the lens and the film or sensor, by inserting either extension tubes or a continuously adjustable bellows, is another equipment option for macro photography. The further the lens is from the film or sensor, the closer the focusing distance, the greater the magnification, and the darker the image given the same aperture. Tubes of various lengths can be stacked, decreasing lens-to-subject distance and increasing magnification. Bellows or tubes shorten the available maximum focus distance and make it impossible to focus to infinity.

Auxiliary lenses

Typical close-up auxiliary lens

Optical scheme of close-up macro photography with an auxiliary lens

Placing an auxiliary close-up lens (or close-up "filter") in front of the camera's lens is another option. Inexpensive screw-in or slip-on attachments provide close focusing. The possible quality is less than that of a dedicated macro lens or extension tubes, with some two-element versions being very good 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. They are typically designated by their diopter, and can be stacked (with an additional loss of quality) to achieve the desired magnification.

Selective focus

Photographers may employ view camera movements and the Scheimpflug principle to place an object close to the lens in focus, while maintaining selective background focus. This technique requires the use of a view camera or perspective control lens with the ability to tilt the lens with respect to the film or sensor plane. Lenses such as the Nikon PC-E and Canon TS-E series, the Hartblei Super-Rotator, the Schneider Super Angulon, several Lensbaby models, the Zoerk Multi Focus System, and various tilt-shift adapters for medium format, allow the use of tilt in cameras with fixed lens mounts. Traditional view cameras permit such adjustment as part of their design.

Reversed and stacked lenses

Reversed-lens macro photography optical scheme

Optical scheme of macro photography using reversed lens and telephoto lens

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

Ordinary lenses can be used for macro photography by using a "reversing ring". This ring attaches to the filter thread on the front of a lens and makes it possible to attach the lens in reverse. Excellent quality results up to 4x life-size magnification are possible. For cameras with all-electronic communications between the lens and the camera body specialty reversing rings are available which preserve these communications. When used with extension tubes or bellows, a highly versatile, true macro (greater than life size) system can be assembled. Since non-macro lenses are optimized for small reproduction ratios, reversing the lens allows it to be used for reciprocally high ratios.

Macro photography may also be accomplished by mounting a lens in reverse, in front of a normally mounted lens of greater focal length, using a macro coupler which screws into the front filter threads of both lenses. This method allows most cameras to maintain the full function of electronic and mechanical communication with the normally mounted lens, for features such as open-aperture metering. The 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 reproduction ratio is 16:1). The use of automatic focus is not advisable if the first lens is not of the internal-focusing type, as the extra weight of the reverse-mounted lens could damage the autofocus mechanism. Working distance is significantly less than the first lens.

Compact cameras and smartphones

Increasingly, macro photography is performed with compact digital cameras and small-sensor bridge cameras, combined with a high powered zoom lens and (optionally) a close-up diopter lens added to the front of the camera lens. The deep depth of field of these cameras is an advantage for macro work.^[19][20] Contemporary small-sensor digital cameras are equipped with high pixel density sensors and possess good resolving power due to advances in sensor technology, which enable them to capture very high levels of detail, rivaling the macro capabilities of a DSLR with a "true" macro lens, albeit often at the cost of greater image noise. Although the lenses fitted many small-sensor cameras have a lower reproduction ratio than a true macro lens (1:1), smaller sensors do not require the same optical reproduction ratio to produce identical framing and equivalent magnification, making macro photography more widely accessible at a lower cost.^[12][21][19]

In the digital age, a photograph is more practically defined as macro when an object measuring 24 mm or less either matches the frame's height or is larger.^[22]

The iPhone 13 Pro series introduced macro photography in the iPhone camera, as well as Samsung Galaxy S21 Ultra, which is also introduced a macro photography in the smartphone camera.

Microscope attachments

Macro photography can also be carried out by attaching a camera to one optical path of a binocular microscope (stereo microscope), making use of the optics of that instrument as the imaging lens for the system. Between approximately 1976 and 1993, the manufacturers Wild Heerbrugg (Switzerland) and subsequently, Leica Microsystems offered a dedicated microscopy system for macro photography, the macroscope line, with improved optical performance for photography at the expense of the stereo imaging facility of the stereo microscope; this system came with a range of dedicated stands, objective and supplementary lenses, and illumination systems.^[23] Following its discontinuation in 1993, Leica continues to offer similar products under the names Z6 APO and Z16 APO.^[24]

• Macro photograph examples
• 
  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
• 
  Headshot of a dragonfly taken with a 100 mm macro lens coupled with a 50 mm lens in reverse at the end
• 
  Ant
• 
  A fern sorus using 4:3 aspect ratio

35 mm equivalent magnification

35 mm equivalent magnification or reproduction ratio is a measure that indicates the apparent magnification achieved with a sensor format smaller than the 35mm film frame size of 24×36 mm (0.94×1.42 in).^[25][26] The term is useful because many photographers are familiar with the 35 mm film format.^{[22][27][28][29][30][31]}

Because an image captured by smaller sensor needs additional magnification to achieve the same display size, an equivalent reproduction ratio can be achieved on a smaller sensor using a lens with a smaller reproduction ratio. Consider a situation where the photographer captures an object measuring 18×12mm at life size (reproduction ratio of 1:1) with a 35mm or "full-frame" camera, resulting in a recorded image with subject measuring 18×12mm (1:1), which occupies 1⁄4 of the frame area (36×24mm).^[32] An equivalent photograph using a 4⁄3" sensor also would record the object into an area occupying 1⁄4 of the frame, assuming the picture will be displayed at the same size. Since the frame size of the smaller sensor is approximately 18×13.5mm, the object would be captured at 9×6mm, which means the required reproduction ratio with the smaller sensor is 1:2, not 1:1.

For example, the 12 megapixel Micro Four Thirds Panasonic Lumix DMC-GH1 camera with a 2× crop sensor only requires a 1:2 reproduction ratio to take a picture with the same subject size, resolution, and apparent magnification as a 12 megapixel "full-frame" Nikon D700 camera, when the images are viewed on screen or printed at the same size. Thus a Four Thirds system macro lens like the Laowa 50mm f/2.8 2X Ultra Macro Lens with a maximum image magnification of 2.0×^[33] is rated as having a "4.0× 35 mm equivalent magnification".^[34]

To calculate 35 mm equivalent reproduction ratio, simply multiply the actual maximum magnification of the lens by the 35 mm conversion factor, or "crop factor" of the camera. If the actual magnification and/or crop factor are unknown (such as is the case with many compact or point-and-shoot digital cameras), simply take a photograph of a mm ruler placed vertically in the frame focused at the maximum magnification distance of the lens and measure the height of the frame. Since the object height of a 1.0x magnified 35 mm film image is 24 mm, calculate 35 mm equivalent reproduction ratio and true reproduction ratio by using the following:^[35]

(35 mm equivalent reproduction ratio) = 24 / (measured height in mm)

(True reproduction ratio) = (35 mm equivalent reproduction ratio) / Crop factor.

Since digital compact camera sensor sizes come in a wide diversity of sizes and camera manufacturers rarely publish the macro reproduction ratios for these cameras, a good rule of thumb is that whenever a 24 mm vertical object just fits, or is too tall to fit in the camera viewfinder, you are taking a macro photograph.^[22]

• Examples of equivalent reproduction ratios
• 
  L: taken with a Micro Four Thirds (2× crop) sensor camera and a 50 mm macro lens at 1:2 magnification; R: taken with a full-frame (35 mm) sensor digital SLR camera and a 100 mm macro lens at 1:1 magnification.
• 
  Top: taken with a full-frame (35 mm) sensor digital SLR camera and a 100 mm macro lens at 1:1 magnification; Bottom: taken with a Micro Four Thirds (2× crop) sensor camera and a 50 mm macro lens at 1:2 magnification.

Technical considerations

Depth of field

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

Limited depth of field is an important consideration in macro photography. Depth of field is extremely small when focusing on close objects. A small aperture (high f-number) is often required to produce acceptable sharpness across a three-dimensional subject. This requires either a slow shutter speed, brilliant lighting, or a high ISO. Auxiliary lighting (such as from a flash unit), preferably a ring flash is often used (see Lighting section).

Like conventional lenses, macro lenses need light, and ideally would provide similar f/# to conventional lenses to provide similar exposure times. Macro lenses also have similar focal lengths, so the entrance pupil diameter is comparable to that of conventional lenses (e.g., a 100 mm f/2.8 lens has a 100 mm/2.8 = 35.7 mm entrance-pupil diameter). Because they focus at close subjects, the cone of light from a subject point to the entrance pupil is relatively obtuse (a relatively high subject numerical aperture, to use a microscopy term), making the depth of field extraordinarily small. This makes it essential to focus critically on the most important part of the subject, as elements that are even a millimetre 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, for example when photographing skin cells. Alternatively, more shots of the same subject can be made with slightly different focusing lengths and joined afterwards with specialized focus stacking software which picks out the sharpest parts of every image, artificially increasing the perceived depth of field of the resulting image. For analog film cameras light scanning photomicrography (LSP) has been used to overcome depth of field limitations. This technique uses a thin slit of light to illuminate an object as it is moved perpendicular through the plane of light to form the image. If the slit of light is narrower than the DOF the entire object will be recorded on film in focus.^[36][37]

Lighting

The Medical-Nikkor line of lenses have an integrated ringlight to provide even close-up illumination

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 difficult 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 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.

Ring flashes, with flash tubes arranged in a circle around the front of the lens, can be helpful in lighting at close distances.^[38] Ring lights have emerged, using white LEDs to provide a continuous light source for macro photography, however they are not as bright as a ring flash and the white balance is very cool.^[39]

Good results can also be obtained by using a flash diffuser. 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 reflections and providing more even lighting.

Exposure adjustment

Effective aperture for typical magnifications

RR	m	Effective f/	Open by n stops
1:10	1⁄10	×(1.1)	0.25
1:8	1⁄8	×(1.13)	0.25
1:5	1⁄5	×(1.2)	0.5
1:4	1⁄4	×(1.25)	0.75
1:3	1⁄3	×(1.33)	0.75
1:2	1⁄2	×(1.5)	1.25
1:1.5	2⁄3	×(1.67)	1.5
1:1	1⁄1	×(2)	2
2:1	2	×(3)	3.25
4:1	4	×(5)	4.75
5:1	5	×(6)	5.25

When the close-focus ability of the lens is achieved through mechanical extension alone, the exposure must be adjusted to compensate at close distances. If m is the magnification of the subject, where m is the reciprocal of the reproduction ratio, the effective f-stop is determined by the formula:^[7]: 99

${\displaystyle f_{eff}=f\cdot (1+m)}$

For example, if the metered exposure calls for a shutter speed of 1⁄8 s and an aperture of f/2.8, when the lens has been extended to achieve a reproduction ratio of 1:3, the aperture should be set to f/2.1, resulting in an effective aperture of f/2.8. This is equivalent to opening the proper aperture setting of f/2.8 by 0.75 stops.

Recent macro lens designs have taken inspiration from zoom lenses, and the focal length can change in conjunction with lens extension as the lens is focused closer,^[40] which complicates the exposure compensation calculation. Modern cameras which are equipped with through-the-lens light meters and which can detect the lens type will automatically adjust the exposure based on the focusing distance and the amount of light passed to the metering sensor(s).

Chromatic aberration

Many macro lenses are characterised by a high amount of chromatic aberration, especially when using reversed-lens, extension tube or close-up lens. Some macro lenses, called apochromatic lenses, are designed to better control this, such as the Laowa 100mm f/2.8 2x Ultra Macro APO and the Sigma APO MACRO 150mm F2.8.

See also

• Forensic photography – Art of producing an accurate reproduction of a crime scene
• Macroscope (Wild-Leica) – Optical microscope
• Micrograph – Process for producing pictures with a microscope
• Time-lapse photography – Filming at a lower frame rate than the viewing rate
• Underwater photography – Genre of photography

Notes

1. An alternative definition for macrophotography, not discussed in this article, refers to the art of making very large photographs,^[5]: 4 such as those generated by the Polaroid 20×24 camera.
2. Photomicrography should not be confused with microphotography, the art of making very small photographs,^[5]: 4 such as for microforms.^[7]: 45 Unlike most other lens makers, Nikon designates its macro lenses with a "Micro" prefix because of their original use in making microform.