Macro photography; Close-up photography; photomacrography; macrography
Macro photography is where the subject of the photograph is usually very small in real life, or is a very small detail of a larger object. The final photo you print is normally larger than life-size.
Macro photographs are normally taken from extreme close-up range. Your image, as projected onto the sensor plane, becomes equal to life size or greater. Best results are achieved in macro photography by using a special photographic lenses called a macro lens.
The image on the sensor
The image is normally captured as one of three basic conditions in Macro photography…
- An image projected onto the sensor is a smaller size than the subject (the subject is in a ratio of, say, 1:0.8 with the image on the sensor).
- The image projected onto the sensor is the same size as the subject (the subject is the ratio 1 to 1 with the image on the sensor).
- An image projected onto the sensor is a larger size than the subject (the subject is the ratio ‘n’ to 1 with the image on the sensor which represents a magnification of ‘n’ times).
Lenses and macro photography
The image that is projected onto the sensor is created by the macro lens. The lens elements together give the lens its ability to size the image on the sensor.
Lenses differ in their ability to project the image at different ratios in macro photography. Some lenses may not give a one to one result, meaning the image projected onto the sensor will be smaller than life-sized. Other lenses may give 1:1 or a significant magnification (say, 4:1 – four times magnification).
However, there are a range of other ways to achieve the same end…
- Close-up lenses (close-up rings)
- Reversed lens mounted on the camera using a “reverse ring mount adapter”
- Extension tubes: Extend the lens’ focal length enabling it to enlarge
- Bellows: Extend the lens’ focal length enabling it to enlarge
Macro photography and the printed or screen image
The result of a macro photograph on screen, or as a print, can me very different to the projected size on the sensor. If the macro image on the sensor plane is life-sized the actual printed photograph may be many times larger. The actual visible size on screen, or print, is determined by a number of things including (but not limited to)…
- The magnification factor of the lens.
- A crop (part of the image), taken from the original file.
- Image rendering during post processing.
- The number and size of the pixels in the screen, or ink jets in the printer.
- Post processing to resize the object in the image (Image scaling ).
- Other factors which change the file (for example the conversion from RAW to *.jpg in camera)
Rendering the image
In macro photography the screen or print rendering is rarely the same size as the image when projected onto the sensor. The image from the file is scaled up in proportion to the media it is shown upon. A full frame sensor measures 36mm by 24mm. When an image from that size of sensor is projected onto a screen or print medium it looks much larger. Take for example, a photographic paper size of ‘S10R’ (10 x 15″ or 254mm x 381mm). The 1:1 Ratio image on the sensor of a bee in close-up looks considerably larger when fitted to paper measuring 254mm x 381mm.
Most photographs work the opposite way. A mountain scene several miles across may be represented on the sensor by an image size of less than 20mm. The image is scaled down. It is seen on the print as very small compared to reality.
A macro lens reverses that reduction factor for you to get a larger result. With a macro lens, an ant becomes the same size or larger on the image sensor. Your final printed photograph will show the ant many times larger. if you take a shot of a bee of one centimetre, it might half fill the sensor. In your final image that might represent an image of the bee at four or five centimetres.
Very large reproduction ratios are normally regarded as photo-microscopy – a discipline more like working with a microscope than a camera. High magnifications may reach, for example: 1000:1; Eg. the image on the sensor = 1000 times larger than the image in front of the camera.
Working in extreme close-up range with your subject can create problem for you in macro photography. The depth of field is very shallow when focusing so close. Typically you may have only a few millimeters in the sharp zone of your image. As a result you may need a small aperture to help maintain the sharpness. So, you might need longer exposures which makes capturing moving objects more difficult. Strong lighting may also be needed for you to get good results with a macro lens.
Lens characteristics in macro photography
Macro lenses may let you magnify objects close up. However, you will find they have other excellent qualities. You can use them as ordinary lenses when focused at normal ranges. For example, many 100mm macro lenses produce high quality portraits.
Macro lenses are often considered to be suited to specific work:
- None macro lens adapted with extension tubes or bellows – suitable for all types of macro photography.
- 35–80 mm – suited to product and still life photography; dead or immobile biological samples.
- 80–110 mm – biological details, insects, plants, and small objects from a comfortable distance.
- 120–200 mm – insects, plants, and small animals (useful because the lens can be further away).
Comments, additions, amendments or ideas on this article?