Understanding Macro Photography
Macrophotography is close-up photography, usually of very small subjects. Classically a macrophotograph is one in which the size of the subject on the negative is greater than life size. However in modern use it refers to a finished photograph of a subject at greater than life size.The ratio of the subject size on the film plane (or image sensor plane) to the actual subject size is known as the reproduction ratio. Likewise, a macro lens is classically one lens capable of reproduction ratios greater than 1:1, although it now refers to any lens with a large reproduction ratio, despite rarely exceeding 1:1.
Outside of technical photography and film-based processes, where the size of the image on the negative or image sensor is the subject of discussion, the finished print or on-screen image more commonly lends a photograph its macro status. For example, when producing a 6×4 inch (15×10 cm) print using 135 format film or sensor, a life-size result is possible with a lens having only a 1:4 reproduction ratio.
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 millimetre closer or farther from the focal plane might be noticeably blurred.
There are a number of different ways you can achieve a good macro or close up image.
Example Macro Lens: Canon MP-E65mm
This is a dedicated 1:1 macro lens that does not require any special attachment to achieve true macro magnification. Some telephoto zooms offer macro functions which may not be a “true” macro ratio.
“Macro” lenses specifically designed for close-up work, with a long barrel for close focusing, are one of the most common tools for macrophotography. (Nikon designates such lenses as “Micro” because of their original use in making microforms, but most lens makers use the term “Macro” or “Makro.”) These lenses are optimized for high reproduction ratios. Most modern macro lenses can focus continuously to infinity as well, using complex focusing mechanisms that alter the optical formula. In most cases these lenses provide excellent optical quality when used for normal photography, although a macro lens may be optimized to provide its best performance at its highest magnification
Macro lenses typically have very short minimum focus distance ratings; minimum focus distance is the “closest” distance you can be to the subject before the lens loses its ability to focus. Short focal length macro lenses have lower minimum focus distance than longer focal length macro lenses. What this means to the macro photographer is “working buy crestor online canada distance”; working distance is the measure of length between the end of your lens and your subject when at a 1:1 magnification ratio. A longer lens will give you more working distance while maintaining 1:1 true lifesize magnification.
Macro Lens: 50mm 105mm 180mm
Working Distance :1.6 inches 4.7 inches 9.1 inches
You can add a teleconverter to increase the working distance of your lens. For example, if you put a 2x TC onto the Sigma 180mm macro lens, you will effectively double the focal length of that lens to 360mm and it will still maintain its true macro 1:1 magnification. But the real benefit of doing this is that it will also double the working distance of that lens to over 18 inches. As an added bonus, you could even gain some extra magnification this way because if you use this combination at the “normal” working distance of 9 inches, you are actually shooting at 2x lifesize
Extension Tubes and Bellows
These are hollow tubes that are placed between a lens and the camera body, and they simply move the lens elements farther away from the film plane, thus increasing magnification. Because there is no glass in the tube (just air), image quality will not be degraded by optics that are of lesser quality than the lens you’re using. Bellows work in the same way.
As a general rule, the magnification you can achieve using extension tubes is relative to the focal length of the lens you use them with, and the “formula” is:
|tube length ÷ focal length = added magnification|
For example, if you use two 25mm extension tubes on a 50mm macro (1:1) lens, then your magnification will be 2:1 (2x lifesize) because your lens was already 1:1 (by virtue of being a true macro lens) and then you added another 50mm (2 x 25mm) of extension tubes which is the same as the focal length of your lens, adding another 1x.
Reversing rings are simply adaptors with the fitting to go on the camera on one side, and a male thread to screw into the filter thread of the lens on the other or a thread on both sides to connect two lenses together (as image above). If you reverse mount the lens directly onto the camera body, the optical centre of the lens is displaced from the film, introducing a short extension. This causes the lens to focus close, and gives a fixed high magnification, and a fixed working distance. The magnification depends on the focal length of the lens, and the displacement from the film.
You have no focus control so you must focus by moving in and out. There are no connections between the camera and the lens, as these are now at the front. You can either use manual exposure, or set the camera to aperture priority auto. Some lenses will only allow you to use a fixed aperture, but you may get some control by moving one of the exposed pins on the lens end. Some fully auto lenses such as EOS do not have aperture rings so you are unable to set the diaphragm manually. These lenses will have to be used at full aperture.
Close Up Lenses
Besides a true macro lens, close-up filters are the easiest to use, but afford the least magnification. They are diopters that screw onto the threads on the front of your lens (macro or non-macro) that magnify what’s in front of them, kind of like reading glasses for your lens. These filters come in a variety of “powers” and are produced by many different manufacturers.
This is suitable for most everyday objects.
If you want to use natural light, replace the lights with a window on one side and a reflector on the other. You can use tissue paper or a diffuser to soften the light more if needed or use a reflector or kitchen foil to add in some harder light.
A light tent gives a very diffused light that softens the light and reduces glare that makes it most useful for photographing shiny objects. You can buy collapsible light tents for around £20 or you can make your own using a cardboard box and some tissue paper.
Most of this information has been compiled from sources on the internet including http://en.wikipedia.org/wiki/Macrophotography
There are many websites offering advice on macro photography, here are just a few of them.
Some technical tips…
… and some inspiration!