Having seen a few questions on here relating to macro photography I thought I'd put this together. Hope it helps.
What is macro?
Macro, by definition, is photography at 1x magnification and above. Anything less would be defined as "close-ups" rather than "macro". For the purposes of this short article the term macro will also include close-ups which are not quite 1:1 (or life size).
For someone starting out in macro photography the array of equipment available can be confusing and I will try and address the various options and prices open to photographers.
Close-up diopters
Diopters or close-up lenses are simply magnifying glasses that you can screw onto the front of a lens to increase object size. The Canon 500D is a small double-element lens that threads onto the filter threads on a standard (non-macro) lens. It allows that lens to be focused at a much closer distance - resulting in a higher magnification of the subject. It is intended to be used on lenses with a focal length of 70mm-300mm. When I started shooting macro last year I used the Canon 500D on the front of a standard 70-200mm zoom lens (Nikon also manufacture similar products – the 5T & 6T). Whilst the quality of a diopter is good it will not match a dedicated macro lens but they are excellent if your budget is tight or space and weight is at a premium when travelling.
Here are a couple of examples of images taken using the Canon 500D:
Extension tubes
Extension tubes offer an alternative at a reasonable cost, especially if you buy used or find a good deal on third-party products such as from Kenko.
The basic theory with extension tubes is that for 1:1 magnification, you need the same number of mm of extension as the lens you are using, e.g. a 50mm lens would need 50mm of extension in order to achieve 1:1 magnification. Obviously, the longer the lens you use the greater the extension you would need and going past a certain number results in an unwieldy amalgam of lens plus extension tubes. Unfortunately, it isn't as simple as just using a 24mm wide-angle lens with a 24mm extension tube to achieve 1:1 either, since your working distance will be virtually non-existent.
Dedicated macro lens
Macro lenses come in various sizes, from the ever popular 50mm and up to 200mm. All the major manufacturers produce a range of lenses including Nikon, Canon, Sigma, etc and prices can vary accordingly. I have used the Sigma 180mm macro lens for just over a year and I have been very pleased with it’s performance although it is quite heavy, Sigma also make a 150mm version which seems to get good reviews. A longer lens allows for a greater working distance which can be important with nervous or shy subjects and it reduces the distance the camera requires to focus. When this distance is reduced, the magnification is increased. Imagine yourself looking at an object at a distance with your eyes. Now, move your eyes closer to the object. Does it seem bigger?
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. A longer lens will give you more working distance while maintaining 1:1 true lifesize magnification. See below the approximate working distances for various lenses.
Macro Lens: 50mm 105mm 180mm
Working Distance : 1.6 inches 4.7 inches 9.1 inches
Other Options
There are other methods for macro photography such as bellows and reversing lenses but as this is a Pixalo guide to getting started I will leave these out as I believe they are for the more dedicated photographers (also I don’t know much about them!)
Depth of Field (DOF)
DOF in macro photography is very limited, the increased magnification you get with macro comes at the expense of depth-of-field. Depth-of-field is how much of the picture is in sharp focus. There is an inverse relationship between magnification and DOF, the more magnification you get, the less DOF you get.
Another technical difficulty in shooting macro is getting the focus point at the optimal plane. Focusing at the right point becomes critical because of the very limited DOF, so you need to identify the part of the bug that will yield the most drama, and this can depend on exactly what you’re trying to show. On many bugs the eyes lend a dramatic connection between them and us, so that is what you might want to have the sharpest focus. On the other hand, many bugs’ wings have similar structure to a stained-glass window, and you might want to draw attention to those patterns. Whatever it is that captures your eye should also capture the eye of your audience, and that is what you should focus on.
Lighting
Lighting, as in all photographs, is essential to macro photography. You will need to consider the shape and position of your subject, while selecting the proper light. Here are a couple of examples of using natural light, the first was backlit allowing the detail in the legs to show through:
This image again used natural light and with a smaller depth of field the background is nicely out of focus whilst the detail in the raindrop is captured:
You will need to experiment to see if direct lighting will work best for your shot, or if you would be better served by soft or diffused lighting. The key to success with lighting is experimentation and don’t forget to try and select a proper background.
This final image again uses natural light but with a small depth of field, I have always used a smaller aperture when shooting insects but following some excellent advice I have started experimenting with larger apertures which allows me to do away with the flash.
