[Editors Note: This week is Macro week here on DPE with Rob Sheppard. We'll be having a macro tip every day, make to sure to check them all out!]
A lot of people believe the only way to get quality close-up photographs is with a macro lens. There are some advantages of a macro lens which I will cover in a couple of days. The big disadvantages of a macro lens are that it is just one lens and the cost.
A really great and cost-effective way of getting close-up images even down to 1:1 and magnification is to use extension tubes. Extension tubes let you get quality close-up work with nearly any lens you now own. These are simply tubes that fit in between your lens and your camera body. There are no optics within these tubes, just connections between your lens and camera body.
As you move the lens away from your camera body, it can focus closer. In the “old” days of photography (that really weren’t that long ago), before lenses had internal focusing, all lenses focused closer by moving the optical part of the lens farther away from the camera body. Extension tubes simply extend that distance even farther.
Because extension tubes attach to the back of your lens, you can attach them to any lens and make almost any lens act like a macro lens. They work best with moderate focal lengths of 40mm and higher. Wide-angle lenses often do not work well with extension tubes because the tubes cause them to focus so close that they focus inside the lens! Extension tubes work great with zooms and telephotos. They come in different sizes because how much of an effect they have is dependent on their size and the focal length of the lens.
Since extension tubes have no optics, there is no degradation of image quality from the lens. You may find that some lenses give you absolutely spectacular close-up images. You may also find that some lenses don’t look very good when used with extension tubes. This is not the fault of the extension tubes but rather the fact that the lens was never designed to handle close-up subjects. There’s no way to know this unless you try extension tubes with your lens.
You will find that most lenses look pretty decent with extension tubes, especially if you use f-stops that are in the middle range of f-stops on that lens. Images shot wide open can be very striking, but you may lose some sharpness. Images stopped way down, for example, using f/16 or f/22, will often look worse than any other setting. This is because diffraction effects from the small aperture actually increase when you get close and degrade image quality.
Another option for high-quality close-up work is to use an achromatic close-up lens (or filter). These are highly corrected lenses that screw into the front of your lens. Canon makes some popular ones, the 500D and 250D, that can be used on any brand lens with the appropriate filter size or filter ring adapter. Hoya also makes them. I really like these lenses for use with wide-angle focal lengths. They allow you to get in really close with a wide-angle that you would not be able to do in any other way.
These also work really well with zoom lenses, although for any focal length, the ultimate result will depend on the original lens. That is not necessarily based on how much you spent on the lens as it depends more on how that lens deals with the added optics of the achromatic close-up lens.
For a continuing look at digital photography, especially nature photography, check out my blog at www.photodigitary.com. I am also on Twitter @robsheppardfoto.