Macro photography is cool, really cool. Any photograph that makes the subject appear larger than life captures our attention. Think: insects that look giant, photography of flowers or leaf petals. Unfortunately, macro photography requires special macro lenses. Macro lenses are designed to have a closer focusing distance than your regular lens. To really zoom in on a subject in macro photography, even with a telephoto range focal length, you’ll want to have the front of the lens as close to the subject as possible to fill the frame as much as possible. On regular lenses, generally the closest focusing distance is a foot or more. Lenses with telephoto focal lengths generally cannot focus closer than a few feet. That just doesn’t cut it. On a macro lens, the closest focusing distance (the distance from the front of the lens to the subject) will be a foot or less. Couple that with a focal length of 100mm and you can make a tiny insect occupy the entire frame.
But lenses are expensive, and Macro lenses are no exception. Before splurging hundreds if not thousands on dollars on a macro lens, only to find you don’t enjoy the set up and prep work to do really good macro photography, there is a less expensive alternative: a macro extension tube. A couple of months ago, I “splurged” for the 10 dollar nameless brand to try my hand at macro photography. For 10 dollars, I can’t say it was a waste.
So what is an extension tube? Macro extension tubes are simply columns of air that attach to your lens to increase the distance between the lens and camera sensor. I’m terrible at physics so I’ll simply say that by doing this, they decrease the minimum focusing distance from the lens to a subject. They also sell for as little as 10 dollars or so. “Brand name” extension tubes can run up to $150 which still pales in comparison to what a macro lens itself costs.
So what’s the trade off? There are a few. The no-name brand tubes are literally just columns of air. They separate the lens from the camera and maintain no electrical communication between the two. This does a few things. First, autofocus is lost. This isn’t a big deal if you’re shooting a flower indoors with your own special lighting setup. If you’re trying to focus on the honey bee that is flying from flower to flower, it can be a challenge. I know, I’ve tried. Second, on lenses with automatic aperture adjustment (which is just about all lenses), the loss of electrical connection causes the lens to shoot wide open. Unless the lens has a manual aperture adjustment (and virtually none do), the lens defaults to it’s widest aperture.
The ability to shoot only at the widest aperture is a big deal and probably limits the usefulness of cheap extension tubes. Remember, depth of field is related to subject distance, aperture and focal length. The closer the subject and larger the focal length, the narrower the depth of field will be. With macro photography, you’re dealing with incredibly close subjects, narrowing your depth of field to a few millimeters. Forced to shoot wide open, at maximum aperture, forces your depth of field even narrower. Ideally you would want apertures towards the f/16 end of the spectrum to give you a few extra millimeters in the depth of field. This razor thin depth of field coupled with manual focus makes for a lot of pictures that are not focused on the desired subject.
With the brand name macro extension tubes, you do at least maintain electrical connection between the camera and lens and therefore preserve both autofocus and your ability to set the aperture. Of course, these tubes are more expensive. All macro extension tubes will limit your far focus in a way that a true macro lens would not. Again, with the physics. Simply put, any extension tube will cause you to lose focus at the far end – you will not be able to focus on subjects more than a few feet away. So, if you’ve snapped on your extension tube, you’re probably not going to be able to do any other type of photography for the day.
Overall, for a few bucks, it is hard to say that cheap macro extension tubes aren’t worth it. I’ve played around with mine, and come out with a few images that I like. All my work with the tubes has been outdoors on moving subjects and I’m sure I’ll have better success with stationary subjects. I haven’t splurged for the brand name tubes because I figure that if I’m that committed to macro photography, I should just get a true macro lens. The Canon EF 100mm f/2.8L IS definitely calls out to me.
Whether you are using a cheap off label extension tube, or a true macro lens, remember that with macro photography you’re dealing with an extremely narrow depth of field and likely a small aperture. Therefore, use a tripod if able, and remember that particularly for indoor stationary subjects, ancillary light will usually be required but a flash will not work because the subject is too close.Tags: Camera Operation, Equipment, Lenses, Photography Tips