I'll start with clarifying a little terminology. While no precise definition exists for macro and close-up photography, macro is usually understood to be a photograph where the image projection on the film/sensor is at least as large as the actual subject (a 1:1 magnification). Close-up photos have smaller image sizes but are still subjectively close.
|Mushrooms in Shenandoah National Park; taken with |
Canon 100mm macro lens
|Fungus; taken with Olympus Stylus 600|
|Moon Flower; taken with Canon 15-85mm lens with |
12mm extension tube
|Close-up of Palamedes Swallowtail; taken with Canon 400 mm lens|
and 20mm extension tube.
|Carolina Chickadee; taken with Canon 400 mm lens|
and 12 mm extension tube from window.
And finally, extension tubes are an inexpensive way to get into true macro photography. I bought a set of Kenko tubes that come in three sizes (plus they can be stacked) for a little over $100. And don't worry about getting name brand tubes. As was pointed out in one review I read, "the cheaper ones have the same 'low dispersion' air as the manufacturer's." Just make sure there are not a lot of complaints about the autofocus not working. If the electronics are not well designed, autofocus might not work. But otherwise, there really is no reason to pay for the name brand extension tubes.