I'm going to try to make this macro series the least bit technical as possible so that photographers of all skill levels can understand it. Please feel free to post questions about the articles or any macro topics that you may have along the way so that I can cover them in a future article.
I've been doing macro photography for about ten years now. I had no clue what I was doing when I first started (even though I thought I did). I was working as a biologist in the desert at the time and surrounded my many incredible photo opportunities. I thought that I could just pick up my camera and go take incredible closeups of plants, wildlife, etc., but it didn't take too long before I realized that it didn't work out that way. I did get some good macro photos, but I was incredibly limited by my lens.
It's not uncommon for photographers to gawk at the equipment that others are using. I've come to realize that this happens most often when I'm doing macro photography. For instance, just yesterday while I was shooting some water droplets on a leaf, a man asked what lens I was using. He was using a standard zoom lens that said "macro" on it, but he wasn't totally pleased with the results that he was getting with his lens. A lot of lenses on the market do have this built-in macro capability, but they aren't true macro lenses. If you're using a lens with this built-in macro capability, you will be able to take macro photos, but you will be limited to what you can capture and you won't be able to capture 1:1 life size macro images. Most everyday lenses have a ratio that is not 1:1, so you're capturing the subject at a smaller fraction of its true size.
So what's the difference between a normal everyday lens and a macro lens? A normal lens has glass elements that move back and forth up to a specified focal distance. When you go get closer than that focal distance, everything is going to be out of focus because the lens elements can't adjust beyond that point. In a true macro lens, you still have moving elements, but they have a larger distance inside of the lens barrel than they would in a standard lens and one of these elements is floating so that the optics can be changed to allow sharp images at all focal distances. So no matter how close I am to my subject, I can always capture a sharp image (provided that my eyes are working correctly and my technical settings are correct)!
There are macro lenses of many focal lengths...50mm, 90mm, 100mm, 180mm, etc. and you chose the focal length of the macro lens just the same as you would any other lens. For instance, if you want to get a close photo of a person from a distance, you're not going to use a 50mm lens; you would use a lens that would give you a little bit more reach. So in the macro world, you would use a lens with a longer focal length to capture images of insects or other wildlife that may become easily spooked by your presence. Macro lenses with shorter focal lengths are great for product shots and other inanimate subjects. I use a mid-range macro lens: the Tamron 90mm/f2.8 macro. This is the oldest lens that I have and one of my very first lenses: it's about 10 years old. It's great for all purposes, but I do have difficulty photographing some insects that are easily spooked. I have used a 180mm macro, but it's a lot heavier and almost always requires a tripod. However, I don't need to get as close to my subject to achieve a 1:1 image with this longer lens.
Close-up diopters and extension tubes are also commonly used for macro photography. While I haven't used them for a long time, I will eventually touch on them in a future article.
Thank you to Albert Yee for the photograph of me photographing. I was capturing the Columbine flower above.
Water droplets: Canon 20D with Tamron 90mm Macro; 1/125 sec & f3.5 using natural light
Columbine flower: Canon 20D with Tamron 90mm Macro; 1/160 sec & f4 using natural light