The Focal Lengths Of Macro
Q) I want a macro lens, but I don’t know which to choose. I see that there are three sizes available from Canon: 50mm, 100mm and 180mm. Which is best?
A) Both Canon and Nikon, as well as a few other camera and lens manufacturers, give us a selection of macro lenses. They usually come in three distinct focal-length ranges. The shorter focal length, which ranges from 50mm to 65mm, is designed for close-up work, where it’s not critical to have a lot of working room between the subject and the lens, and where a fair amount of magnification is needed. The main disadvantage to this group is the lack of working distance, and at higher magnifications, it may be difficult to get flash into the subject.
The second group ranges from 90mm to 105mm, and is considered to be the most versatile overall. It’s compact in size, allows considerable working room and offers good magnification when extension tubes are added. If you could choose only one macro lens, this would be the one.
The third group, actually macro-telephoto lenses, usually ranges from 180mm to 200mm. The two advantages offered by these lenses are the extensive working distance (four times that of a 50mm macro) and, because of their telephoto nature, they tend to throw backgrounds nicely out of focus when used with a large aperture.
A fourth macro lens is the Canon 65mm (Canon MP-E 65mm). This lens offers magnifications of 1x to 5x with a full-frame camera. If you’re looking for high magnification, this lens has no equal.
I used a Canon 180mm macro to photograph these spring flower buds in Colorado. The longer focal length of the 180mm lens kept the background out of focus while I rendered the buds sharp using five exposures and Helicon Focus software. The exposure for each capture was 1/20 seconds at ƒ/11 using a Canon EOS 5D D-SLR.