Revisiting the EF 100-300mm f/5.6 L: Although I rarely use super-telephoto zooms in my work, once in a while I have an assignment where I need one. I was disappointed with the optical performance of the 75-300 IS and sold it a few years ago, but the classic 100-300 f/5.6 L was available at a very reasonable price at a used camera store in Japan, so I recently bought it. The following is my review of this excellent little lens that was first introduced in 1987.
First released in 1987, the EF 100-300 f/5.6 L was reputed to have the excellent optics of its older FD predecessor. My tests show this reputation to be deserved. With expensive synthetic fluorite and ultra-low dispersion (UD) elements, the EF 100-300 f/5.6 L has excellent sharpness, resolution, and color rendition with almost no chromatic aberration that I can see. Taken with the Canon 10D, the photographs of the blimp below (full size and then cropped) show the excellent resolution of the lens. I'm frankly astounded. You can make out details in the blimp's landing gear -- at an equivalent print size of over 13"x19".
The only negatives to the 100-300L are the "user handling" and relative darkness of the aperture. The zoom is an old-fashioned push-pull zoom. This means if you hold the camera so the lens points down, it will zoom out. It is also hard to make precise zoom adjustments. This is why most modern pro zooms are now twist-to-zoom. The autofocusing motor is the old-fashioned arc-motor drive rather than the contemporary USM ultrasonic-motor. This means the AF is a bit lethargic and there is no Full Time Manual focusing (FTM). The AF/M switch has three positions: regular AF (Macro-Infitinity); Limited AF (2m-infinity) which speeds up distance focusing; and Manual.
The small maximum aperture of f/5.6 isn't great. But it means that this lens is very compact compared to its f/4 or f/2.8 L lens equivalents. With ISO-sensitivity changeable on the fly with Canon EOS digital SLRs and very usable ISO 800/1600 speeds, the small max aperture is less of a liability than it used to be.
Canon also released non-L versions of the 100-300 f/5.6 in standard (EF 100-300mm f/5.6 ) and USM versions (EF 100-300 f/5.6 USM). These are not the same lens. The optical designs are different and do not contain the fluorite elements or ultra-low dispersion glass of the EF 100-300mm f/5.6 L lens. Be sure that you get the L version if you want the maximum optical performance. You can recognize the L version by the red ring around the front of the lens.
Although the 100-300mm range is very useful in the field, Canon never replaced the discontinued 100-300mm L lens with an equivalent L zoom. You can get the more limited 70-200 f/2.8 or f/4 L zooms or the behemoth 100-400 f/4.5-5.6 L zoom, but they never gave us another compact 100-300 L-quality zoom lens. This makes this lens a keeper, in my opinion.
See my website for other reviews of Canon EF lenses. If you know of another pocketable high-quality super-zoom or have other thoughts, please post your comments below.