In addition to the aforementioned L series lenses most other Canon EF lenses fall into a number of broad categories. Note, however, that these are not official Canon-named categories. As far as Canon is concerned, EF lenses come in two categories - L and all the rest. Nonetheless these informal categories are useful to keep in mind when lens shopping.

Category 1 - consumer lenses.

At the bottom of the consumer line are the cheapies - ultra-low cost, low-quality, slow lenses with plastic mounts and no distance scales. Most of the kit lenses - 28-80 and 28-90 lenses with typical aperture ranges of 4.0 to 5.6 - fit into this category. These lenses are built to be sold as inexpensively as possible and don’t have very good optical quality. The only exception to this basic rule is the 50mm 1.8 II - plastic lens mount - which has excellent optical quality despite its cheap build quality, because it isn’t a zoom lens like all the others. The cheapies are easily recognizable by their all-plastic construction and straight, parallel-sided lens barrels. Most of the late-model cheapies are identified by the silver (chrome) ring around the end.

Am I being a huge snob by calling them “cheapies”? Maybe, but the point is that Canon optimize these lenses for cheapness. They want products to sell in massive numbers in shopping mall/high street camera shops and department stores. This market does not, it seems, place a great deal of value on image quality - cheap prices for impulse buys are everything. That’s great for Canon’s balance sheet, but frankly, if I’m going to be dealing with the hassle of carrying around an SLR camera I want at least half-decent optical quality for the attached lens. Otherwise I think it’s a lot easier just to carry around a cheap lightweight point and shoot camera.

Category 2 - midrange zooms.

In the midrange are better lenses with improved optics, sturdier build quality, metal mounts and distance scales. These often have ring USM motors. The 24-85 3.5-4.5 USM, 28-105 3.5-4.5 USM and 100-300 4.5-5.6 USM are typical examples. They’re decent consumer lenses but don’t have the optical clarity of the pro lenses, especially when shooting wide open. However, they generally cost a fraction of the price of the top of the line stuff. These lenses are generally fairly elegantly designed, with slightly rounded and tapered lens barrels, and usually have easy to grip ribbed rubber zoom rings rather than bare plastic.

There are also older low-end zooms with decent optical quality, such as the 28-70 3.5-4.5 II, which don’t use modern USM drives but which nonetheless offer good value for money on the used market.

Category 3 - inexpensive primes.

Canon also sell and have sold a number of prime (ie: non zoom) lenses with acceptable optics and average build quality (usually with noisy motor drives, metal mounts and distance scales), such as the 28mm 2.8 and 50mm 1.8 (metal lens mount). Despite their low cost and pretty unremarkable construction they can provide quite good photographic results.

All lenses in this category are mostly normal or near normal lenses - no super wide angles and no long telephotos. The designs generally date back to the early days of the EOS lineup, so they tend to look a bit old-fashioned, style-wise. Canon just haven’t seen the need to update any of them.

Category 4 - good primes.

This is a group of prime lenses which offer excellent optics and decent build quality, but which don’t really need and thus don’t use ultra low-dispersion glass or calcium fluorite crystals or other hallmarks of L-class lenses. Remarkably good lenses like the 85mm 1.8 and the 100mm 2.8 macro fit into this category. Most have ring ultrasonic motors. They generally resemble the category 2 lenses - slightly rounded and tapered lens barrels. Optically they are professional lenses in all but the name, though they’re usually not quite as heavy-duty as the fancier L lenses.

Category 5 - specialized lenses.

Canon also make a handful of expensive specialized lenses for unusual applications which I’ll just lump into this category for lack of anywhere else to put them. These include their tilt-shift TS-E lenses, the MP-E 65mm super-macro lens and the DO (diffractive optics) lenses.