Looking for the Swiss-Army Lens
From time to time, I read an online post from someone who, innocently enough, is looking for a 17-500mm f/2.8 zoom that costs no more than $100 and weighs less than a pound. It's gotta have a built-in fill flash on top of it, and produce perfect exposures automatically including compensating for snow and other non-medium toned subjects. Even better if it has the new "auto-composition" feature.
OK, so I exaggerate just a little. But just a bit.
It would be really nice if one could get a lens that covered a wide range and didn't come with its own share of compromises, but such things just don't exist. With computer controlled CAD/CAM techniques, lens design is getting better of course, but you can still expect better performance from lenses that do not push the current boundaries to the extremes. A while back, this meant sticking with primes instead of buying zooms at all, but this is really no longer a truism. The recent Nikon 17-35mm f/2.8 AF-S as well as other current AF-S Nikkors are more than sharp enough and produce professional results in all respects. But I couldn't say the same thing about the longer range zooms like the 24-120mm f/3.5-5.6 or lenses like some of the third-party 28-300mm or 170-500mm lenses.
The name of the high-quality multi-function knife made in Switzerland by Victorinox has generally entered the language as a term to designate any such device that offers an extreme number of features. Unlike with these marvelous gadgets though, lenses that offer too many features generally either have their share of compromises, or extra costs. If you need light weight, buy light weight; just don't expect it to be the best performer possible. If you're looking for one lens that will cover a wide range, be prepared for it to either be big, heavy and expensive, or less expensive with performance to match. If you you're on a budget, you are likely better off buying used gear than new. This way you can maximize your quality and features while keeping your costs down.
If you're looking for a lens with a built-in espresso maker, you'd better get out your welding torch and make your own. When you get it built, give me a call — I might like one some mornings.