Since I've embarked upon a streak of lens reviews that will continue for a bit, it's time I made a few comments about what you should be looking at when evaluating the optical quality of a lens.
Most people tend to look for a lens in terms of its focal range and features first. That's because these things define the "function" of the lens. If you need a wide angle lens for your DX body, you don't shop for 300mm and up lenses ;~). In general, focal range and features tend to be the things that narrow your choices down to a few lenses. Once you're down to a handful of lenses, it's the optical qualities that become the attributes that finalize your choice. And that's what we're looking at in this article: what optical qualities matter most? Continue reading here. Note: article has been updated.