In brief: don’t buy a cheap zoom lens.

When you’re learning a craft, the best tool to use is the one that shows you the limits of your ability. It’s the eight-inch chef’s knife, the bolt-action rifle, the fast normal prime lens. It exposes your shortcomings long before any of its own flaws come into play. The perfect tool for a student to use isn’t the one that does anything you want—it’s the one that makes you choose what to want.