Originally posted by miltona580 If something were to hit a metal lens hood, you risk damage to your filter ring at least, and possibly the front element.
On the other hand, if something were to slam directly into the front element, the whole lens would take the brunt of impact. In the worst case scenario, dropping the lens, if it lands on the front element, that's the end of the lens. If there's a hood attached, the filter threads may get wrecked but at least the lens will live. Plastic hoods may be best because they will crack or shatter on impact, thus transmitting none of the blow to the lens or threads.
With the small built-in hood of the FA31, this is a bit different, of course. The *primary* purpose of a lens hood should not be protection but there's no reason not to tout it as a secondary benefit.