Old glass
This is an image of some old beautiful glass, a Tamron 135mm f/2.5 with Adaptall-2.
I'm selling it, a Vivitar 100-200 f/4 and a Soligor 70-150mm f/3.5 simply because I never use them. I bought them just for fun back when I had the Pentax K10D before I knew what focal lengths I'd be using. Old glass is often cheap since they don't have all the automatic features new glass does, but can be very nice optically and allow the photographer to focus on the essentials, if you pardon my pun. Sometimes, shooting a modern DSLR in full auto mode is just like shooting a compact with better IQ. Manual lenses force you to stop and think a bit more. Primes force you to move too compose the shot instead of just turning the zoom ring.
For beginners, old glass gives an opportunity for learning, both photography basics and what kind of focal lengths you use the most. Some people are wide shooters, rarely leaving home without something wider than 20mm. Others, like me, prefer the tele lenses unless you need to really take in a small room. Buying a new DA* 60-250 only to realize that you'd rather use a 15mm prime is no fun, but if you can start using cheap old lenses, you can sell them on after your lesson at a minimum loss.
Pentax is great for this -- they have kept the K-bayonet mount since 1975, so there's a lot of older optics available.
