Hello fellow pentaxians!

Just wondering if anyone has experience in or thoughts about buying older second hand pentax lenses?

I'm looking for a new fast portrait lens (50mm f1.4 to f2.0) and have found a fair few on ebay that look quite good for around $100.00. They are mostly older lenses with manual focus etc and that doesn't bother me at all.

It looks like this is probably the cheapest way for me to get a nice fast lens for minimal cost. I don't really want to go and spend $500 to $1000 for a new lens (as much as I'd love to!). I'd just like to get something that still takes good shots while I am still in my hobby phase. If I was to ever go semi-pro then I would obviously look at upgrading.

So...any thoughts? here are some links to lenses I have been looking at.

http://cgi.ebay.com.au/ws/eBayISAPI....=STRK:MEWAX:IT

http://cgi.ebay.com.au/ws/eBayISAPI....=STRK:MEWAX:IT

http://cgi.ebay.com.au/ws/eBayISAPI....=STRK:MEWAX:IT

http://cgi.ebay.com.au/ws/eBayISAPI....=STRK:MEWAX:IT