I would say definitely K-50 from your explanations.
I tried similarly priced Canikons in a shop and the grip is just too small (I'm also a teen...)
Pentax grips feels so much better in hands.
I have no problem using old K-Mount lenses and M42 lenses (M42 with $5 adapter from ebay)
Originally posted by narual I know plenty of very tech savvy people (I'm a software developer), and very few of them would translate their interest in gadgets to an interest in a dslr.
I'm very tech savvy (Web dev, programming, robotics, building computers, etc.) and I've really translated that interest into DSLRs.