Will I just got a Pentax K20d which came with a kit lens 15-55mm. That's all I have right now. I decided that I want to get me two more to last me for a little while. So after reading your thread on the Tamron 17-50mm f/2.8 I decided I'll get that one too. That leaves me with one more to get and I thought it should be a prime. A lot of people have told me to get a 50mm others have told me to get an 85 and some even a 100mm. Which one is the best... Which should I get. I do portraits, head shots, and modeling portfolios. I'll do some inside work but I like shooting on location (outside) too. Thanks in advance!