[Sandy Hancock]

FA43 or DA*55, unless you're talking about group portraits, then FA31 or the Sigma.

[thornburg]

I'm going to throw my two cents in here, although I'm mostly repeating things other people said.

For posed portraits, you'll want something which is at least capable of focal lengths 50mm or longer.

Primes are fantastic for posed portraits. If you're budget limited, grab a fast manual focus prime. Use Catch-In-Focus if you're not confident in your ability to manually focus well.

A manual focus 50/1.7 can be had quite cheap, and would do nicely.

If you can spend more, you can go for the AF version of the 50/1.7.

If you can spend more, you could get the Samyang/Rokinon manual focus 85/1.4.

If you can spend more, you can get the DA*55/1.4 or one of the Limiteds.


However, if you want to be able to take "portrait" type shots of people who aren't posing for you (e.g. at a party, event, etc), then I would strongly recommend you go for a fast zoom instead.

Unfortunately, the minimum price for a decent fast zoom is about $250 used. They cover a range from there up above $1000.

Consider these:

Tamron 28-75/2.8
Tamron 28-105/2.8
Tamron 17-50/2.8
Tarmon 70-200/2.8

Sigma 17-50/2.8
Sigma 24-70/2.8
Sigma 70-200/2.8

Pentax DA* 16-50/2.8
Pentax DA* 50-135/2.8

[Kozlok]

For wider shots indoors, I love my Sigma 30/1.4. If I have more room, I use a manual focus 50 (most often a Takumar or Helios). For a small sum of money, you can have both. If you still have cash (and room) to spare, the Tamron 70-200/2.8 is a real treasure. My favorite portraits always seem to come from the Tamron.

[yorik]

FA43 or DA*55, unless you're talking about group portraits, then FA31 or the Sigma.

For tight head-shots (inside) the FA 77 is excellent (as is the DA 70, by all accounts). For that matter, depending on how little you are happy to include (i.e., if you like the occasional extreme close-up), a 135 can work quite well too.