Originally posted by Na Horuk Btw, Pentax makes two lenses that are meant for portraits. The DA* 55mm and the FA 77mm ltd. These are designed for bokeh, skin tones, stuff like that. But they are a little expensive.
If you don't mind going manual, there are many more choices that don't cost too much, but I guess you already have that and now want AF and everything
It's true, these
are the lenses that fit the bill. As others have mentioned, they might not be as far out of your price range as you think. I wouldn't be afraid to get either one used - in fact my FA77 was approx. $550 a few years ago - I made a deal to buy it and an FA43 for $1000 even.
If you really want to stay cheaper, then the M100/2.8, A100/2.8, F/FA135, and some of the old Pentax 85s (which I've never used) would do the job very well. Don't worry about the longer FL - there's no overlap with the lesser performance you'll get with a 70-200 lens. And at those focal lengths f/2.8 gives you excellent subject isolation.
If all else fails you can get the DA70 (but I'd still hold out for the FA77). In any case you're right - the FA50/1.4 (or any of its close relatives) will underperform for the money - at least for your application (which is why I sold all 3 of my Pentax AF 50s).