Pentax Lens Recommendations?

I currently have a Pentax K20 - and the only lens I currently have (2nd hand) is a Tamron 18-200mm. I haven't been all that impressed with it's focus (or often lack of focus). Because it's the only digital I've used, I don't really have much to compare to aside from other photographers works.

I'd like to focus on more close range work - portraits mostly, but also birds and wildlife so I will likely need a variety of lenses including a decent telephoto.

What recommendations do you have to help me get started on the right path? Not looking to make the switch to Canon or Nikon. There must be lenses available for Pentax that will give me the results I'm hoping to achieve!

Let's see. You have different needs - most wildlife will not let you get very close for the "close range work" unless you have a remote system that triggers when its motion sensor is tripped. That said...

The 50-135mm f2.8 is nice and fast. The focus can be a little soft at the extreme end, but not to the point where it bugs me. Con? AF motor is a titch slower than I'd like for action shots, but that might be PEBKAC - I don't do a lot of action photography in general. Paid about $1000 USD, but the price has gone up since.

Sigma 18-55mm f2.8: it's a very nice wide lens - definitely a big step up from the kit lens. Fast, AF is pretty good. I like this for landscapes and some portraits. I don't remember what I paid...around $600 or so? It's my go-to lens when I want to capture that vast, sweeping landscape.

The plastic 50mm f1.4 lens: I really like it. Fast as hell and it's a good, solid portrait lens. $400-ish?

I also have the 43mm f1.9, and I use this when I shoot portraits in small spaces. Definitely a good portrait lens.

The 35mm f2.4 is also recommended, but I've not tried it myself, but it might be a good starter portrait lens - about $200. Don't let the low price deter you; it's due to its plastic body and lack of manual aperture control (you set it via camera dials).

On my wish list is the 300mm f4 ($1400) or new 560mm f5.6 ($7000) AND the new 2x teleconverter ($600-$700) for wildlife photography. I have a crappy 30yo Solignor that works out to be about 460mm on my K5, and I just adore having that big of a zoom. But the IQ is horrible; I'm keeping my eye out for inexpensive alternatives while I save up.

If you'd like thorough, in-depth reviews of these lens or any other pentax lens, hit Pentaxforums.com. Great resource for when you're shopping, and the community is growing.