Comments about Sigma Sigma 30mm f/1.4 EX DC HSM AutoFocus Standard Lens for Pentax AF Digial SLR Cameras:

One of the reasons I bought a Pentax DSLR is so I could shoot fast primes that would be image stabilized. So essentially, I bought into the Pentax brand so I could use lenses like this. And the lens has not disappointed. It was my first lens besides the kit lens. And what an upgrade it was. It's great at a party because you can take indoor photos without using flash, allowing you to take more candid photos. And the wide aperture makes for great out of focus backgrounds for portraits.

Pros:
Center is sharp even wide open at f/1.4
Very fast lens, excellent for natural light photos
Fantastic for portraits

Cons:
slight barrel distortion
somewhat heavy
corner sharpness is not great, even stopped down.

I realize this lens costs about as much as my K-2000 camera body, but it really transforms what the camera can do.