Originally posted by Heelers Isn't the Sigma now discontinued? Lens availability would be a major consideration in this choice. I'm currently seriously considering a switch away from Pentax for this very reason.
What lens are you looking for that isn't available?
"Find the lens you love, buy the camera it goes on."
Switching brands because you might have something you want in the future that isn't available in your mount, would probably be a little silly.
On the other hand, if there's a lens you have to have that isn't available in your mount then sell everything and get it.
Camera bodies come and go, but your dream lens can be used pretty much forever, or at least until it's not your dream lens anymore.
I mean you could switch because of a perceived lack of future lens choices, and then Pentax could come out with your dream lens...
But I agree... Sigma dropping Pentax in the 70-200 is distressing. I might never have bought one, but I liked having the choice. I got a Sigma 8-16 before they were discontinued and am a happy camper because of it. If it's Sigma in a Pentax mount, buy it while you can, it may be short lived. (Spoken in reference to the Sigma 18-35 ƒ1.8 zoom. It would seem to be a great lens, but so were the 8-16, and 70-200, get it while you can if you think you might like it.)