Anyone has any experience with Pentax ist DL camera? I previously used Canon 300D, Nikon D70s and Pentax ist, I found that focus on Pentax ist is Very slow. I dont have any camera at this moment, but I do have a sigma lens that will fit Pentax mount. So, I am again considering Pentax ist DL. My major concern is the focus function, is there any improvement on DL ??? Any opinion? Thanks in advance.