'I have used Sigma cameras with the Foveon sensor for sometime now. The results have always been very impressive. The DP2 Quattro has moved the concept on in terms of image size, better high ISO quality and camera processing speed, though Sigma Photo Pro still leaves a lot to be desired. However, I and I'm sure many other Sigma users are frustrated by certain things. Firstly the fact that there is only a fixed focal length lens. And secondly that there is no built-in EVF.'