Implementing a large sensor presented all sorts of problems: the cost of the sensor, the difficulty of designing the lens, the high processing capacity required for the image-processing engine, enlarging the circuit board, increasing the memory capacity, and so on. Until these problems could be overcome, it was generally accepted that DSLRs used large sensors, and compacts used small ones. Eventually, these problems were effectively solved, allowing sensors to be made smaller. However, this involved a trade-off: reduced image quality.
From then on, amateur photographers dreamed of a compact digital camera with an SLR-sized image sensor. A camera small and light enough to carry around everywhere, yet offering the technology for serious photography. Those dreams have come true with Sigma’s DP series.