I'm looking for a digital camera, at least 4Mp, at least 5X optical zoom preferably with threads for a 2X adaptor and good low light capability. Reasonable price! Problems I've heard of include: CA (purple fringes), poor low light focusing, long shutter delay, poor F stop rating. My research suggests the Sony DSC F717 is the best compromise but what suggestions or comments do actual users have? What other models have you used or had experience with?