I've just bough secondhand Oly c-5050. But I've trouble using P-modes if I want to shoot indoor. If I set the flash to auto, the picture I take will be dark. I must set the flash to slow, but this will change shutter speed to slow too. And the shutter speed is the same if I set flash to 'no flash'. Anyone can help me ?? Or I must bring the camera to Olympus service centre??? Because I think my built-in flash is damaged. Thanks.