1. In low-light and under artificial light conditions, the camera may automatically raise the sensitivity, resulting in noise, loss of detail and autofocus errors. Set the ISO sensitivity to a lower setting, try to improve the scene's lighting, or use the flash.
2. Alternatively, check the camera settings. You might be able to improve your ISO settings, or the camera may have selected a less ideal ISO sensitivity, white balance, exposure compensation/exposure metering or image profile.
3. Confirm the issue by using the camera in fully automatic mode (Green Camera icon or AUTO mode) or try to reset the camera to the factory settings (initialization). Consult your product manual if you're unsure about the reset procedure.