I am on "Auto".
I just changed it to "Shutter Priority", that you can see the config point.
I like taking fotos with my Canon D60... And it is always the same "as faster the shutter speed, as higher must be the ISO (at bad light), as more noice you get on the picture"
With my Canon D60 I need 1/2000 to shut a car with 60km/h sharp (at daylight), so I tryed at Dahua 1/2000 (you have to go to "manual Interval") and that brings a sharp picture, but also noice.
I have a SD card in the camera, but dont use it (I hoped, that all alarm pictures and movies can save on the CD card and parallel on my NAS... but it dont), so I save everything on my NAS.
Than access with my WIN PC and wath the pictures with Irvanview and the movies with the dahua "smart Player" (sadly the play dont save the movie ratio, you have to change it to 16:9).