The ISO/ASA rating isn't completely irrelevant here. If it is a bright day then you might need very slow ISO ratings to get the exposure you want and the relatively long shutter speeds.

Even if your camera doesn't go as low down the ISO range as you would like there are ways round it. You can use neutral density filters (which I think are basically sun glasses for your camera) to reduce the amount of light coming into the lens, thus allowing lower shutter speeds.