I have seen creative examples of cars at night taken with a slow shutter speed. And I tried to replicate this during the day. I have tried everything I can: Smallest aperture ever, lowest ISO and exposure to -5. The shutter is set for 30 seconds. What I ended up with is a white picture. Plain white. If only there was 0.005 ISO, but that isn't an option. The lowest can only go up to 100. To make it a perfectly normal picture, I could turn the shutter down, but that defeats the purpose. I need a picture of cars blurred. 30 seconds is a must, any lower and the effect will not be seen. Did you ever try this? I didn't know it would be this hard.