I'm an amateur with a Canon EOS 400D/Rebel xti.
I know that any given shot requires it's own recipe for shutter speed, ISO and aperture, and I'm aware of the triad of those three.
I typically shoot in aperture priority mode, but sometimes I want to deliberately get a certain amount of movement in a shot, so go for shutter priority mode.
What is a good starting-point shutter speed when I want to capture the following:
Motion - For example, when taking a picture of a moving car, wanting to get the wheels looking like they're spinning, and the background motion-blurred, but with a good chance of keeping the car itself sharp.
"Slow-synchro" flash - For example at an indoor dinner or (darker still) disco, where you want the subject to be illuminated by the flash and quite sharp, but where the shutter is still open long enough to capture the background lighting.
Thanks in advance.