What is the purpose of having a shutter speed of 1/1000? Can you tell the diffrence between 1/500 and 1/1000 or even higher? For action, gun fire, explosions I know that a high shutter speed is good to capture it all, but how do you know what speed to have it at? Is there a good rule of thumb?

It all depends on what you want to shoot. Im doing a WW2 film right now and I like the 1/48 for filming talking and when the action gets going switch too 1/250 and shake the camera around- it looks like something from Saving Private Ryan on the D-Day landing.
For the higher shutter speeds you notice it will get darker and darker this is because the lens it opening more during that amount of time and it processes it frame so it is nice and clean with a pure shot. Remeber test with different settings and look at them in post for fun.

The higher you go, the more the light is crushed and the image gets more "crispy" You will also get some vertical smearing (flares that are vertical only) if you have bright lights or reflective objects. The higher you go, the smaller the DOF as well...



ash =o)