There is a shutter speed switch on the side of the camera. When I turn it on I can get a shutter speed that I have preselected in the camera menu, i.e., 1/40, 1/50, 1/60, 1/100 all the way to 1/2000. My question is this... what is the shutter speed when the switch is in the off position? Is it 1/30? I am asking this because when the switch is turned on the image gets darker. Set at 1/40 it looks like the image gets darker by a stop. The camera is set at HQ 1920/29.97P.
Yes, shutter off at 29.9 is 1/30th of a second. This will create slightly blurred frames and not what you want. Nominal shutter speed at 29.9p is shutter on at 180 degrees or 1/60th of a second. This mimics the motion of a film camera at 30fps.
Same for 24p, shutter should be on at 180 degrees making 1/48th
At 59i however you're already at 1/60th with shutter off, so leave it off unless you're looking for a "skinny shutter" effect.
Another warning is to check shutter speed when you change framerates, that's when you'll be making a mistake that could haunt you.