Kholi- you're using M-mode on the top dial and you can set your f-stop & shutter before pressing record?
You can, but it doesn't do anything. Which is very strange. There's no change in the image as far as light transmission goes. I'm sure I'm just overlooking something, but right now it seems as if you can only adjust ISO and EXPOSURE.
And, if you have a non auto lens then F-stop manually. The problem is that there're no internal NDs, so you're gonna have to use the exposure and just deal with whatever "shutter" this thing has employed.