Casio EX-F1: changing shutter/aperture
 

It would seem that changing the Aperture or Shutter speed applies ONLY to HS-movies. STD and HD are totally unaffected!

So changing the Shutter speed applies ONLY to HS-movies. But because HS300 normally uses 300 frames per second, only shutter speeds higher than 1/300 are applied. So you can use for example the shutter speed of 1/4000 and it works, but if you use something like 1/60, well, of course it won't work. :)

It seems strange that changes to Aperture and Shutter speed work only in HS-movies but not in STD-movies or HD-movies.