No existe exposición manual en video en esa cámara, es el motivo por el que voy a migrar a una GH... por eso te engaña, el modo manual es solo para foto, en video lo único que puedes ajustar manualmente es el foco... lastima , porque hackeada los videos se ven tremendos.
Aqui viene mas detallado el tema del control de video:
http://www.personal-view.com/talks/discussion/2713/gf3-stable-settings-topic"M" is for manual control of still photos only. Once you start recording video, the camera reverts to picking aperture, shutter speed, and ISO by itself. If you've got legacy lenses, you can regain control of the aperture (as it is set manually), and the "Flicker Reduction" function can let you lock the shutter speed to 50, 60, 100, or 120, but as of yet there's no way to stop the camera from adjusting ISO automatically. VK has mentioned before that he is working on manual controls for GF2 and GF3, but I've seen no promised implementation date.