Okay, so my friend brought his newly bought toy (GH2), and i've finally got a use for all those Nikon lenses i've purchased throughout the years..
The adapter is a Novoflex.

My question is about exposure.

I don't understand, but when the lens aperture is closed to F22., the aperture ring on the Novoflex fully opens, and closes, therefore giving me full range of exposure on the LCD screen.

However, when the lens aperture is set to 1.4 (fully opened), the Novoflex ring doesn't affect the exposure.

This seems counter intuitive. Am i missing something?
Thanks.

I have a Fotodiox adapter that probably operates similar to the adapter you were using. If I set my manual Nikon lens at f1.8 the adapter can't control the aperture. If I set it at f22, the adapter can the adjust the aperture through the entire range. On the lens, setting for each stop below f22, causes the adapter to not be able to get to one stop at the largest aperture.