I did notice today that my GH2 has a similar issue, using two polarizer as "nd fader" with extreme long exposure but have not seen it in video mode so far and also not when taking pictures with regular shutter speeds. I did use two polarizer and for fun I did try to make a photo with extreme long exposure 40-60 sec blocking max the incomming light with the filters - actually i got a blueish color cast with max settings. I got similar pictures like the ones shown above. First I thought thats maybe due to the double polarizer and extreme light blocking, but hell the images from zeedmanz look very similar, right side has a correct exposed stripe and left side it is outwashed...you have this in video mode ? What shutter speed did you use ?
its your nikon adapter ..not the gh2, it took me over 4 months with my gh1 to finally point out the issue ..first i thought it was the sensor,than the lens,never did it occur to me that it could be the adapter...try this, do the same shot, but this time cover your hand around where the are of the adapter and lens meet and i bet you it will be gone ..its not a tight fit adapter.and letting light in , only my nikon adapter did that ..hope it does work ..
Excellent and thx so much for the hint, this could be the reason. Iam using a Nikon 4/3 adapter with aperture ring and will try it without the adapter. Just wonder that I have never seen any issues so far with "normal" shutter speeds also not when filming in the night, but I have to say that I have never done long time exposure with the Nikon adapter on the GH2 before. Which Nikon adapter are you using now ?
This could be a lot of things. But my first thought was veiling glare cause by a bad lens to camera connection. If your adapter cost less than $200, there's a better than decent chance you could experience this (and other abnormalities) at some point, depending on your shooting conditions. This only get's worse, not better with time and use.
I used .01" thick PTFE(teflon) film with one side adhesive to shim my adapters. It lessens the wear on the mounts and has enough elasticity and slickness to make things tight without binding.
However, as with any cheap mount, the tightness won't last as the brass fingers start to wear down from the increased friction of being tighter.