Cheers I had found it myself anyway. Wow. It seems an issue that many people are able to reproduce. For the benefit of others that do not want to read all the other threads on the subject I will try to summarize below on the EM5 vs 20mm banding issue.
The banding ONLY occurs with the Panasonic 20mm f/1.7 and ONLY on the new Olympus EM5.
On some of the examples posted it is very obvious. (Banding = Horizontal lines accross the screen). What a shame for EM5 owners, and in fact the future resale price of fellow 20mm lens owners perhaps?
Some people have posted interesting hypotheses based on simulation tests. The whole thing is very interesting. Initially people were going down the road of the conditions (fluorescent lighting) being the culprit. But now we have evidence suggesting that it is some kind of electrical interferance possibly based on the 20mm acting as some kind of arial to amplify certain radio frequencies (mobile phones etc). One person tested with the 20mm mounted to the EM5 body, but with the contact points taped up which should have meant that no electrical connection was being made to it. The very nature of the 20mm being "grounded" against the body could allow the issue to present itself. Perhaps the internal AF motor (is there a magnet inside?) or construction of the lens not being as shielded is causing it. People have tried various other lenses on the EM5 and could not reproduce the banding issue. It is limited to the 20mm prime. Surely a firmware fix for the EM5 is unlikely to address this kind of issue?
I wonder if Olympus have even been made aware of the issue yet. Forum users typically like to moan about problems, and often forget to inform the manufacturers.
The banding ONLY occurs with the Panasonic 20mm f/1.7 and ONLY on the new Olympus EM5.
On some of the examples posted it is very obvious. (Banding = Horizontal lines accross the screen). What a shame for EM5 owners, and in fact the future resale price of fellow 20mm lens owners perhaps?
Some people have posted interesting hypotheses based on simulation tests. The whole thing is very interesting. Initially people were going down the road of the conditions (fluorescent lighting) being the culprit. But now we have evidence suggesting that it is some kind of electrical interferance possibly based on the 20mm acting as some kind of arial to amplify certain radio frequencies (mobile phones etc). One person tested with the 20mm mounted to the EM5 body, but with the contact points taped up which should have meant that no electrical connection was being made to it. The very nature of the 20mm being "grounded" against the body could allow the issue to present itself. Perhaps the internal AF motor (is there a magnet inside?) or construction of the lens not being as shielded is causing it. People have tried various other lenses on the EM5 and could not reproduce the banding issue. It is limited to the 20mm prime. Surely a firmware fix for the EM5 is unlikely to address this kind of issue?
I wonder if Olympus have even been made aware of the issue yet. Forum users typically like to moan about problems, and often forget to inform the manufacturers.
. When 3 in 1 oil didn't work I gave up! 
with cashback they end up a little over £150.
