I already had this model of 77mm diameter filter for my Canon ultra wide-angle (equivalent to 16mm in 24x36) and did not have any vignetting problem (filter quality is excellent, very fine horse, it is often more sold much cheaper than its normal price) - which was not the case for the Lumix which was for it ... This is why I have made it 4 stars. So I returned and Amazon was very professional as was his habit.
