Okay folks, I am not proud of this one butsince I would like to resolve the mystery, I will let you know what happened, if somebody can explain to me, it would be really appreciated. Here is the equipment involved: A Canon EOS 2000, Canon EOS A2, Canon 28-90mm II USM and a let's say "general brand" circular polarizing filter. I am using all this equipment for a while, except for the filter, and never had any major problem. Last wednesday, I had a shoot in a studio, with a nice model, I used my 28-90 all the time. First, I shooted a roll of fuji with my EOS 2000 then switch the lens on my EOS A2, I shooted 3 rolls of Kodak 100VS and I finished with a roll of Delta 100. It was not an important shoot, just a way to spend the afternoon, but here is what happened: Back home I souped the Delta 100 only one half of the picture is visible, yesterday I picked up the negs of the fuji, the same problem, now I do not know if I want to have my 3 Kodak 100VS processed. I am affraid of the result. The mistake I can see is my filter, that I let on the lens for all the shoot. But personally, I do not think a polarizing filter can totally mask haslf of the picture. What do you think ?