Looks like a grain of sand found its way on the pressure plate when you loaded that particular roll. No wonder judging by the quantity of dust your camera displays in the picture - and no offense intended. It happened to me a couple of times, and ever since I take the time to brush the film chamber on each roll change - if time allows. BTW, no MZ-S here, not yet.
Servus, Alin Petter wrote: PJ> A question for the MZ-S owners out there. PJ> Have you ever experienced scratches on the outside (not the emulsion PJ> side) of the film? PJ> I have and I'm suspecting my MZ-S is to blame. Could you please take a PJ> look at this picture and tell me what you think. PJ> http://w1.431.telia.com/~u43105651/ PJ> The scratch you see runs through the entire roll. On the other hand I PJ> took 10 rolls the same day this was taken and only this roll and one PJ> other were affected. The other affected roll had two or three negs PJ> scratched, not the entire roll. PJ> Any great ideas before I send it to the repair shop?

