The viewfinder has a couple of grid markings in it, but I am not srue that they signifiy where the panaramic mask is. I am sure that you could do a test roll and figure it out rather quickly. It is a great lens though. I recommend it highly. It is more useful than a normal 21mm equivalent lens since the distortion is so low and there is so much negative in a 6x7 camera. It is actually rather hard to tell the difference between this lens and the others unless you know how far away you were from the subject.