I am starting to shoot with my leica M6 and elmar 90/f4. Maybe I am imagine stuff - but it seems like frame lines are showing much less than what I get on negative (around 10% less)? So far I have shoot only two TriX in leica, but I am quite sure of this. I always watch on edges of my frame since I always print full unformatted frame, (before I was usually shooting with nikon F3).
Frameines are generally imprecise with a Leica, and it gets worse with the long focal lenghts,
I the manual, Leica stated precisely the percentage difference at infinity between the actual image, and the framline. If I am correct the 90mm frames show only 85% of what is recorded.
As a rule of thumb, use the inside of the framelines at close focus, and the outside at infinity.
Thank you all for answers. Summicron 50 is on his way - with 50mm lens it will be more precise than with 90. I will do some test - to see exactly how it behaves with 50mm lens.