recently I took some portraits of my girlfriend and I was surprised to see all of them out of focus. My M8 works fine with summicron 50mm but the 90 is really off focus by some 10 to 20 cm. I then took some test shots with the sum 90 wide open, focusing on an object and then moving it back 5 cm at a time, everything else kept fixed. The problem is not apparent at a distance of 1,2 mt but the farther I go the larger the focus problem. At 3 mt distance I have to focus 15 cm before the object to have it sharp. I do not have a house large enough but I wonder what kind of error I get at 7 mt or infinity. Of course stepping down (f11) partially solves the problem but I also loose the very reason for using this lens for portraits. Anyone had same experience? Suggestion on who to trust for fixing it?
Thank you in advance
Sal