Myopia. (front or backfocussing eyes
)It is possible to correct for astigmatism using an empty holder (supplied by Leica) and a lens made by an optician, but that has some complications. Firstly there are not many opticians that will supply a 10 mm lens. Secondly, if you correct for astigmatism it will only work when you hold the camera horizontal. As soon as you swing it 90 degrees, it corrects just the wrong way aggravating the problem. So for portrait you have to focus-and-turn