The Leica M-2.0 Diopter Correction Lens provides an optimum eye-to-camera matching. The Leica Diopter Correction Lens feature combined viewfinder/rangefinder, which offers great focusing to the photographers. It helps the photographers in focusing even if they have any eye deficiency.You can compose images easily with the viewfinder in the Leica M-2.0 Diopter Correction LensThese Leica M Series Lenses are available in varied grades of plus and minus 0.5, 1, 1.5, 2 and 3 dioptersThe viewfinder in the Leica M should always be preset to -0.5For people wearing glasses of 1 diopter will need a +1.5 Leica Diopter Correction Lens