M50mm F1.1lens optics contains 7 elements in 6 groups and is based on Sonnar formula. Itincludes two high refraction optical elements of index 1.9 to improve picturequality and lens portability. R&D process involved analysis of fieldcurvature and image astigmatism influence on image and out of focus areas.Numerous corrections and improvements made to receive great image performance.Using lens wide open at F1.1 aperture delivers pleasant bokeh. Stopped to F1.4,it improves sharpness while keeping smooth out-of-focus areas. Repetitivecorrections of spherical and chromatic aberration lead to very well controlledligh spots shape, and good contrast and sharpness in focus area of this largeaperture lens.