It seems to me that vintage glass is causing the pink/green LOCAS. If you stop to think, there is a lot of glass surfaces (some uncoated) causing aberrations. Here in my country (Brazil) do not have snow, so I do not know the size of snow crystals. However, as compared know of a photographer who made a Gadgety to photograph the grains of sand on the beach, and he discovered colors, and shapes that never imagined seeing a seemingly monochromatic sand. Even invisible to the naked eye molluscs. The equipment of him consists in: 5Dmark ii + 180mm L + extension tube crafted with PVC piping (30 cm) + support for camera and flash with adjustable crank gears. As it is necessary to bayonet adapters, can avail to use the bayonets of cheap extension tubes and macro lenses like Nikon 200mm F4.