I've just gotten a KW Patent Etui 9x12 (finally arrived, and it's in wonderful condition!). The one I have has the Schneider-Kreuznach Radionar 135 mm f/4.5, which (after a careful cleaning of the uncoated glass) seems extremely sharp to this long time, if casual, 35 mm and former 6x6 user -- but I've been told it's overshadowed by the Zeiss-Jena Tessar of the same length and ratio. Now, the lens I have, on the nice clean ground glass in my camera, will let me pick out individual chimney bricks and tree leaves at close to 100 feet when carefully focused -- and this with the lens wide open to give the brightest image. I know the image on the film would be better than my eye can distinguish in either case -- but how much difference would there really be between these two lenses? How would I tell, short of enlarging to far beyond 8x10 or using a microscope?