My early postwar super ikonta bx (f2.8 tessar t, front cell focusing) is critically sharp. Its comperable to a Rollei tessar. Had a prewar uncoated version that was sharp too, although much lower in contrast due to the lack of coating. I also once had a very sharp contaflex iii (45 mm f2.8 tessar t) that was also front cell focusing. I suspect the cheaper build of the super ikonta iv is more to blame than the optical formula.