Summar 12cm/4.5

One of my favorite Macro lens is Leitz old Summar 12cm/4,5, I have an experience to win a prize in some contest utilizing this marvelous one while the silver salt period of time. In relatively iris opened condition, this one performs ultimately marvelous expression on the transparencies, on the other hand, the performance when iris closed to 48 circumstance exceeds the sharpness of Nikon 105/2.8 Macro Nikkor, smaller and tiny looks as it does, the potentials of this ancient old Leitz Macro specialized lens is unpredictable.
Several adapter rings were matched with lens threads to establish infinity length in combinations with Asahi Pentax Helicoid adapter ring. Hood is specially hand made with noise killer anti-reflector rings when used on 6 by 4.5 Mamiya SLR analogue body while silver salt period.
Much more using experiences are required for me to master this one even after 25 years from obtaining. The use of this lens on small Leica format 36 by 24 might be basically out of point, because the image circle is far larger than 6 by 7 format, this opinion is based on the actual use on Asahi Pentax 67.