Leitz Summar 120/4,5

Once Ernst Leitz Wetzler GmbH. produced lenses for DPE purpose and Summar 120/4,5 at hand is one of them, probably DHP(Deuches Heides Patent) period. I put this one on Asahi Pentax helicoid extension tube in order to set on Canon EOS Digital image format 10s years ago, establishing infinity lens back position, I have been using it as one of an ordinary use lens not for special close up purpose, unusual "Boke" taste was there. Though I knew the special use for this from the Web site information, I have never checked the physical performance if used as a close up lens, not for 2 dimensional as it had been originally designed but for 3 dimensional objects?
As a matter for surprising result, I don't find out any words to deny the excellent performance as a macro lens, thanks to relatively longer focus length 120mm, I can keep a distance when shot 2/3 magnification in good situation that is very convenient for enough lighting exposure value. Close up shooting field must be much more interesting than before, especially more than 1/1 magnification, probably, unpredictable difficulty must be waiting for me, lighting methods with any special reflectors, shooting angle, camera and lens fixation, noisy lighting cut by adjustable burn door and so on, there exist an interest and curiosity to ride over it come in a  new different world?