Like most I misused the 35mm tubes also on a non CCTV camera, but adapted to a Canon M. weaknesses that occur there are indeed known in advance and, among other things wanted. However, with the lens can be many times more beautiful than focus with modern motor tubes, very smooth. Through lack of autofocus one is forced to spend more time with his recordings, which is quite positive. The Bokeh is very weird and funny, the basic focus I would call dangerous low.
The look is worth the money and you have a lot of fun with it.