Mercury II with Flash
To use a Hot Shoe
The photo below is an Univex Mercury I am using now. I made a contact pin of old Canon strobe flash to move a bit rear in order to touch pin to the Mercury's hot terminal on the center shoe. It works good and is able to take flash shots at only 1/20 sec of lowest speeds.
A hood on the lens is home made by 35mm film case and left beside is a Walz range finder.
Mercury II Tricor 35mm F3.5 f8 1/20sec Just tested by flash, Canolite D(GN=12)