I got this Vivitar 35ES rangefinder, rumored to be the same camera as the Minolta Hi-Matic S7 II, to see how hard it is to convert the lens which has Automatic aperture control to be used on the Sony A7. The aperture is not manually adjustable, obviously, but it is not controlled by a geared motor like modern lenses are. The aperture is still mechanical and I was able to link the aperture to the
ISO Shutter Speed ring on the lens. Not perfect as there is no indexing, but it allows the aperture to be controlled.
Tried it out today and I am very happy with how it renders images. More to come.
Vivitar 40mm f1.7 converted to Sony E-Mount
Delicious bokeh - Vivitar 40mm f1.7 & Sony A7