Steve Smith
Member
Rubber "O" rings won't work with the Canon EF Steve because the batteries in that particular camera need to make electrical contact all the way round, and. need to be of a conductive material like Copper.
So is the only option for the Canon, a machined adaptor?
I remember when my father put a silver cell in his Spotmatic, the meter moved the wrong way. Then we realised the polarity difference with the cells.
Steve.