I have been thinking about this for some time now and wonder if anybody else is doing as I have done. I have a few older rangefinders ie. Konica Auto S2 and Yashicia that orignally used mercury batteries which are no longer available. In the absence of these batteries I'm using 1.5v and 6v batteries and biasing the ASA setting to compensate for the larger voltage. I have read that using the higher voltage batteries will cause the auto function to over expose the film. Has anybody done any scientific research on this matter, or just plain experimented as I have done.