Powering the flash coupler L

<p>Since the mercury batteries are no longer available, what batteries can I use to power the flash coupler L?</p>

<p>I have one of these. Any battery which has voltage which is even close and which fits will work. My recollection is that it took a 675 size battery. I tried MS76 batteries and they worked. The battery you use in a Coupler L does not trigger anything or affect the light meter. It simply illuminates the right side of the finder. Typically if the ambient light is so low that the finder needs illumination then you don't have enought light to shoot without flash anyway. You flash will usually have its own illuminated dial and that should be adequate. It would be helpful if you could see the aperture numbers through the finder but the F-1/F-1n does not offer this feature. On very sunny days I sometimes have to push my hat back so the meter needle has better illumination. </p>

<p>The Flash Coupler L was designed to take two mercury batteries, one H-D type (also known as the PX625 or EPX625) and one H-P type (also known as the PX-1 or MR50). Here's a link to the instructions for the Flash Coupler L:</p>

<p>http://web.archive.org/web/20070609054003/www.canonfd.com/flashcouplerl/index.html</p>

<p>There are 1.5v alkaline and 1.4v zinc-air equivalents for the original mercury batteries. Alkaline PX625s should be easy to find. Zinc air PX625s include the Wein PX625 and the Exell Z625PX. The H-P replacements appear under different manufacturer codes - LR50, PX1A, PC1A, EPX1, A1PX, etc.</p>

<p>I must have used an A625. I keep those around for use in my EF.</p>

<p>Use anything that gives 1.5 volts. I threw in a watch battery and some aluminum foil. It works!</p>