I designed an adaptor to fit a Watameter II rangefinder to my old Ensign Ranger I. I absolutely love this camera, but I've only been able to use it at infinity since there is no way to focus it other than guessing. Adding this rangefinder allows for the camera to be properly focused.

This adaptor sits underneath the folding frame finder. It will likely also fit on the Ensign Ranger II and with other models of Watameter, though I haven't tested this. I've included the CAD files to allow you to adapt the design to your specific camera.

I printed it in PETG and the resulting fit is stiff. I recommend pushing the rangefinder in and out of the adaptor to loosen it up a bit before putting it on the camera. I wanted a reasonably tight fit in order to stop the rangefinder falling off in use.