The Medis Rangefinder is an example of a very popular add-on accessory for many amateur photographers in the 1950s and 1960s. Although cameras with a built-in rangefinder were common at that time, many photographers had cameras with adjustable focus which didn't have a rangefinder, and this type of device was a simple and cheap way to help correctly measure the distance from the camera to a photo subject.
I remember my Dad had a rangefinder - probably a boots unit because he bought much of his photo equipment at boots[efn_note]We tend to think of Boots as a Pharmacy and Cosmetics shop these days, but in the 1960s they were a major photography shop. Until my Dad started doing his own processing, all our photos were processed at Boots[/efn_note], and used it with his Boots Beiretta viewfinder camera.
Photos of the Medis Rangefinder
In this gallery there are some photos of the Medis Rangefinder and some shots of the internal workings.
My Medis Rangefinder
I picked up my Medis Rangefinder when I recently bought a Braun Paxina 35 medium format camera, and the Medis was included with it - in fact, the inclusion of the rangefinder was a big reason for buying the Paxina.
Just to clarify how the rangefinder is used, there is a small eyepiece on the side of the unit where the distance wheel is. When you look through this eyepiece at a scene, you see two images. One is slightly yellow/green and the other a normal view.
When you turn the distance scale, the images move and when the two images are superimposed on each other and line up, you can read the distance that object is from you on the scale.
When I took it out of its leather case and tried it out, I found it was a bit out of calibration at infinity, and also the two images didn't line up vertically when I looked through the eyepiece to try it out. As it happens, both of these issues were easy to fix, as I'll describe below.
Fixing the Medis Rangefinder
The actual calibration of the unit at infinity was the simplest issue to fix. When I looked closely at the unit, I could see there is a knurled knob in the centre of the distance scale.
Turning this centre knob calibrates the unit, so all I needed to do was look at something on the horizon, set the scale to infinity, and then adjust the central wheel until the images in the eyepiece aligned. It was a little fiddly to do whilst holding the unit up to my eye, but a couple of attempts got it done.
To calibrate the vertical alignment, I needed to take the unit apart, which involved removing the two screws on the eyepiece side, and loosening four grub screws in the base. The pictures above show the inside of the unit.
What I found is that a small screw on the movable mirror arm adjusts the vertical positioning. It was sealed with a drop of varnish or something similar, so I put a drop of acetone on the screw to soften it, and then made small adjustments until the two images were aligned.
Once the screw was properly set, I used some Loctite 638 to re-seal the screw and re-assembled the unit.
Although I said at the start of this piece that the rangefinder was a useful accessory in the 1950s and 60s, it is still actually quite useful for us camera collectors even today. Anyone who wants to practice photography with a manual focus camera without any form of focus aid would find this tool helpful.
