Two more images of the Alpa Reflex showing the unique rear viewfinder design of the early models.
With the camera back removed it's more obvious how close the rangefinder focus viewfinder (on the rewind side) and the framing viewfinder eyepieces are positioned to the film rails. So much that the camera back actually includes two openings to accomodate them. Of course it works well enough as each eyepiece features its own circular light trap around its circumference, but, seeing a camera back with two holes in it is still a little strange. The Prisma has the same arrangement, and differs mainly in its use of a pentaprism finder instead of a waist level. Reflex owners could (and did, in some cases, according to factory records) return their cameras to the Pignon works at Ballaigues for upgrading to Prisma specification.
You can just see through the rangefinder eyepiece that there are two rectangular, horizontal windows. The rangefinder image of the Reflex and Prisma Alpas is not superimposed into the focus viewfinder as is the case with most other rangefinders. The lower horizontal window provides a small view of the lower part of your scene. Very close to the top of this is the rangefinder window. The upper part of the scene is visible through it, but will move left/right within that window according to the focus distance of the lens (presumably via a pivoting mirror, I don't know the precise details of the installation yet). You can see the front of these windows in some of the photos I added in post 32, incidentally.
Thus, focusing with this system entails lining up the lower portion of an object in your scene with a decent edge on it (a tree, wall, whatever) with the lower window, and then adjusting the lens until the upper part of it aligns in the top window. The adjacent edges of the two windows are set very close together, but they don't quite meet, so Eg focusing on a person's eyes for portraiture is vaguely possible, but rather fiddly. And if you are a spectacle wearer like me, all of that just got a great deal harder to do, as there's minimal eye relief, making it that much harder to see much of both windows within the eyepiece readily, except for a portion of the centre. For subjects beyond ten feet or so of any size RF focusing isn't quite so bad, portraiture head shots, well, not so much use.
The reflex finders of either early hybrid camera are less than stellar. I suspect they'd improve somewhat if stripped and cleaned, but as found they are pretty grim, and I doubt they'd ever be good, let alone great. If I was using a Reflex or Prisma, I'd probably focus with the RF at middle distance (it's still faster, previous issues notwithstanding) but switch to the reflex focus system for setting the lens for close range images, head shots etc. Unless the absence of parallax at close range made the case for framing with the reflex finder overwhelming, as the main non-reflex finder is decently bright, regardless of how I focused the lens I'd be inclined to compose with it most of the time, anyway.
If this all sounds very mediocre, bear in mind the Reflex was in production during or immediately after the cessation of World War II. It is not a 1960s camera or even a 1950s one. I should take a look through the waist level of my pre-war Kine Exakta for a fair comparison, as it's the period the Reflex design harks from and would have been the main SLR competition. Rangefinder competitors, well, that's another matter. I don't do Leicas, but my pre-war Contax rangefinders absolutely cream it as far as ease of focus and finder brightness are concerned. I'd love to be able to strip one of the Alpas down, clean, adjust the optics and then try again, but sadly, that's not going to happen.
Inside the back, the serial number of the matching Alpa body is stamped near the pressure plate. At some point someone has also made some pencil notations on the back including its serial number and what might be 80 quid, 7 shillings and sixpence, perhaps? Maybe its second hand purchase price, it seems a bit cheap to be its list price when new, compared to period advertisements from the USA showing USD prices. The cost of some repairs, maybe? Australia converted to decimal currency in 1966, so if it was a reference to Aussie pounds, the notation was made over fifty years ago...