Yesterday I found for £10 in a charity shop the Kodak version of the agfa in fair condition, every thing works it just needs a good clean. And yes I bought it worse case the charity got £10.
Glad you touched on all the garden varieties of simple woes these old simple cameras might exhibit over time. Not surprisingly, the Yashica was the winner since the true TLR where often the choices of most professional photographers before the advent of dedicated medium-format for the advanced user. Not sure why the Isoletta from Agfa is giving you lost contrast unless the shutter timing is off. Agra/Ansco used a heavier lubricant than many other makers, which with time will congeal somewhat. A thorough CLA may well sort it sufficiently to get your your clarity & contrast to return. Enough said on the Kodak, box & folding camera's since both are nearing 100 years of age, and few would spend the cash to ever restore the springs or service the ball-bearing mechanisms with so little to be gained, as most use a basic meniscus lens arrangement.
I have a Flexaret (TLR) ca 50/60 built, you have to plan time for explaining people what camera you are using 😉 I also noticed that using a Twin Lens Reflex on the street doesn't bother people much less than other cameras, I think because they don't realise that you look through the viewer from above! So a good question to ask yourself is what do you want to do with the camera? Incidentally: I came to making photos with old cameras through videos like this one😉
The "slightly over engineered door" on the Agfa? You can't rely on the red window to protect the film as today's films have a different chemistry and the backing paper is thinner. This is an even bigger problem on the two older Kodaks; electrician's black insulating tape is your friend. Very informative though, sorry part two never got made.
Makes you wonder why the manufacturers keep printing the numbers on the backing paper. I agree that it's a good idea to cover the window between winding.
