I'd like to offer my oppinion as an outsider but who loves the idea and looks forwad to this project, so pls take it as a positive contribution, not as an unwanted critique ... 😀
Honestly, there's so much hipocricy in this world, (including myself), it will be hard to leave the "reader" unbiased if there's written "leica" next to a photo, and "yashica" next to the other one... OTOH, a few words, a "little story", as taffer and others say above, would go well next to the picture. I personally enjoy books that do have a few words and not only the photos themselves. In its current format, looks really good; the text is not too long,not too bright,not too attention-drawing...complements well the image.
Off-topic: the cover: i also had the idea of using that t-shirt design with the rangefinder patch; it would clearly show that it's about photos with rangefinders, but it's not misleading. What I mean is, if there are cameras shown on the cover, one might think that the book is about rangefinder cameras and not pictures...and that would be a pity. On the other hand, if there's a collage of photos, that's no indication that there were rangefinders involved. And, it could look cluttered too.
Hope you don't mind for the above, and, good luck all🙂