I have an Agfa Isolette. It's a great camera but with the guess focusing and no metering it's a bit hard to shoot. I'm fine as long as I'm outside where sunny 16 and hyperfocal focusing works, but inside is a bit harder both because I have to guess exposure and the larger apertures makes actually focusing much harder for me. So either I get exposure right but focus is wrong, or vice versa. I've come to realize there is such a thing as an accessory rangefinder that fits on an accessory shoe of a camera, that would read out the distance in feet, so I could transfer it to the camera lens. This would be amazing in certain situations. So, do these kind of accessory rangefinders work pretty well, and are they available pretty cheaply?