A Canon 7 or Canon P would both be good choices. They offer larger viewfinders than many of the Barnack type cameras or Soviet copies. The Canon rangefinder cameras are relatively inexpensive, and they are usually fitted with very good quality 50mm lenses. 35mm and 28mm lenses were also produced, or you can use LTM lenses made by Leica, Voigtlander, Nicca, etc. You can easily find a clean Canon 7 or Canon P with a 50mm lens for less than $500