Quote Originally Posted by srs5694
As to film format, 35mm was certainly used for still photography in the 1930s. (The earliest Leicas came out well before then.) My understanding is that 35mm became much more popular a couple decades later, though.

35mm was quite popular in the 30s, outside of America though. What made it less popular was the price. Leicas were quite expensive. Printing by enlargment, as required by the 35mm negative was also more expensive than contact printing.