Their response will be something like, “Oh neat, where do you have your film developed?” A person less than familiar with film photography (most digital shooters) will very likely interpret this to mean the 35mm focal length. A modern film photographer will very likely interpret this to mean the 35mm film format.
It goes like this: Tell the person in question only that you are a “35mm shooter”. The purpose of this test is to identify a person as either a film photographer or digital photographer without directly asking them. Strangely enough, I’ve devised a social test involving these two facts.