>>4323775Classical film cameras really only a shutter speed knob.
There was no need for an aperture knob on the camera since the lens already had a ring to control it.
Separate controls for shutter and aperture only happened with auto-exposure cameras, and there was no precedent for where to put them since the need for them was new.
Similarly to change the ISO you had to actually put in different film! The ISO setting on the camera was really just to tell it what speed of film you'd already put it. On manual exposure cameras the ISO only mattered for the meter, and cameras that didn't have a built in meter also dind't have any ISO setting. The ones that did, it was often combined on the same knob as the shutter speed or built into the rewind post or something, since it wasn't something you twiddled on every shot and access to it didn't need to be fast.
"Real" ISO control didn't become a thing until digital, and brought up the same question of where to put it.
