Quote Originally Posted by Jim Jones View Post
Long ago some lens apertures were marked in full stops from the largest aperture, as in the OP's example.
This is not the case here. It's a normal and typical european aperture scale from that period. It's the same scale as the modern, just different numbers.

There's no need to interpolate on it, since the shutter speeds are slower. If your exposure meter says aperture 8 and 1/125 use aperture 9 and 1/100 sec.