ASA film speed is a numerical value describing the light sensitivity of the film.

Exposure value is INDEPENDENT of film speed and expresses various combinations of shutter speed and aperture as a single numerical value.

The Kodak Pony has its aperture marked in EV as a “simplification” for easier amateur use. At least that was the idea. It works on the Pony because it only has a single fixed shutter speed. With a camera with a variety of different shutter speeds, the idea of marking the aperture with EV numbers is impractical.

Once you select a particular film, you have set the film speed. Now both the film speed (its sensitivity to light) and the shutter speed (1/60 second) are fixed. Each data card for the Pony was made to correspond to the film speed of a common Kodak film in use at the time the camera was made.

All the user had to do was read the sky lighting conditions on the card to find the corresponding EV and set that value on the aperture ring.