The Zorki 10 was a modern-style 35mm rangefinder camera with a selenium light meter and shutter priority automatic exposure introduced in 1964.
When photographing sports or high-speed phenomena, shutter priority with short exposures can ensure that the motion is effectively frozen in the resulting image.
Older autofocus bodies will work with G lenses in shutter priority and program modes with full opened aperture.
The integrated lightmeter provides shutter priority and manual modes.
It featured a 40 mm f/1.7 lens and shutter priority automatic exposure in addition to manual controls, all in a compact package.
Offered from 1983 the R4s was a lower cost model with reduced features lacking shutter priority and program modes, however incorporating some improvements to the controls.
It allows the lens's aperture to be set by the body, and thus permits shutter priority and program auto exposure modes.
It supports Ricoh's own implementation of shutter priority and auto exposure modes, similar to the K mount but much simpler.
Newer G lenses without aperture rings only fully function under shutter priority and program modes.
Both aperture priority and shutter priority are available and it has a very accurate and simple to understand light meter.