http://www.cameraquest.com/voigt4m4aintro.htm

The Voigtlander R4M and R4A are the only production 35mm rangefinder cameras ever made with built in parallax projected framelines for 21, 25, 28, 35, and 50mm lenses.

The new R4 series offer a combined rangefinder/viewfinder at .52x magnification with user selectable 21/35, 28, and 25/50 parallax corrected brightline frameline combinations. These are high eye point viewfinders.

The R4M is a mechanical shutter camera and the shutter works without batteries. The TTL meter requires batteries and It has a LED metering display along the bottom of the viewfinder, displaying exposure information in .5 EV values.

The R4A is an electronic shutter camera which offers metered manual or aperture priority exposure. Like most other electronic shutter cameras, dead batteries mean a dead camera.

These cameras take 2 LR44 alkaline or 2 SR44 silver oxide Batteries. I use the SR44 silver oxide Batteries in mine and I carry spares.