The Contax RTS heralded the revival of the Carl Zeiss lens brand. It was unveiled at Photokina 1974 (entering the French market in December 1975), and its development was the result of collaboration between Carl Zeiss, Yashica for the electronics, and Porsche for the design of the body (it remains the only Contax model designed by Porsche).

This camera is fully electronic with aperture-priority exposure mode and can be fully operated manually.

The RTS introduced several advanced features, including a 1/2000th second shutter speed, exposure compensation, a small lever to raise the mirror (for macrophotography), an electromagnetic shutter release, two motor options (a 5 frames per second motor and a more modest 2 frames per second Winder), interchangeable focusing screens, and LED display of shutter speeds in automatic mode.

The shutter release is so sensitive that, for safety reasons, the light meter button was placed on the front face, requiring some adjustment (one might initially think the camera is malfunctioning when lightly pressing the shutter release for exposure metering and nothing happens!).

It is a high-performance, rugged, and aesthetically pleasing camera.

The RTS paved the way for a series of surprising models with increasingly elegant and ingenious technical innovations (such as the Contax 159 MM with its shutter priority mode or the Contax AX, allowing MF lenses to work in AF!).

Exposure metering is handled by a unique silicon cell, measuring at the center of the focusing screen and weighted.

The bayonet mount was jointly developed by Zeiss and Yashica.

The film rewind crank is special because it is concentric with the speed dial barrel. Therefore, it cannot turn during film advance to prevent unintentional speed changes. Yashica developed a special system that prevents it from turning during film advance, and there is an index to show correct film advancement.

Very elaborate and meticulously crafted, this camera employs pneumatic dampers to minimize vibrations during mirror or shutter movement.

It is part of a comprehensive photographic system, integrating numerous excellent Zeiss lenses, motors, adapters for microscopes, flashes, tripods, etc.

Alongside this advanced body, Yashica developed a more "rustic" camera capable of using Zeiss lenses, the Yashica FX-1.