Created through the combination of Porsche design skills, Yashica electronics technology and Carl Zeiss precision optics, the Contax Real Time System (RTS) was the result of a rare combination of talents. Real Time photography was a concept created to meet the needs of the working professional and advanced amateur as well. For overview of various models of Contax cameras, please refer to the History of Contax.
The Zeiss interchangeable lenses with Contax/Yashica mount covered the focal length range from 15 to 1000mm, all providing extra-high speed for most convenient application even in adverse light situations. All these lenses offered to the photographer the traditional Zeiss quality and performance standards. The latest developments were incorporated, including the Zeiss T* multi-layer anti-reflection coating, the use of aspherics and floating lens elements. Zeiss T* lenses were striking examples of the complete balancing of optical factors such as resolution and contrast, uniform illumination across the entire image field, high light transmission, freedom from distortion and optimum color correction. Image quality was also superb at all apertures.
Yashica lenses featured advanced design devised through application of the most up-to-date know-how in the field of optics combined with the most sophisticated computer programming. Coupled with their original superb performance, all excepting the reflex and DSB lenses featured multi-layer anti-reflection coating which eliminated harmful reflections and assured maximum light transmission.
Yashica MC was a line of lenses compatible with Yashica Multi Program series cameras. MC means "meter-coupled", and not "multi-coated". Nevertheless, these MC lenses were also multi-coated.
YUS (stands for Yashica US) was a budget line of single-coated Yashica lenses that was sold only in the North American market and consisted of only three models: 28/2.8 (⌀52, ⌀55 and ⌀58), 135/2.8 (⌀55 I, ⌀55 II and ⌀58) and 75-150/3.9.