The Yashica/Contax mount is a bayonet design with a throat width of 48mm and flangeback of 45.5mm.
Zeiss lenses in the C/Y mount came in either AE or MM varieties. MM lenses were more recent, with a setting that allowed the camera to select the aperture as part of its autoexposure system, while the older AE lenses did not. There was often no difference between an older AE and a newer MM lens apart from this feature. Sometimes, the older AE lens may worth more on the used market because it may be a German-made example, while the newer lens may be Japanese-made, despite their optical formula and build quality being identical.
Zeiss lenses, on the whole, tend to have more even sharpness across the frame wide open - by comparison, Leica lenses, esp. the pre-ASPH designs, tend to be very sharp at the center and fall off substantially towards the corners.
Zeiss lenses, on average, have very high contrast and tend to give a magenta tinge (which can be a problem with portraits at sunset) while Leica tend to be more green.
Distagon 15/3.5
F-Distagon 16/2.8 - Noted for its unusually high speed.
Distagon 18/4
Distagon 21/2.8 - Noted for its unusual design and sharpness.
Distagon 25/2.8
Distagon 28/2
Distagon 28/2.8
Vario-Sonnar 28-70/3.5
Vario-Sonnar 28-85/3.3-4
Distagon 35/1.4
Distagon 35/2.8
PC-Distagon 35/2.8 - Noted for its tilt and shift capabilities.
Vario-Sonnar 35-70/3.4
Vario-Sonnar 35-135/3.3-4.5
Vario-Sonnar 40-80/3.5
Tessar 45/2.8 - Noted for its unusual “pancake” design, being very thin and lightweight.
Planar 50/1.7 - a plastic lens, but a very well made one;
Planar 50/1.4 - sharp; better bokeh than the f/1.7 but sharpness much the same;
Planar 55/1.2
Makro-Planar 60/2.8 - Offers a higher magnification ratio (1:1) than the other MM macro lenses.
Makro-Planar 60C/2.8
S-Planar 60/2.8 - Old type of Makro-Planar 60 mm f/2.8
Planar 85/1.2
Planar 85/1.4
Sonnar 85/2.8
Planar 100f/2
Makro-Planar 100C/2.8
Sonnar 135/2.8 - one of the best 135mm lenses
Planar 135/2
Zeiss does not offer much above 135. The long teles have a lot of chromatic fringing (no ED glass) with two exceptions - the 300 APO-Tessar f/2.8 ($US13,000) and the APO-Vario-Sonnar 100-300 f/4.5-5.6 zoom
Sonnar 180/2.8
Apo-Sonnar 200/2 - Noted for its unusually high speed and an iris with extra blades for smoother bokeh and rounder highlights, designed for portrait and fashion work. It came with a set of drop-in filters.
Tele-Tessar 200/3.5
Tele-Tessar 200/4.0
Vario-Sonnar 70-210/3.5 AE
Vario-Sonnar 80-200/4
Tele-Apotessar 300/2.8 - Noted for its sharpness and stratospheric price.
Tele-Tessar 300/4.0
Vario-Sonnar 100-300/4-5.6
Mirotar 500/4.5
Mirotar 500/8
Tele-Apotessar 600/4 AE
Mirotar 1000/5.6 AE
Mutar I 2x teleconverter
Mutar II 2x teleconverter of high quality, designed to mate with long telephotos.
Mutar III 1.4x teleconverter