In 1975 Yashica introduced their first lenses for the new Contax/Yashica /CY) bayonet mount: Two wideangles (2.8/28mm, 2.8/35mm), two normal lenses (1.4/50mm, 1.7/50mm) and two tele lenses (2.8/135mm, 4/200mm). One yea later, in 1976, another seven lenses were added (3.5/21mm, 2.8/24mm, 1.2/55mm, 4/55mm Macro, 4/100mm Bellows and 5.6/300mm). While this in itself already was a rather useful lineup, the additionally available Carl Zeiss lenses (often also manufactured by Yashica) would fulfil demands even of demanding professionals.
"Yes Yashica's ML-lines are all designed and made by Tomioka optics except longer focal length lens and zooms (except ML 28-50/3.5). Those tele and zoom lenses are all made by Tokina so there is no use to spend lots of money to long focal length ML-lens. ML28-50/3.5 is a great lens, but large and heavy. It has a variable aperture to make the lens to have a constant speed f3.5, so at 28mm wide focal the lens apeture closes a bit to retain constant f3.5, this is relatively common feature at that era. Nikon made 25-50/4 (do not make a mistake as 24-50 af zoom) with same aperture mechanism, possibly Minolta's 24-50/4 zoom (might be f3.5, my memory is fading) too.
ML28/2.8 is better than Contax Distagon T* 28/2.8 IMHO, ML28 has uniformly sharp across entire frame and slightly less distortion. Although the centre shaepness is better for CZ28, this same thing can be said to ML35/2.8 against Contax Distagon T* 35/2.8. ML50/1.4 is far less distortion than Planar 50/1.4 and ML50's colour rendition is more normal ie. not too enhanced like Zeiss', I would say they are almost equal. For ML55/1.2 I think that it becomes a cult lens but after f1.4 both ML50/1.4 and ML55/1.2 are undistingushable to me, you do not have to spend money for 55/1.2.
Do not forget ML24/2.8 (which to me might have an aspheric front element), ML macros (F4 and F2.8 almost identical, also comparable to Ziess 60/2.8 macro lens, and better yet (but rare) ML100/3.5 you can call it a macro lens). I have never used ML16mm fisheye and of course telephoto lenses. " (koji fomr Hiroshima at mflenses.com)
https://pbase.com/kkawakami/mylens_yashicas