How would Yashica M lenses compare with modern Canon lenses in terms of image quality

[saqib]

I’ve come across an interesting offer where I can get the following for just $90 bucks:

Yashica ML 28mm f2.8
Yashica 50mm f1.9
Yashica 135mm f2.8
Yashica to Canon EOS Adapter

Now let’s assume that the wear and tear on these lenses is minimal, i.e. there’s no lens separation and fungi, and very few scratches. Do you think it’s a good deal? Ok maybe it’s the wrong question.

What sort of problems can I face using these lenses? Two problems would be, I reckon, the lack of auto-focus and the inability of the camera to control the aperture.

What else? Does the use of adaptor reduce the quality of the image? What effect does the adaptor usage have in general?

How would the Yashicas 50mm 1.9 compare against the Canon’s 50mm 1.8? Would there be a great difference in quality of images taken by these two, minor or no difference at all?

Remember the Canon 50mm cost about $100 bucks while all these lenses combined are on offer for less than that.

Any other suggestions?

[sassan]

Not sure after 6 months you are still seeking answer to your question but then in the interest of anyone that might be having a similar question let me answer yours:
Old vs New: Any new DSLR camera lens is built, shaped, cut and coated to optimal needs of its digital companion sensor and camera, very different from that of Film camera lenses so newer lenses will work better on DSLRs. This doesn’t mean that old lenses are of lower quality. They were built for different needs yet can still give good result if you know how to use them.

Adapter: Any lens that is used with an adapter having a corrective tiny glass within adapter to allow infinity focus significantly reduces IQ (Image Quality) adds unwanted Chromatic aberration and degraded the final image. Certain older brands like Canon or Minolta need these optical correction or can’t focus to infinity. But some camera brands don’t need glass in adapter (Also all old lenses can be used for near field photography / macro with no glass adapter). IQ is usual and without any loss this way.

Yashica Lenses: To answer you last question, Yashica lenses are among the best old world lenses. My friend from this forum Duncan (RIP) would object this and says Pentax is the best but then Yashica and Pentax merged at one point and Yashica later on teamed with Zeiss that is Crème de la Crème of all optical world.
Older Yashica lenses, called DSB had only one layer coating and known for lower IQ (Compare to other Yashica lenses, not in general). The USA version of same lenses with identical lower quality were marketed under YUS name. Later on the improved versions showed up with Multi Layer coating so called ML. This was again replaced in later years with MC (Multi coated) with no significant farther better quality as compare with ML that are both equally good. But the most desirable Yashica lenses are the older 42mm screw lenses under the name DX. These are harder to find and the most popular among the collectors, know for very high quality similar to Zeiss.
Bottom line: You are the only one who can decide for yourself as to what to buy. If we go by the eg you quote here; to compare 50mm ML Yas with Nifty Fifty F1.8 Canon, the very first moment you hold one in your hand, you will be impressed by the metal built quality of Old Yas and its tank quality that has stood the test of time as opposed to cheap plastic quality of Canon that features light year advanced technology incorporated. You can take excellent images with old Yashica lenses or for that matter most old good quality lenses, if you know what you're doing; in handling of manual focus, non-electrically coupled lens etc. You will have a lot more ease when using a new lens with much less practice or knowledge needed, in short more convenience to produce a good quality still image. But you can’t go wrong in either way.
I am personally using my EOS-M camera body with a non-optical adapter when taking picture with my Yashica DX 50mm F1.7 with excellent image quality that is Razor sharp and has very good color tone. Also get excellent pictures with that tiny 22mm Canon STM lens that camer with the body, totally happy with the result either way.

[hemdean]

Back on the early 70's I did some comparison optical tests between the 50mm 1.7 Yashinon ds and the 55mm 1.8 smc Takumar. The Takumar gave an excellent, balanced performnce across the frame however the centre performance of the Yashinon was quite exceptional though the outer field was inferior to the Takumar's but till very good. This was typical of early Japanese lenses and was a deliberate design trade off as at the time lens design possibilities were much more limited than today. The early Zeiss 50mm 1.4 was similarly afflicted. That said, using these lenses with small digital sensors makes an ideal combination! I would give the economy 1.9 and old DX's a miss there is better value to be had.