2 nifty fifties - Cosinon 50/1.7 and Yashica DS 50/1.9

[ManualFocus-G]

Hi all

I've been gradually selling off my grandfather's M42 collection over the past few weeks, and have the last two lenses to advertise. He said I can keep what I want from the collection (I've already snagged a couple of immaculate Soligors), so I might keep one of these too, for nostalgic reasons. Which one though?

I've just taken a couple of shots indoors, to test bokeh etc. Not exactly a solid test, and my camera always requires temperature adjustment when shot under artificial light (which is why the colours in some look a bit odd), so does anyone have any opinions on these lenses at all?

Here's the two together:





Quick tests all wide open

Cosinon



Yashica



Cosinon crop



Yashica crop



Cosinon



Yashica



Cosinon



Yashica



Cosinon crop



Yashica crop



Pros and cons

To me, the Yashica is sharper and has better bokeh. But it's auto only so will need modding

The Cosinon has an auto/manual switch but has what looks like very light hazing around the edge of the front element (probably not a prob on a crop sensor though...).

Are either of them Tomioka designs, would you think?

Any help would be much appreciated!

[casualcollector]

The Yashinon does seem to have a slight edge in sharpness. They may both be the same optical design from the same maker and may both have originated at Tomioka.

I've seen anecdotes about the Canon New FD 50mm f2 being identical to the 50mm f1.8. The F2 lens was allegedly made from elements that had edge defects that would have been rejected for use in the f1.8. The iris was limited to f2 so that the edge defects would have no optical effect.

The same may be true with your two lenses. The Cosinon being labeled f1.7 and the Yashinon as f1.9 for the above reason. Rather than scrap elements, they were assembled into lenses that gave buyers a less expensive alternative to the traditional Yashinon 50/1.7.

[ManualFocus-G]

Wow, great stuff! I never looked at it like that before. So I guess they could have both originally been destined to be 50/1.4s?

Many thanks for the info!

[casualcollector]

The elements probably originated as 50/1.7, 55/1.8 with the Yashinon labeled as 50/1.9 for whatever reasons. The glass for a 1.4 would be noticeably larger.

I sat down with five M42 normals and a cynic's eye one day and wrote this post. Please remember, this is all conjectural. 30 to 40 years after the fact, guessing is about all we can do until we can get some English speaking members of the industry on the forum!

http://forum.mflenses.com/m-42-normals-different-but-the-same-t10400,highlight,m42+normals.html