Yashica 5cm 2.8 LTM test

I recently acquired one of the above and wanted to test it. I don't normally bother with comparison tests but, given the boredom level caused by the current lock down, I though it might fill an hour or two. I chose to compare it with my Jupiter 8 as it's the only other LTM lens I have worth mentioning.

The Yashica is the later, 5 element, type. Serial 91****.

The Jupiter is serial 58***** and is one of the earlier types but is reputed to be one of the better ones.

Lenses were attached to my Sony A7II.

Two full frame shots to start, both at f/2.8 (sorry about the brick of a test target - but it seems to work).

Yash 2,8 ff by Peter Robinson, on Flickr

Jup 2.8 ff by Peter Robinson, on Flickr

Immediate differences are the higher contrast of the Yashica, apparent better sharpness of the Yashica, yellowness of the Jupiter, the Yashica vignettes more and has a brighter edge to oof highlights.

Centre crops of same images

Yash 2.8 by Peter Robinson, on Flickr

Jup 2.8 by Peter Robinson, on Flickr

The Yashica does look sharper to me.

Corner crops of two more images at f/2.8 but focused on distant roof line.

Yash 2.8 corner by Peter Robinson, on Flickr

Jup 2.8 corner by Peter Robinson, on Flickr

The Yashica is sharper. The Jupiter has more chromatic aberration. Would be interesting to do test this on film.

Centre crop at f/22

Yash 22 by Peter Robinson, on Flickr

Jup 22 by Peter Robinson, on Flickr

I think the Jupiter takes it. The contrast of the Yashica seems to have fallen off and maybe the sharpness too a little.

I did several more comparisons at other apertures, which I won't bore you with. Generally the Yashica performed the best except at the smallest aperture.

The bright line around oof highlights of the Yashica is a concern because I generally don't like it. A couple more shots to show that again.

Yash 2.8 c by Peter Robinson, on Flickr

Jup 2.8 c by Peter Robinson, on Flickr

I definitely prefer the Jupiter for bokeh.

Edit: The more I looked at the last two pictures the more I thought there was something else going on. I wasn't sure I focused them correctly so shot them again. I then suspected curvature of field differences so shot a couple more pictures to test that and, sure enough, the Yashica has more curvature of field than the Jupiter. They both have some, but the Yashica is worse.

A very unscientific test. The Yashica, I think, out performs the Jupiter but I'm not sure I like it the best. I was hoping for a clear difference so I could sell one or the other. Now I'm not sure. Maybe a test on film will decide as that's what the lens will get used for.

Any comments or opinions welcome.

All the images and more on my flickr at www.flickr.com/photos/163570994@N07/albums/72157713954573273