Auto Yashinon 5cm f/2

<p>Hello CMC.</p>

<p>I have a question regarding the Yashinon 5cm f/2 lens. A while back I found a near mint copy of one attached to a Yashica J3 at a local thrift store. Now being a sucker for Yashica (Tomioka) lenses I just had to add this to my collection. I have recently pulled it back out of the bag to use it on my Sony A7 and I am simply blown away by the results.</p>

<p>The lens is very sharp wide open. It exhibts little to no CA while also exhibiting the Yashica swirly bokeh I am fond of. And the build quality is simply superb. It is small and jewel like, more reminiscent of an old rangefinder lens then any made for an SLR. It is prone to flare due to the primitive coatings used (we are talking early 1960's here) but if used smartly then much of this can be avoided. Overall it is a wonderful little lens.</p>

<p>My question is does anyone know or have any old periodicals that might have some technical data for the lens? I am mainly looking for groups and elements info. I found one resource online that said it was a Tessar design. That surprised me at first but then considering the size of the thing I suppose it could easily be a simple 4 lens/3 groups in the classic style. For some reason I was just assuming it would be some type of double gauss design, as most of my other fast fifties are.</p>

<p>I would greatly appreciate any illumination on this lens that the CMC forum might have. I know it is almost certainly made by Tomioka, since they pretty much made all of Yashica's lenses for them. And this lens is identical to one that is labled Tominon. I mean 100% indentical. It is also about 99% identical to the Auto Takumar 5cm (or 5.5cm) f/2. That one has ten aperture blades tho, whereas the Tomioka badged model and Yashinon model both have only 6.</p>

<p>Here are a couple of shots I made on a field trip this weekend. Sorry that they are on the Sony A7 instead of the Penta, but my workflow has become completely digital. I do still shoot with nothing but old film lenses though, and for that the A7 is a perfect tool.</p>

<p><em>on the fence about things</em><br>

<img src="https://farm4.staticflickr.com/3945/14948124244_d78015db37_c.jpg" alt="" width="800" height="534" /></p>

<p><em>under the trees</em><br>

<em><img src="https://farm4.staticflickr.com/3936/15383244000_1cc5558841_c.jpg" alt="" width="534" height="800" /></em></p>

<p>I think you are right about it being a double gauss design of some flavor, David. I had one on a Yashica J. Nice compact lens. <a href="https://www.flickr.com/photos/kuuan/collections/72157632455712332/">THIS</a> fellow did some tests with it and compared it to some other vintage normal lenses that you might find of interest (on a 5n though).</p>

<p>You're right, <strong>David</strong>, it's a great little lens, though rather shrouded in mystery. Apparently it was considered a little "slow" at f/2 and Yashica dropped it in favour of f/1.9 and f/1.7 designs. As if it really mattered... According to the Draft Lens List on the fine Yashica Boards net. site, the construction is 6 elements in 5 groups, so it obviously doesn't lack sophistication. Subsequent versions apparently changed to a 6/4 formula. As for the similarity between this and the equivalent Takumar, there is certainly a strange and wondrous similarity... I post a pic below. I'd like more information, too, if some erudite member can supply it. Great portraits, BTW...</p><div></div>

<p>You probably will not find any lenses with f/2 and beyond following the Tessar design. Tessar designs sometimes are really excellent - as far as the lens power is not pushed too much. <br>

Most lenses with f/2 and beyond from the 60s on followed the double Gaussian design. Another approach was the Sonnar design, which can be considered as a "modified triplet". The Tessar is also a "modified triplet" (although it was NOT designed based on a triplet lens), so there is a certain relationship between Sonnar-type and Tessar-type designs. </p>

<p>Louis, looks like you are right as the consensus seems to be that a Tessar is a no go here. Thank you for that link, there is some interesting viewing there. I know its hard to really compare lenses like that gentleman did due to sample variation and the difficulty in keeping the test criteria accurate, but he did a really good job. His copy of the Yashinon preformed decently, but I was very impressed with the little 50/1.8 Zuiko. He has a sharp copy of that lens to be sure.</p>

<p>Rick, thanks to you as well for the heads up on the Yashica Board. I wasnt aware of that. And you're right, it really is a sophisticated little lens. Makes you wonder why they cant make simple, small lenses like this today for all the new mirrorless cameras that on the market. I guess that means these old lenses are just all the more special because of that. I am very much intrigued though about the possible connection between the Yash and the Takumar. Did Tomioka make some of the original Pentax lenses as well? They were a large 3rd party supplier so it is entirely possible I suppose. I really thought that Pentax made all their own lenses, but back in the early days it might have been easier to just purchase an existing design to fill holes in the lens lineup. Maybe that is what happened here.</p>

<p>The Tomioka Tominon C. 5cm f/2 is for sure the exact same lens, as can be seen<br>

here. http://www.kevincameras.com/gallery/v/m_42_len/tomioka/50_2/392070/<br>

There are several variations between the color of individual parts like the focus ring or aperture ring, but it is the exact same lens with same engravings. I would love to pick up one of these old Tominons but they fetch ridiculous prices on the auction site, with asking prices starting around 600. Think I will just keep my little Yashinon and be happy. :)</p>

<p>Winfried, I didnt think about the speed factoring into whether the lens might be a Tessar, but you are entirely right. Also, in retrospect, the out of focus area from this lens is really nothing like the other Tessars I have owned. So that should have been a clue as well. Thanks for the input.</p>

<p><strong>David</strong>, I can only suggest you don't start delving into the origins of Japanese glass of this era, as it can lead to dementia... All very complex and convoluted. Tomioka was a major player in lens manufacture, being acquired by Yashica fairly early in the piece, but I've never seen confirmation that Tomioka manufactured lenses for Pentax, though hints of an association crop up now and then.</p>

<p>The advent of anti-reflective lens coating post WWII reduced the advantage of the tessar and sonnar designs , which featured fewer air to glass surfaces and therefore an advantage in contrast compared to the double gauss design. With the new lens coatings significantly improving contrast, the double gauss planar design came back in the form of the Carl Zeiss Jena Biotar 58/2 of the late forties. It was a revolutionary lens at the time with a significant impact.<br>

Most of the Japanese and German 5 to 5.8cm lenses of the 50's and 60's appear to be inspired if not directly copied from it.<br>

Just my personal opinion. But then I have serviced all of the known Yashica "normal" f1.7/f2 lenses from the J series cameras up through the F* series, and also several varieties of 58mm Biotars.<br>

I have also used several of them in M42 including Yashicas, Biotars, and Pancolars on Sony Alphas with pleasing results.<br>

They are all contrasty (for whatever their time period) and sharp, but the bokeh is quite variable!</p>

<p> </p>

Thanks for everybody's contribution. Interesting Thread! There was a Zeiss C/'Y 35mm 1.4.Tessar wasn't

there? Raison d'etre? a very fast semi wide I guess!