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Mamiya Sekor 50 mm f/3.5 enlarging lens
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PostPosted: Wed Oct 11, 2023 8:17 am    Post subject: Mamiya Sekor 50 mm f/3.5 enlarging lens Reply with quote
Until recently I doubted its existence because while I knew about the ENLA-Units and the (likely) Mamiya-made lenses in there, I've never stumbled upon a Mamiya enlarging lens. But here it is:

Rocked to Se kor by simple.joy, on Flickr

Of course it's still possible that it was used for some other purpose (repro-work or as a bellows lens) but it features the common M39 thread and a beautiful (or ugly, depending on your perception) rounded square aperture shape, similar to a couple of other enlarging lenses in that focal length.

Have you ever seen this lens? It doesn't appear to be anything special, mind you. The specs and aperture shape would suggest that it's a kind of budget lens, but it's not bad at all, judging from a couple of first test shots. I'm pretty sure it's a Tessar design, so it doesn't seem to have any resemblence with the (specs-wise) identical Mamiya Sekor E Macro 50 mm f/3.5 Stephan has some information on here:
http://www.artaphot.ch/mamiya/e-ef-lenses/164-mamiya-sekor-e-ef-lenses/578-mamiya-sekor-e-50mm-f35-macro.

Here are a couple of shots though:

Capturing the essence by simple.joy, on Flickr

Get with the times! by simple.joy, on Flickr

Colorful ex-berry-ends by simple.joy, on Flickr

Pretty sure I'm going to have some fun with this one!


PostPosted: Wed Oct 11, 2023 10:26 am    Post subject: Reply with quote
Never heard of this lens, but the results look good!


PostPosted: Wed Oct 11, 2023 12:05 pm    Post subject: Re: Mamiya Sekor 50 mm f/3.5 enlarging lens Reply with quote
simple.joy wrote:
Until recently I doubted its existence because while I knew about the ENLA-Units and the (likely) Mamiya-made lenses in there, I've never stumbled upon a Mamiya enlarging lens. But here it is:
...

I'm pretty sure it's a Tessar design, so it doesn't seem to have any resemblence with the (specs-wise) identical Mamiya Sekor E Macro 50 mm f/3.5


You can check that by carefully counting the reflexes before and after the aperture (e. g. using a small LED light in an otherwise dark room). The Sekor CS and E 3.5/50mm Macro lens should have four reflexes in front, and five reflexes at the back side. Interestingly, the Mamiya Sekor CS/E 3.5/50 Macro is a "reversed Xenotar" type lens, something I hadn't noticed up to now:

http://www.artaphot.ch/mamiya/e-ef-lenses/164-mamiya-sekor-e-ef-lenses/578-mamiya-sekor-e-50mm-f35-macro

Your Mamiya 3.5/50mm, if it is a Tessar type, should have four reflexes in front as well, but only three on the back side.

S


PostPosted: Wed Oct 11, 2023 2:44 pm    Post subject: Re: Mamiya Sekor 50 mm f/3.5 enlarging lens Reply with quote
stevemark wrote:


You can check that by carefully counting the reflexes before and after the aperture (e. g. using a small LED light in an otherwise dark room). The Sekor CS and E 3.5/50mm Macro lens should have four reflexes in front, and five reflexes at the back side. Interestingly, the Mamiya Sekor CS/E 3.5/50 Macro is a "reversed Xenotar" type lens, something I hadn't noticed up to now:

http://www.artaphot.ch/mamiya/e-ef-lenses/164-mamiya-sekor-e-ef-lenses/578-mamiya-sekor-e-50mm-f35-macro

Your Mamiya 3.5/50mm, if it is a Tessar type, should have four reflexes in front as well, but only three on the back side.

S


Thanks! Yeah - I‘ve gotten pretty confident telling simpler designs by looking at the reflections and this is almost certainly a Tessar. I always mention if there‘s some uncertainty left, because I rarely disassemble unusual lenses like that.

A reverse Xenotar is interesting… have found a couple of Reverse-Heliars among enlarging lenses and a number of Reverse-Tessars among high-magnification macro lenses, but Isn‘t a Reverse-Xenotar almost identical with a Planar? Could be interesting to test the Sekor E Macro at greater magnifications… could be very good at that. Do you know if it was used/advertised with additional extension rings or a bellows or isn‘t there anything out there because it‘s uncommon?


PostPosted: Wed Oct 11, 2023 3:52 pm    Post subject: Re: Mamiya Sekor 50 mm f/3.5 enlarging lens Reply with quote
simple.joy wrote:
stevemark wrote:


You can check that by carefully counting the reflexes before and after the aperture (e. g. using a small LED light in an otherwise dark room). The Sekor CS and E 3.5/50mm Macro lens should have four reflexes in front, and five reflexes at the back side. Interestingly, the Mamiya Sekor CS/E 3.5/50 Macro is a "reversed Xenotar" type lens, something I hadn't noticed up to now:

http://www.artaphot.ch/mamiya/e-ef-lenses/164-mamiya-sekor-e-ef-lenses/578-mamiya-sekor-e-50mm-f35-macro

Your Mamiya 3.5/50mm, if it is a Tessar type, should have four reflexes in front as well, but only three on the back side.

S


Thanks! Yeah - I‘ve gotten pretty confident telling simpler designs by looking at the reflections and this is almost certainly a Tessar. I always mention if there‘s some uncertainty left, because I rarely disassemble unusual lenses like that.

A reverse Xenotar is interesting… have found a couple of Reverse-Heliars among enlarging lenses and a number of Reverse-Tessars among high-magnification macro lenses, but Isn‘t a Reverse-Xenotar almost identical with a Planar? Could be interesting to test the Sekor E Macro at greater magnifications… could be very good at that. Do you know if it was used/advertised with additional extension rings or a bellows or isn‘t there anything out there because it‘s uncommon?


The older Mamiya Sekor TL/DTL/SX 60mm 2.8 Macro has the normal Xenotar 4/5 construction (and so the identical Yashica 60mm 2.8 ). The CS/E 50 3.5 the reversed build. Both basically a one element reduction on the double gauss (aka Planar) but it was not that simple in practice. The reason to go that route is quite well explained here: https://zeissikonveb.de/start/objektive/normalobjektive/biometar.html There the Rolleiflex Xenotar and Rolleiflex Planar lens diagrams also show that the Rolleiflex Planar is not a Xenotar/Biometar type. There is the opinion that the Biometar/Xenotar got as a rear group half the Topogon design. However the last Rolleiflex Planars and Xenotars became 6/4 double gauss designs again, AFAIK.

There are way more Xenotar/Biometar type lenses than we tend to think. The early post WWII Japanese 35mm rangefinder cameras, fixed or exchangeable lenses, quite often had that configuration. Some UK rangefinders of that period. A lot of SLR macro lenses. Enlarger lenses.

I thought for some time that the hybrid Planar/Plasmat macro/enlarger lenses were a separate development, now I think more that the hybrid Planar/Plasmat variety was another step on the Xenotar macro design philosophy. There was the older Meyer Kleinbild-Plasmat that had that hybrid design as well but I do not see much of a link to the later macro lenses.


PostPosted: Wed Oct 11, 2023 5:09 pm    Post subject: Re: Mamiya Sekor 50 mm f/3.5 enlarging lens Reply with quote
Ernst Dinkla wrote:


The older Mamiya Sekor TL/DTL/SX 60mm 2.8 Macro has the normal Xenotar 4/5 construction (and so the identical Yashica 60mm 2.8 ). The CS/E 50 3.5 the reversed build. Both basically a one element reduction on the double gauss (aka Planar) but it was not that simple in practice. The reason to go that route is quite well explained here: https://zeissikonveb.de/start/objektive/normalobjektive/biometar.html There the Rolleiflex Xenotar and Rolleiflex Planar lens diagrams also show that the Rolleiflex Planar is not a Xenotar/Biometar type. There is the opinion that the Biometar/Xenotar got as a rear group half the Topogon design. However the last Rolleiflex Planars and Xenotars became 6/4 double gauss designs again, AFAIK.

There are way more Xenotar/Biometar type lenses than we tend to think. The early post WWII Japanese 35mm rangefinder cameras, fixed or exchangeable lenses, quite often had that configuration. Some UK rangefinders of that period. A lot of SLR macro lenses. Enlarger lenses.

I thought for some time that the hybrid Planar/Plasmat macro/enlarger lenses were a separate development, now I think more that the hybrid Planar/Plasmat variety was another step on the Xenotar macro design philosophy. There was the older Meyer Kleinbild-Plasmat that had that hybrid design as well but I do not see much of a link to the later macro lenses.


Thanks for the input - that's very interesting and a wonderful coincidence because I was just thinking about that lens you've mentioned (the Macro-Yashinon 60 mm f/2.Cool. I'm not familiar with what the significant differences between 5-element Planar and 5-element Xenotar designs are. Could you tell me how you would identify the following lenses as Planar and Xenotar?



The green one is a Zeiss Planar design, the blue one a Xenotar, according to what you mentioned. (Both were drawn by me, so they might not be 100% accurate, but there are no high-res drawings on some lenses unfortunately).

I'd really appreciate it, if you would help getting me up to speed before I label something the wrong way again in the article I'm working on! 😅


PostPosted: Wed Oct 11, 2023 5:47 pm    Post subject: Reply with quote
Zeiss Oberkochen and Rollei later used the Planar name for a wide variety of double Gauss designs. Including what Zeiss Jena considered Biometar 5/4 designs. Like your lens diagrams show.

I mentioned the first Rolleiflex Xenotar and Planar lenses and in that case the Planar has a cemented front group instead of the Xenotar where the second and third element are cemented to a group. You will find the lens diagrams in the link I gave.


PostPosted: Wed Oct 11, 2023 7:31 pm    Post subject: Reply with quote
Typical Planar - six lenses in four groups:
http://www.artaphot.ch/mamiya/e-ef-lenses/164-mamiya-sekor-e-ef-lenses/577-mamiya-sekor-e-50mm-f2


Typical Xenotar:
http://www.artaphot.ch/topcon-re/re-auto-topcor-lenses/488-re-auto-topcor-58mm-f35-macro


"Inversed" Xenotar:
http://www.artaphot.ch/mamiya/e-ef-lenses/164-mamiya-sekor-e-ef-lenses/578-mamiya-sekor-e-50mm-f35-macro


Gr S


PostPosted: Wed Oct 11, 2023 8:35 pm    Post subject: Reply with quote
Ernst Dinkla wrote:
Zeiss Oberkochen and Rollei later used the Planar name for a wide variety of double Gauss designs. Including what Zeiss Jena considered Biometar 5/4 designs. Like your lens diagrams show.

I mentioned the first Rolleiflex Xenotar and Planar lenses and in that case the Planar has a cemented front group instead of the Xenotar where the second and third element are cemented to a group. You will find the lens diagrams in the link I gave.


stevemark wrote:
Typical Planar - six lenses in four groups:

Typical Xenotar:

"Inversed" Xenotar:

Gr S


Thank you very much! So, if I understand that correctly, there actually isn't really a unique 5-element Planar design, apart perhaps from the Oberkochen 80/2.8 Planar mentioned on zeissikonveb.de?
https://zeissikonveb.de/start/objektive/normalobjektive/biometar.html#:~:text=already%20had%20been-,substituted,-

That means most of the 5/4 lenses Oberkochen called Planar were actually Xenotars/Biometars...

As Ernst Dinkla has mentioned 5/4 enlarging lenses are indeed a thing, even though they are not very common... of more than 1700 entries for enlarging lenses on deltalenses around 26 are claimed to feature that design. That's less though than the 5/3 Heliar design with 73 entries.

https://deltalenses.com/product-category/enlarger-lenses/?swoof=1&pa_elements=5-4&really_curr_tax=18-product_cat


PostPosted: Wed Oct 11, 2023 8:42 pm    Post subject: Reply with quote
A couple more shots trying to use that wonderful square aperture shape:

Transforming taste info pixels by simple.joy, on Flickr

Mush-room with a view by simple.joy, on Flickr

As I've experienced with similar lenses (like the Wilon) it's significantly harder than celebrating fully square bokeh. Still fun though and less distracting.


PostPosted: Wed Oct 11, 2023 10:46 pm    Post subject: Reply with quote
simple.joy wrote:
stevemark wrote:
Typical Planar - six lenses in four groups:

Typical Xenotar:

"Inversed" Xenotar:

Gr S


Thank you very much! So, if I understand that correctly, there actually isn't really a unique 5-element Planar design, apart perhaps from the Oberkochen 80/2.8 Planar mentioned on zeissikonveb.de?
https://zeissikonveb.de/start/objektive/normalobjektive/biometar.html#:~:text=already%20had%20been-,substituted,-

The Oberkochen "Planar" 2.8/80 shown at the zeissikonveb.de site actually is even further away from the real (original) planar than the Xenotar. If you look at the patents of Xenotar type lenses you'll see that it's not really a "simplified Planar" as one might suspect from the lens sections. The glass selection on the rear part is different from a typical Planar. Haruo Sato, a well known Nikon lens designer, calls the Xenotar a "Planar-Topogon-hybride": Planar type in front, Topogon type in the rear part.

Original Schneider Xenotar: US2968221
Zeiss Jena Biometar (Xenotar type as well): US2683398

simple.joy wrote:
That means most of the 5/4 lenses Oberkochen called Planar were actually Xenotars/Biometars...

Yes.


PostPosted: Thu Oct 12, 2023 8:19 am    Post subject: Reply with quote
Interesting little lens. By how much did you stop it down to get this "rounded square" aperture shape?


PostPosted: Thu Oct 12, 2023 9:27 am    Post subject: Reply with quote
stevemark wrote:


The Oberkochen "Planar" 2.8/80 shown at the zeissikonveb.de site actually is even further away from the real (original) planar than the Xenotar. If you look at the patents of Xenotar type lenses you'll see that it's not really a "simplified Planar" as one might suspect from the lens sections. The glass selection on the rear part is different from a typical Planar. Haruo Sato, a well known Nikon lens designer, calls the Xenotar a "Planar-Topogon-hybride": Planar type in front, Topogon type in the rear part.

Original Schneider Xenotar: US2968221
Zeiss Jena Biometar (Xenotar type as well): US2683398


You're right - that looks quite different! Thanks for the patents. Interesting that Schneider had that so much earlier.

Dejan wrote:
Interesting little lens. By how much did you stop it down to get this "rounded square" aperture shape?


If using click stops it has to be stopped down to f/5.6 but it's possible to keep it inbetween at around f/4, which is what I probably did in most cases. There are other lenses with that aperture shape, but most of those are even slower - like the Will Wetzlar Wilon for example.


PostPosted: Thu Oct 12, 2023 10:40 am    Post subject: Reply with quote
simple.joy wrote:


As Ernst Dinkla has mentioned 5/4 enlarging lenses are indeed a thing, even though they are not very common... of more than 1700 entries for enlarging lenses on deltalenses around 26 are claimed to feature that design. That's less though than the 5/3 Heliar design with 73 entries.

https://deltalenses.com/product-category/enlarger-lenses/?swoof=1&pa_elements=5-4&really_curr_tax=18-product_cat


Interesting site. Did not know that the first Colorplan 90 2.5 has a 5/4 optical scheme too, no lens diagram but most likely double gauss related.

Yes, not that many Xenotars among the enlarger lenses compared to Heliars and Tessars, I did not check the number of Plasmats 6/4 among them, probably not that high in quantity either. There is also a risk that a 5/4 element/groups number does not represent a Xenotar/Biometar design. Not in enlarger lenses but there are several Tessar based lenses that have a optical scheme like the Schneider Korelle Xenar 75mm 2.8 , a type also called Super Xenar; https://casualphotophile.com/2020/05/13/schneider-kreuznach-super-xenar-50mm-f-2-8-lens-review/ so 5/4 but totally different.

Zeiss Oberkochen called more lens types "Planar", they simply sold better with that name. From Biometar, 'Planar' and Ultron versions up to complicated modern lenses where it is difficult to link them to the basic 'Planar' design. BTW there seems to have been a prototype Planar of around 1940 that already had some similarity to the Biometar. A fast Documar 35mm 2.8 is also from that period. The wide angle Ultragon, though linked more to the Topogon, could be seen as a first reversed Xenotar: https://en.wikipedia.org/wiki/Topogon.

Anyway the thread should be about your Mamiya Enlarger lens. Sorry that I derailed it.


PostPosted: Thu Oct 12, 2023 10:47 am    Post subject: Reply with quote
simple.joy wrote:
A couple more shots trying to use that wonderful square aperture shape:

Transforming taste info pixels by simple.joy, on Flickr

Mush-room with a view by simple.joy, on Flickr

As I've experienced with similar lenses (like the Wilon) it's significantly harder than celebrating fully square bokeh. Still fun though and less distracting.


Just curious what you used as a background?


PostPosted: Thu Oct 12, 2023 11:26 am    Post subject: Reply with quote
caspert79 wrote:


Just curious what you used as a background?


That's some colored aluminium foil.

Ernst Dinkla wrote:


Interesting site. Did not know that the first Colorplan 90 2.5 has a 5/4 optical scheme too, no lens diagram but most likely double gauss related.

Yes, not that many Xenotars among the enlarger lenses compared to Heliars and Tessars, I did not check the number of Plasmats 6/4 among them, probably not that high in quantity either. There is also a risk that a 5/4 element/groups number does not represent a Xenotar/Biometar design. Not in enlarger lenses but there are several Tessar based lenses that have a optical scheme like the Schneider Korelle Xenar 75mm 2.8 , a type also called Super Xenar; https://casualphotophile.com/2020/05/13/schneider-kreuznach-super-xenar-50mm-f-2-8-lens-review/ so 5/4 but totally different.

Zeiss Oberkochen called more lens types "Planar", they simply sold better with that name. From Biometar, 'Planar' and Ultron versions up to complicated modern lenses where it is difficult to link them to the basic 'Planar' design. BTW there seems to have been a prototype Planar of around 1940 that already had some similarity to the Biometar. A fast Documar 35mm 2.8 is also from that period. The wide angle Ultragon, though linked more to the Topogon, could be seen as a first reversed Xenotar: https://en.wikipedia.org/wiki/Topogon.

Anyway the thread should be about your Mamiya Enlarger lens. Sorry that I derailed it.


No, worries - I'm more than happy to talk about some other lenses and lens designs as well for a little bit. I'm always happy to learn some new things, because I certainly got lots of holes in my knowledge when it comes to lens design etc.

Here is a lens diagram of the Colorplan 90/2.5, where it is compared to an Elmarit: https://allphotolenses.com/lenses/item/c_4127.html

BTW. Deltalenses is the project of Mark (user "16:9" here on mflenses) and I'm helping him out as well as writing a couple of articles. We're going to need a lot more help though in filling the database to a reasonable extent and providing more accurate and complete information on many lenses, so if you (or anyone else here) is willing to help out, we would really appreciate it. Single lens reviews can be added via the comments on the page of each lens already, and if someone has an interesting idea for a unique in depth article (I've recently published one on Noritsu lenses here: https://deltalenses.com/the-makers-noritsu/) I feel like Mark is always up for suggestions.

Unfortunately it's not possible yet to check all plasmat designs separetly, but just from my personal experience there is a significant amount of those, from Schneider, Agfa, Staeble, Komura, Nikon, Konica, Tomioka, Computar etc. I would estimate that significantly more than 100 lenses feature that design, even though they will likely still be outnumbered by Triplets, Tessars and 6/4 Double Gauss designs.

The Dokumar lenses have very interesting lens designs (and quite varied as far as I know). I have the Dokumar 35 mm f/2.8 and used it recently:

Bookmark on the way to heaven by simple.joy, on Flickr

Aurora bottlearis by simple.joy, on Flickr

Not as good as the Dokumar 38 mm f/5.6 (which the Zeiss archive calls a "Lamegon" design) but still quite fun.


PostPosted: Mon Oct 23, 2023 1:23 pm    Post subject: Reply with quote
Nice find!

Delta Fun Fact: the Mamiya Sekor 35/3.5 is the fifth enlarger lens so far catalogued with a curved four-blade aperture - joining the Berophot 50/3.5 and 75/4.5, the second generation of Wilhelm Will Wilon's to which they are identical, and the oddball [V4] Schneider Comparon 75/4.5. If you know of any others, please let us know.

The similarly-diaphragm'd 50/3.5 Berophot was rumoured to have been made by Rodenstock. Notwithstanding Mamiya's pedigree, it wouldn't be the first time an established maker decided it was simpler to relicence a Meopta/Rodenstock/etc lens rather than gear up to make their own product line of a single item. Are we sure it's a Mamiya product through and through?

https://deltalenses.com/product/berophot-50-3-5/

Last edited by 16:9 on Mon Oct 23, 2023 10:24 pm; edited 2 times in total


PostPosted: Mon Oct 23, 2023 3:38 pm    Post subject: Reply with quote
16:9 wrote:
Nice find!

Delta Fun Fact: the Mamiya Sekor 35/3.5 is the third enlarger lens so far catalogued with a curved four-blade aperture - joining the Berophot 50/3.5 and the oddball [V4] Schneider Comparon 75/4.5. If you know of any others, please let us know.

The similarly-diaphragm'd Tessar 50/3.5 Berophot was rumoured to have been made by Rodenstock. Notwithstanding Mamiya's pedigree, it wouldn't be the first time an established maker decided it was simpler to relicence a Meopta/Rodenstock/etc lens rather than gear up to make their own product line of a single item. Are we sure it's a Mamiya product through and through?


Thanks for adding the lens! I changed the listing because it's actually a 50/3.5 lens: https://deltalenses.com/product/mamiya-sekor-50-3-5/

It certainly wasn't made by Rodenstock/Meopta, because it states "Lens Japan" on the outside. Of course there are also a lot of 50/3.5 ELs made by other companies in Japan, so I've got no idea if it is indeed a true Mamiya lens. If I'm not mistaken a vast majority of the Sekor labeled lenses (I've read "Sekor" stands for Setagaya Kōki, which was the company Mamiya acquired and then continued as their main lens production plant) was actually made by Mamiya in the Setagaya plant though. Because I've got no idea when this lens was made (there's no serial number on it), I'm not sure how telling that name still was...

It certainly feels like a very well made lens. Reminds me of the Konica Hexanon-EL 90 mm which seems similarly rare and well produced. So if I had to bet, I'd say this is indeed a Mamiya in-house production. I wonder what it was intended for though... have they ever produced a 35 mm enlarger? I've only been aware of the Mamiya Enlaheads (for smaller formats).

EDIT: All that being said, there are some interesting similarities between the Mamiya Sekor and Berophot lens... makes me wonder if they were made for the same device or distributor. Do you know where the trademark Berophot belonged to?


PostPosted: Mon Oct 23, 2023 7:09 pm    Post subject: Reply with quote
Thanks for picking up my typo.

Berophot belonged to the portfolio of Berlin-based reseller Beroflex AG. Their first-generation enlarger lenses (50mm and 75mm) were Japanese-made and variously branded Dixons / Prinz / Perfex / Vivitar et al. It has been speculated that the second-generation polycarbonate-bodied models were made by Rodenstock - but in fact they were made by Wilhelm Will. The 50/3.5 was also branded Macro-Doryt.

The Mamiya looks (at this distance) like a unique product, but such a one-off makes you want to double-check! Can you add some pix of the back and/or side of the lens, and fill in any other details like minimum aperture, weight and focal-flange distance on the Delta listing?

Thanks again - lovely playful pix as usual!


PostPosted: Sun Jan 07, 2024 10:00 pm    Post subject: Reply with quote
Got the little Mamiya enlarging lens out in the rain to catch some droplets (on the images, not the lens of course 😅):

Nature's scream by simple.joy, on Flickr

Twisted, but cable-minded... by simple.joy, on Flickr

Densely dropulated by simple.joy, on Flickr

Overall its rendering is really nice, even when stopped down, but at certain distances or with straight objects (like in the shot with the cable and the fence) it can produce an almost artificial/unnatural looking background, even when the (rounded square) bokeh highlights are not clearly visible. I'm sure there's some interesting opportunities in that... but I feel like it might work better in a city environment, not so much in my kind of (extremely) rural area.
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