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Concave lenses list
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PostPosted: Sun Feb 20, 2011 2:13 pm    Post subject: Concave lenses list Reply with quote

I wish there would be one. I owned Zeiss Ultron and Schneider-Kreuznach Optivaron both having strong concave front element. Google returns CANON FD 2/35mm. Do you know of any other?


PostPosted: Sun Feb 20, 2011 3:31 pm    Post subject: Reply with quote

There is one: CV Ultron 35/1.7 Aspherical (L-mount)


PostPosted: Sun Feb 20, 2011 3:47 pm    Post subject: Reply with quote

Leica SUMMICRON-M 1:2/28mm ASPH
Leica Summilux-M 35mm f/1,4 ASPH
Leica Summicron-M 35mm f/2 ASPH
LEICA SUMMILUX-M 24mm f/1.4 ASPH (but maybe is the front element only flat)


PostPosted: Tue Feb 22, 2011 12:30 am    Post subject: Reply with quote

I have the canon 35 if anyone wants it---to many 35s now.

Sharp and only mildly radioactive.


PostPosted: Tue Feb 22, 2011 12:34 pm    Post subject: Reply with quote

Asahi Pentax Ultra-Achromatic Takumar 4.5/85mm
http://www.macrolenses.de/ml_detail_sl.php?ObjektiveNr=239
Zeiss UV-Sonnar 4.3/105mm http://www.macrolenses.de/ml_detail_sl.php?ObjektiveNr=301 and
Nikon UV-Nikkor 4.5/105mm http://www.macrolenses.de/ml_detail_sl.php?ObjektiveNr=298


(c) Marco Cavina

Have bi-concave front elements too.

If you consider the OPTIVARON (concave, but not biconcave)
http://www.schneiderkreuznach.com/archiv/pdf/variogon_super8.pdf
then you could add about all retrofocus lenses and fisheyes!!

So I guess what you really meant was a biconcave front element??


PostPosted: Tue Feb 22, 2011 4:31 pm    Post subject: Reply with quote

Thank you for additions to the list. Klaus: i was just interested in lenses having concave side of front glass turned outward.


PostPosted: Tue Feb 22, 2011 4:42 pm    Post subject: Reply with quote

OK, I thought so. These are called biconcave lenses.


PostPosted: Tue Feb 22, 2011 6:33 pm    Post subject: Reply with quote

Voigtlnder SC Skopar 28mm f/3.5 - and the same might go for more of the series


PostPosted: Tue Feb 22, 2011 9:30 pm    Post subject: Reply with quote

Zeiss Contax G Vario Sonnar 35-70/3.5-5.6, I noticed something odd about it and now I check the lens diagram.


PostPosted: Tue Feb 22, 2011 10:17 pm    Post subject: Reply with quote

The biconcave front element is a characteristic typical of UV-VIS-IR focusing lenses, or it is just a characteristic of a particular optical scheme ? I mean: do all the UV-VIS-IR lenses have a biconcave front element (to avoid focus shift between the three bands of light) ?


PostPosted: Tue Feb 22, 2011 10:22 pm    Post subject: Reply with quote

indianadinos wrote:
The biconcave front element is a characteristic typical of UV-VIS-IR focusing lenses, or it is just a characteristic of a particular optical scheme ? I mean: do all the UV-VIS-IR lenses have a biconcave front element (to avoid focus shift between the three bands of light) ?


No, not all, I think design engineers just copied, ehem borrowed the idea and used it to achieve their goals. The Sodern UV-VIS-NIR lenses for instance have a very different design. Russian lenses like the UFAR type also have different design.

That biconcave front element works (amongst other effects) also as a field flattener element, which could also be placed close to the end of the focus (Piazzy Smith invented that).

Dr W A Tronnier (who designed the ULTRON) won a bet since he claimed that he could make such a lens with biconcave front element, so the ULTRON was born out of a bet (which he of course won)!


PostPosted: Sat Mar 05, 2011 9:10 pm    Post subject: another: Reply with quote

leitz-schneider cinegon 10mm f 1,8 in M.mount covering super-8 (and giving a circular picture on an MFT)

p.


PostPosted: Sat Mar 05, 2011 9:47 pm    Post subject: Reply with quote

kds315* wrote:

No, not all, I think design engineers just copied, ehem borrowed the idea and used it to achieve their goals. The Sodern UV-VIS-NIR lenses for instance have a very different design. Russian lenses like the UFAR type also have different design.

That biconcave front element works (amongst other effects) also as a field flattener element, which could also be placed close to the end of the focus (Piazzy Smith invented that).

Dr W A Tronnier (who designed the ULTRON) won a bet since he claimed that he could make such a lens with biconcave front element, so the ULTRON was born out of a bet (which he of course won)!


Thanks, Master Wink ...


PostPosted: Sat Mar 05, 2011 10:00 pm    Post subject: Reply with quote

har har Very Happy Very Happy


PostPosted: Sun Mar 06, 2011 10:02 pm    Post subject: Reply with quote

Weak concave :

NIKKOR-S Auto 5cm f/2 lens
http://imaging.nikon.com/products/imaging/technology/nikkor/n02_e.htm


PostPosted: Mon Mar 07, 2011 6:32 am    Post subject: Reply with quote

M-hexanon 35/2

Is this a common theme for 35mm RF lens?


PostPosted: Mon Mar 07, 2011 10:29 am    Post subject: Reply with quote

aleksanderpolo wrote:
M-hexanon 35/2

Is this a common theme for 35mm RF lens?


Nice one, good to know. Sure theme is ok.


PostPosted: Wed Mar 09, 2011 9:11 pm    Post subject: Reply with quote

Some diagrams :

Konica M-Hexanon 35/2,0



Voigtlander Ultron 35/1,7 aspherical



Leica Summilux 35/1,4 ASPH

(M-Hexanon : http://www.dg77.net/photo/leicaM/hexanon35.htm#formula )


PostPosted: Sat Aug 29, 2020 7:31 pm    Post subject: Reply with quote

Bi-concave front element. Regardless of Autofocus, APS-C.

Fujifilm XF 50mm f1 WR lens.

#1


https://fujifilm-x.com/x-summit-london-2020/


Last edited by Blazer0ne on Sun Aug 30, 2020 1:58 am; edited 2 times in total


PostPosted: Sat Aug 29, 2020 11:42 pm    Post subject: Reply with quote

kds315* wrote:
OK, I thought so. These are called biconcave lenses.


Surely biconcave elements are concave on both sides. The concave side of a meniscus lens or plano concave lens could be outermost and still meet Pancolart's requirement. I don't know of any lens designs that do this, so they may in practice all be biconcave...


PostPosted: Sun Aug 30, 2020 12:27 am    Post subject: Reply with quote

The new D FA* Pentax 85mm 1.4 also has a concave front element
Pentaxforums.com


PostPosted: Mon Aug 31, 2020 9:19 am    Post subject: Reply with quote

Blazer0ne wrote:
Bi-concave front element. Regardless of Autofocus, APS-C.

Fujifilm XF 50mm f1 WR lens.

#1


https://fujifilm-x.com/x-summit-london-2020/


Is it just me that find that group of four possibly cemented lens elements intriguing? I don't know of any other lens that has it.


PostPosted: Wed Sep 02, 2020 5:20 am    Post subject: Reply with quote

Yes, very unusual to use a cemented quadruplet. Manufacturing cost increases enormously when cementing more than 2 lens elements due to the precision alignment required, while anti-reflection coating of separated elements is usually cheaper. But, it's the only way to fit a lot of glass into a small space and for such a special lens, cost is no object for its customers.


PostPosted: Mon Sep 07, 2020 3:37 pm    Post subject: Reply with quote

Another one is the Nikon Z 50mm f/1.8 S (though it looks like it's got a doublet up front).