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What is this optical formula?
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PostPosted: Wed Sep 16, 2020 10:11 pm    Post subject: Reply with quote
So here's another one ... Wink



Gr S


PostPosted: Wed Sep 16, 2020 10:38 pm    Post subject: Reply with quote
Looks like a smartphone camera lens iirc...


PostPosted: Thu Sep 17, 2020 1:29 am    Post subject: Reply with quote
visualopsins wrote:
Looks like a smartphone camera lens iirc...

Yes. Something like this: https://www.imaging-resource.com/news/2013/07/17/check-out-the-lens-of-the-nokia-lumia-1020-smartphone-cut-in-half .


PostPosted: Thu Sep 17, 2020 2:22 am    Post subject: Reply with quote
stevemark wrote:
So here's another one ... Wink



Gr S


I have no idea what optical formula that is but I want to try it.


PostPosted: Thu Sep 17, 2020 4:12 am    Post subject: Reply with quote
Is it a design without a front group / rear group configuration, a "7e/7g Singlet"? Smile

Edit: now I wonder if each element of a Sonnar was a "7e/7g Singlet"...


PostPosted: Thu Sep 17, 2020 9:03 am    Post subject: Reply with quote
calvin83 wrote:
visualopsins wrote:
Looks like a smartphone camera lens iirc...

Yes. Something like this: https://www.imaging-resource.com/news/2013/07/17/check-out-the-lens-of-the-nokia-lumia-1020-smartphone-cut-in-half .


A route to designs like that was followed by Eastman Kodak in the Pocket Instamatics (Ektramax) > Kodak Disc Camera. Either glass or polymer aspheric elements in them. Sometimes a two element lens design with an aspheric surface can be cheaper in production than a normal Triplet: The Kodak KB10 point and shoot fixed focus 30mm 8.0. I still like to assemble two of them to an estimated 17mm symmetric lens.
After the Disc cameras similar optics for CD players etc were sold, laser optics in general, then more and more complex aspheric lenses for mobile phone cameras.


PostPosted: Thu Sep 17, 2020 10:12 am    Post subject: Reply with quote
visualopsins wrote:
stevemark wrote:
cbass wrote:

Although the pdf's are informative that still doesn't answer the question about which optical formula it is. The best guess so far is ernostar.


Sure it's an Ernostar - even though the first "Ernostar" wasn't an Ernostar: In fact the Gundlach Ultrastigmat was the first lens to have the structure we today call "Ernostar".

S


Gundlach Ultrastigmat was designed in 1916
Ernostar was designed in 1923

ref:

https://oldlens.com/ultrastigmat%2050mmf075.html\

and

https://oldlens.com/lenshistory.html


Correct. Most Ultrastigmats found their way in the movie industry, some Flickr images today show they were not bad at all. I rather call the lens diagram shown "Ultrastigmat like" and some developments "Enhanced Ultrastigmat". C.C. Minor also had a patent for another version with a two element rear part. He deserves some credit.

The Ultrastigmat design inspired more people than Bertele, Hugo Hahn of the Optische Werke Rüdersdorf A.G. aka Rüo-Optik, designed similar lenses shortly afterwards. Interesting thread here: https://www.dpreview.com/forums/thread/4467990
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