giordano Posted March 8, 2012 Share #1 Posted March 8, 2012 Advertisement (gone after registration) A recent message in the Customer forum includes this passage: From what I have read Zeiss did not have a good 50mm f2 design and so did what many camera manufacturers did -they went to another manufacturer and arranged to make the other firm's lens under licence and put their own name on it. The 50 mm f2 Zeiss Sonnar of 1932 was the 2 inch f2 Speed Panchro from Taylor Taylor and Hobson, which in its native form was fitted to the Reid 35mm camera.Is there any truth in this? I thought the Speed Panchros were modified-double-Gauss designs while the original 50mm Sonnars were triplet-derived. Not to mention that the Speed Panchros were computed for film cameras: would a 2 inch lens have delivered Zeiss performance across the double-size 24x36? And the Reid camera didn't come along until quite a few years after the Contax. Link to post Share on other sites More sharing options...
Advertisement Posted March 8, 2012 Posted March 8, 2012 Hi giordano, Take a look here TTH / Zeiss. I'm sure you'll find what you were looking for!
luigi bertolotti Posted March 9, 2012 Share #2 Posted March 9, 2012 Afaik Sonnar was a design by L. Bertele patented in 1924... but the history of optical designs is a complex one, and there can be some grain of truth in the reported story... I would like to verify if Zeiss patent was valid in England too... matter for serious studies... Link to post Share on other sites More sharing options...
lars_bergquist Posted March 9, 2012 Share #3 Posted March 9, 2012 Cooke Optics - Wikipedia, the free encyclopedia This is a useful overview of TT&H history. For the rest, Luigi, you are right about the Sonnar designs. These were massively cemented triplets (three-group lenses, to cut down on reflective air-glass surfaces) with six and seven elements respectively. The simple formulas were: F:2 5cm Sonnar: 1 - 3 - / - 2 F:1.5 5cm Sonnar: 1- 3 - / - 3 Copies and derivatives were close to impossible before 1945, when all German patents were declared void as the Reich that had issued them no longer existed. Coating meant that the Sonnar designs were no longer superior to double-Gauss designs which also offered designers more degrees of freedom to correct aberrations. From the late 1950's, Sonnar designs faded out of the picture except for the 135mm and 180mm designs which continued to be used by Nikon e.g. The Planar was a Zeiss design by Rudolph from the 1890's. This was as far as I know the first double-Gauss camera lens, but quite flarey due to its eight air-glass surfaces, so Zeiss did not exploit it much before the 1950's, when coating made it practical. TT&H however pioneered its modified form where the last element is split up into two thin free-standing biconvex elements. They licensed the design to Schneider who named it Xenon. Its last avatar was the 1:1 Noctilux. I have not found any design facts about the original Super Panchro lenses, but like the Opic, these were cine lenses. The name is still used by Cooke Optics which is a company resulting from a buyout of the photo lens part of TT&H in 1998. TT&H is still in business in Leicester, making measurement equipment! LB Link to post Share on other sites More sharing options...
luigi bertolotti Posted March 9, 2012 Share #4 Posted March 9, 2012 Cooke Optics - Wikipedia, the free encyclopedia This is a useful overview of TT&H history. For the rest, Luigi, you are right about the Sonnar designs. These were massively cemented triplets (three-group lenses, to cut down on reflective air-glass surfaces) with six and seven elements respectively. The simple formulas were: F:2 5cm Sonnar: 1 - 3 - / - 2 F:1.5 5cm Sonnar: 1- 3 - / - 3 Copies and derivatives were close to impossible before 1945, when all German patents were declared void as the Reich that had issued them no longer existed. Coating meant that the Sonnar designs were no longer superior to double-Gauss designs which also offered designers more degrees of freedom to correct aberrations. From the late 1950's, Sonnar designs faded out of the picture except for the 135mm and 180mm designs which continued to be used by Nikon e.g. The Planar was a Zeiss design by Rudolph from the 1890's. This was as far as I know the first double-Gauss camera lens, but quite flarey due to its eight air-glass surfaces, so Zeiss did not exploit it much before the 1950's, when coating made it practical. TT&H however pioneered its modified form where the last element is split up into two thin free-standing biconvex elements. They licensed the design to Schneider who named it Xenon. Its last avatar was the 1:1 Noctilux.(*) I have not found any design facts about the original Super Panchro lenses, but like the Opic, these were cine lenses. The name is still used by Cooke Optics which is a company resulting from a buyout of the photo lens part of TT&H in 1998. TT&H is still in business in Leicester, making measurement equipment! LB (*) in fact, I'm very proud to have a Summarit 1,5 (=Xenon - postwar - coated) which has the TTH engraving and patent # on the barrel but, coming back to the orignal post quoted by Giordano, those considerations make imho very unprobable that Zeiss "licensed" the Sonnar design from TTH... the timing of the "Xenon biz" is not so far from the hipotetical "Sonnar biz"... why should TTH have imposed to Leitz the engraving of their name/patent on the lenses exported to UK/USA and not made the same for Zeiss ? I haven't ever seen a Sonnar with such engravings... Link to post Share on other sites More sharing options...
lars_bergquist Posted March 9, 2012 Share #5 Posted March 9, 2012 It is perfectly clear that Ludwig Bertele designed the 50mm f:2 Sonnar in 1924, and that the 1.5 lens was a straightforward derivative of it. Both lenses were launched with the Contax I in 1932. The design has nothing whatever to do with any double-Gauss one, as pioneered by P. Rudolph in 1896 (Planar) or any later derivatives by TT&H. Sonnar designs seem to have their ultimate roots in simpler triplet designs, such as the original 'Cooke Triplet'. LB Link to post Share on other sites More sharing options...
colorado Posted March 12, 2012 Share #6 Posted March 12, 2012 The reference for my comment about the TTH Speed Panchro and the Contax camera comes from an article in the Amateur Photographer magazine for the week ending August 18 1990.page 63 written by Stewart Bell who was then the magazine's lens expert. Bell's article was an insert into a review of a Leica 2f. Link to post Share on other sites More sharing options...
stevemark Posted April 20, 2012 Share #7 Posted April 20, 2012 Advertisement (gone after registration) A recent message in the Customer forum includes this passage: Is there any truth in this? I thought the Speed Panchros were modified-double-Gauss designs while the original 50mm Sonnars were triplet-derived. Not to mention that the Speed Panchros were computed for film cameras: would a 2 inch lens have delivered Zeiss performance across the double-size 24x36? And the Reid camera didn't come along until quite a few years after the Contax. No, this is a mistake. Basically there were three successful anastigmatic lens design lines starting from the 1890ties, when Schotts "new" barium glasses became available: 1) Cooke Triplet (simple triplet) 2) Zeiss Protar & Tessar (asymmetric pair of doublets, ie four lenses) 4) Zeiss Planar (symmetric, 6 lenses in 4 groups) The Sonnars (starting from 1931) are based on the triplet approach (2/5cm, 1.5/5cm, 2/8.5cm, 4/13.5cm, and 2.8/18cm being the classic ones); all of them had only three elements which gave a superior contrast before coatings were invented by Zeiss/Smakula in 1936. The Xenon 1.5/5cm is based on the TT&H cinema lenses ("Lee opic lens" and "Speed panchro"); they were asymmetrical planar type lenses designed by the excellent British lens designer Horace Lee. The Summar 2/5cm is a planar type as well. Some additional information including the mentioned lens cross sections can be found on my website: Zeiss Tessar Zeiss Sonnar Zeiss Planar und Biotar Really interesting is also the stepwise development of the Sonnar f1.5 lenses from the original triplet via the Ernostars: Zeiss Sonnar 5cm 1:1.5 Stephan Link to post Share on other sites More sharing options...
lars_bergquist Posted April 21, 2012 Share #8 Posted April 21, 2012 Lieber Herr Koelliker! In spite of the fact that Rudolph was the author of both the Protar and the Tessar, I cannot but regard the Tessar as a straightforward derivation of the Cooke triplet – one with the rearmost element replaced by a cemented two-element group. Developing it from the Protar takes quite a bit of both mental and optical contortion – switching the positions of the first two elements, indeed! A look at the diagrams in your article makes that abundantly clear. I have worked with a 50mm Tessar on a Kine-Exakta. As I write there hangs in front of me two large exhibition-grade b&w prints both made with the same coated 75mm f:3,5 Tessar on a 6x6cm roll film Zeiss Super-Ikonta. Their sharpness leaves nothing to be desired; but both were made at f:8. I would not have dreamt of using that lens wide open however. I have never tried the 2.8 Tessar in any focal length but 40mm (with a Rollei 35), but from what I have seen, the old fast Tessars were even softer at full aperture. The only Elmars I have actually worked with (and occasionally still use) is the 1950's 2.8 version, and the 60mm Visoflex lens, which are of course not representative. The old man from the age B.C. (Before Coating) Link to post Share on other sites More sharing options...
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