 Posted: Wed May 23, 2012 3:12 am Post subject: |
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iangreenhalgh1 wrote:
| Orio wrote: |
The statement that the Elmar is not a Tessar because it's a triplet derivation, is misleading: the Tessar, too, is a Cooke Triplet's derivation.
And the succession line Cooke's Triplet->Tessar->Elmar is pretty much consolidated in the photography history books. |
The Elmar and Tessar are very similar from what I've read, both being 4 elements in 3 groups with two air spaced elements in front of the aperture and a cemented doublet behind. The Tessar was developed from the Unar which was the same at the front but had an air spaced pair for the back half too. The Elmar was developed from a 5 element lens called the Elmax which had a cemented triplet behind the aperture. It's debatable to what extent they owe their design to the Cooke Triplet as the Tessar was developed by Rudolph from his earlier double Anastigmat design which had four air spaced elements, whether this work was partly based on the Cooke Triplet or not is debatable. I suppose to a degree, all of the later anastigmats and tessar/elmar types are developments of the Cooke Triplet even if their actual design lineages don't trace back to it as their designers were all familiar with the Triplet design and were seeking to improve upon it.
I have discovered that there is not that much difference between a good triplet and a tessar type, I have found the Rodenstock Trinar Anastigmat on my 1930s Franka Rolfix, the Novar-Anastigmat on my 1950s Zeiss Ikonta-M and the Voigtar on my 1930s Voigtlander Bessa are all very good lenses, they compare favourably in sharpness to the Skopars and Tessars I have tried of the same vintages. Same with the 50mm Trioplan and Meritar triplets I have, they compare favourably to the Tessars and Industars I have.
The differences boil down to performance in the corners at large apertures, the triplets are softer in the corners than the Tessar/Skopar/Elmar types when shot at the widest couple of stops, but when you get to the middle of their aperture ranges the differences become very hard to discern indeed.
What I'm getting at is the design of the lens and the number of elements isn't that important, a good triplet takes great pictures if used right, as does a good Tessar/Skopar/Elmar, it's far more valuable to invest time in technique than worrying about the piece of glass you're using, if it's good enough it's good enough, regardless of it's design.
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I don't care who designed it, who made it or what country it comes from - I just enjoy using it! |
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