![]() Many variations and improvements were made in subsequent decades. The illustration below, from Zeiss Archive shows exactly this Tessar version. It was produced in april/1911 (information based on its serial number 157538). The lens shown above, in brass barrel, is a vintage Tessar in its very first version with max aperture f/6.3 and impressive 70º coverage. In practical terms it could compete with other Anastigmats, far more expensive, and yet satisfy the most demanding photographers. That was important as lens coating was not yet available. Being simple and with few air/glass surfaces it gives less opportunities for flare. The virtue of this lens is that it has a relatively simple construction and delivers a very sharp image throughout the film plane even in the lower range of f stops. Maybe foreseeing the bright future for this new lens, from 1906 onwards, Carl Zeiss adopted a company logo designed after the Tessar rear doublet. The rear glasses are cemented and are the ones with convergence power to form image. Those are very weak in power and their role is related to helping in aberrations reduction. Tessar, named after the Greek word τέσσερα, téssera, that means four, for four glasses, has two air-spaced elements in front of the diaphragm. Unars were also symmetric, corrected and used air spaced doublets on both sides of diaphragm. Protars have symmetric cemented groups on both sides of diaphragm, 2, 3 and even 4 glasses each side, that is the case of Protar series VIIa, and were the first ones to correct astigmatism while offering apertures as large as f7 and more. In terms of filiation it was a rather fast rollout of ideas introduced with the remarkable Protar (formerly named Anastigmats, launched in 1890, by the same Carl Zeiss) and the Unar (also Zeiss design). Maybe you have a Tessar and just don’t know it. Until today, the same basic design can be found in lenses used in smart phones. Lenses using Tessar’s design reached the order of millions of units and equipped all kinds of cameras. ![]() The construction concept has found applications from large format down to Minox size. Introduced in 1902, it was created by Paul Rudolph, from Carl Zeiss. Tessar is probably the lens design most produced ever.
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