Elmar Vs. Tessar or why did the Tessar conquer the world?

[tunalegs]

So this is something I've pondered, the Elmar and Tessar formulas are very similar, both very good, but the Tessar type lens has been produced by all sorts of companies in all sorts of focal lengths, for use with all sorts of formats. Even the soviet Elmar clones were only copies on the outside, the glass inside was of the good old Tessar formula.

Does anybody know why this is? Is it as simple as the Elmar being newer was still protected by patents in the early days of 35mm cameras? If so how come clones did not appear after the war in any appreciable numbers? Was it perhaps more difficult to compute a good Elmar type than it was to compute a Tessar type? Was the contemporary Tessar just a better performer and thus more worthy of copy?

I have thought about these things but been unable to find any hints. Any solid facts or zany conspiracies will be greatly appreciated.

 

[Sejanus.Aelianus]

The wikipedia page is helpful in this context: http://en.wikipedia.org/wiki/Tessar

 

[Dralowid]

It is worth remembering that pre war Zeiss was an optical empire happy to sell products and licenses to a huge number of manufacturers. A keen acquirer of other companies too. You can find their lenses on a wide array of cameras produced by others as well as their own.

Although also primarily an optical manufacturer, Leitz was smaller and apparently more focussed on its own product. It has been said that their diversification into the photographic market was driven by declining sales of their scientific equipment rather than thinking that photography was a natural fit. The list of manufacturers Leitz sold lenses to is not large, Welta and Nagel are two that come to mind. They didn't even bother to make their own alternative to the all conquering 1.5 Sonnar, filling the gap instead by producing a design under license from others.

The two companies and their strategies, when taken in the context of the whole product ranges, are very different and is demonstrated by the product.

Quite whether this answers the OP's question is unclear but does at least explain why Zeiss Tessars crop up in all sorts of places.

Michael (who fully expects to be shot down in flames)

 

[sevo]

As much as Leitz may claim that it is not so, the Elmar IS a Tessar clone, well within the range of variations Zeiss produced over the course of time, and closer to the mainstream than many other variations on the topic of Tessars.

By the time the patents on the Elmar had run out, so had the patents on many other second generation Tessars and Tessar clones. And, thanks to Zeiss losing their patents as a consequence of the war, even the latest f/2.8 Tessar and the Sonnar and Planar were out there to grab, and so were the Zeiss formulas for their computations and their latest glass types. That is, anybody who designed third generation Tessars built them on the latest Zeiss Tessar, improved by new glasses and better calculations, rather than faithfully cloning the already superseded Elmar design.