Zeiss Ikon Super Ikonta C (530/2) Compur Rapid/Tessar f4.5, "demo"

[Ole]

Tessars were designed for f4.5 really; f3.5 was already stretching it a bit and I find that f2.8 makes it more or less useless at that aperture...

That depends a bit on the focal length. The 5cm/2,8 on my Welti is great, even wide open. So is the 7,5cm/3,5 on my Zeiss Ikon. And the various 135, 150, 180, 210 and 300mm f:4.5 lenses, and the 50cm/6,3 one. Shorter focal lengths can have larger max aperture without undue loss of definition.

[Jim Jones]

Tessars were designed for f4.5 really; f3.5 was already stretching it a bit and I find that f2.8 makes it more or less useless at that aperture...

This may be true in larger formats. However, two of the sharpest lenses for 35mm I ever checked were a Leitz Elmar 50mm f/2.8 and the GN-Nikkor 45mm f/2.8.

[Mike Kovacs]

There was a reason why the Zeiss slogan for the Tessar was "The Eagle Eye of the Camera".