Was the Tessar re-designed around 1930-31

[Ian Grant]

I ask this question for good reasons. The Compur shutter's changed from Dial-set to Rim-set and became standardised, that standard is still with us today with the standard shutter sizes.

But how did the Tessar lens design change, did they change the glass used in the elements. I've noticed that older Rim-set Tessars seem to have better contrast, and are less prone to flare. I should add that's based on visual observations and practical use not scientific measurements, and only based on the 5 or 6 LF Tessar's I own.

Ian

 

[Anscojohn]

According to several sources I checked, the modified triplet, four element three group Tessar formula has remained the same since first calculated by Rudolph, ca. 1901.

 

[Ole]

The Tessar was redesigned repeatedly, all the way from the original patent to around 1980.

Whether any of these "tweaks" affected contrast and flare, I do not know.

 

[Ian Grant]

The Tessar was redesigned repeatedly, all the way from the original patent to around 1980.

Whether any of these "tweaks" affected contrast and flare, I do not know.

I agree with that, but it appears there may have been a big re-compute / re-design in the early 30's. Optical glass had changed significantly allowing much faster lenses like the f2 Summar etc.

Ian

 

[Mark Layne]

One major recomputation for 35mm was between the Contaflex Super and the Super D
Mark

 

[df cardwell]

Part of the Zeiss combine was the glassmaker Schott, who worked hand-in-hand with the lens makers. New glass was developed to satisfy new designs, new designs promoted new glass types.

Zeiss design was evolutionary. Since the marketing department never ran the company, the lenses were usually the best they could be in any era, and small improvements were normal. They might not show up in patent literature, for the Tessar patent was, as Kingslake described it, " extremely general ".

My newest Tessars, souvenirs from a winter in Prague in the '90s, are almost unbearably contrasty.