Originally Posted by AgX
The Xenar is even a further development from the triplet than the Tessar. The Xenar even got a further 5th lens and improved speed in those days.
You might be referring to the Xenator, not the Xenar? My understanding is that the Xenator is the 5-element lens (Gauss-type design?) and the Xenar is the 4-element lens (Tessar-type design).