# Sonnar

> A front glass and two thick cemented groups — Bertele’s 1932 Sonnar, built for speed before coatings.

**Ludwig Bertele** · 1932, Jena — Zeiss Sonnar for Contax

Bertele had already made the Ernostar at Ernemann — a fast lens with too many air–glass faces, so it flared. At Zeiss he glued more of those faces together. The name is from Sonne, the sun: a 50 mm that opened to f/1.5 on the new Contax, when coatings did not yet exist and every extra surface stole light.

This board is the seven-glass recipe: a front singlet, a thick cemented triplet, then another behind the stop. Rudolph’s [Planar](https://www.loomrume.com/examples/planar.md) is the other Zeiss anastigmat of the era — more air, more surfaces, a flatter field. The Sonnar is the compact, contrasty one. In the USSR they called the copies Jupiter.

## Sources

- [Zeiss Sonnar](https://en.wikipedia.org/wiki/Zeiss_Sonnar)
- [Ludwig Bertele](https://en.wikipedia.org/wiki/Ludwig_Bertele)

## Links

- [HTML](https://www.loomrume.com/examples/sonnar)
- [Open in Studio](https://www.loomrume.com/experiments/new?template=sonnar)
- [llms.txt](https://www.loomrume.com/llms.txt)