# Planar

> A symmetric Double-Gauss: two cemented halves around a stop — the Planar layout.

![Planar](https://www.loomrume.com/optics/stills/planar.png)

**Paul Rudolph** · 1896, Jena — Zeiss Planar

Rudolph’s Planar is a Double-Gauss: two almost symmetric halves around a stop, each a crown–flint pair. The symmetry cancels a lot of off-axis colour and distortion. Zeiss sold it as a fast anastigmat; later every camera company grew a version.

The name is the flat field, not a plane of glass. On the bench the stop sits in the middle and the meter sits where the plate would.

## Sources

- [Double-Gauss lens](https://en.wikipedia.org/wiki/Double-Gauss_lens)
- [Paul Rudolph](https://en.wikipedia.org/wiki/Paul_Rudolph_(physicist))

## Links

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