Schmidt–Pechan prism

The Pechan design will invert or revert (flip) the image, depending on the orientation of the prism, but not both at the same time.

A paper, "Progress in Binocular Design", by Konrad Seil at Swarovski Optik shows that single-layer anti-reflective coatings on these surfaces maximized image contrast.

A well-designed dielectric coating can provide a reflectivity of more than 99% across the visible light spectrum.

A dielectric mirror coating is comparable in reflection effectivity, but makes the Schmidt–Pechan more expensive.

The Schmidt–Pechan furthermore shares the phase correction problems with other roof prisms.

[4] Despite complications from a purely technical point of view, Schmidt–Pechan prism type binoculars result in lighter, more compact and cheaper roof prism binoculars.

[5][6] In the early 2020s the commercial market share of Schmidt–Pechan prism type binoculars had become the dominant optical design compared to other prism type designs.