Assertion: kellner eyepiece | /r/CapableOf | split up the three-element field lens
Facets:
value: with one extra air gap
type: OTHER
Source sentences:
text: The König eyepiece shown here (many other eyepiece designs are also due to Albert König) is based on the Orthoscopic design, but splits up the three-element field lens with one extra air gap, so that it consists of a single eye lens, a two-element lens in the middle, and a single field lens.