Just happened to read a couple of articles discussing the use of lanthanum oxide in old Leica lenses (here and here, if anyone else is interested). As I understand it, these were, in effect, the ED glass of the day, enabling chromatic aberration to be reduced.
It begs the question: did any of these types of glass ever made it into Leitz binoculars? On the one hand, binoculars are low-magnification devices compared to, say, astro/spotting scopes; and the external focus systems of porro prism binoculars such as Leitz made in the 1950s, it has been said, results in chromatic aberration being less of an issue than in internally focusing roof binoculars - both of which would limit, or even eliminate, the need for ED glass (or the 1960s-era equivalents). But then at least some of the Leica lenses it went into, like the 50mm f/2.8s, were effectively low magnification devices, too; and internal focusing was one of the key innovations in the Trinovid range...
Incidentally, reading about Leica lenses makes one (well at least it made me!) wonder to what extent the optical talent at Leitz went into camera lenses rather than binoculars! I suppose there was not the same demand for quality at any price in binoculars as there is amongst photography buffs, but when one realizes that aspherical elements were being used in things like the Noctilux back in the sixties, one wonders what might have been done (and at what price!!!) had Leitz unleashed the full force of their optical talent into binoculars. What was achieved in terms of field of view by the very first generation Trinovids, for instance, is still impressive today - although I suppose with modern eyepiece designs there is less need for the complex prism-mirror combo. I'd dearly love to try a Retrovid version of those!!!
It begs the question: did any of these types of glass ever made it into Leitz binoculars? On the one hand, binoculars are low-magnification devices compared to, say, astro/spotting scopes; and the external focus systems of porro prism binoculars such as Leitz made in the 1950s, it has been said, results in chromatic aberration being less of an issue than in internally focusing roof binoculars - both of which would limit, or even eliminate, the need for ED glass (or the 1960s-era equivalents). But then at least some of the Leica lenses it went into, like the 50mm f/2.8s, were effectively low magnification devices, too; and internal focusing was one of the key innovations in the Trinovid range...
Incidentally, reading about Leica lenses makes one (well at least it made me!) wonder to what extent the optical talent at Leitz went into camera lenses rather than binoculars! I suppose there was not the same demand for quality at any price in binoculars as there is amongst photography buffs, but when one realizes that aspherical elements were being used in things like the Noctilux back in the sixties, one wonders what might have been done (and at what price!!!) had Leitz unleashed the full force of their optical talent into binoculars. What was achieved in terms of field of view by the very first generation Trinovids, for instance, is still impressive today - although I suppose with modern eyepiece designs there is less need for the complex prism-mirror combo. I'd dearly love to try a Retrovid version of those!!!