Ultravid Glass (1 Viewer)

This is a "dumb" question because I haven't read up on Leica optics systems. Anyway, what type of glass is used in the Ultravids? Is it an ED glass?

Hogjaws said:

This is a "dumb" question because I haven't read up on Leica optics systems. Anyway, what type of glass is used in the Ultravids? Is it an ED glass?

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My understanding is that it is not ED glass. The objectives will use two elements, a crown and a flint. Decent quality prisms are usually made from Bak4 glass according to various sources. The eyepieces will be made from a mix of glass, but not ED. I'm not sure if Leica ever use extra low dispersion elements in their camera lenses, but they use flouride glass in some scopes. (Though described as Flourite in some Leica literature.) In Leica-land the inclusion of such expensive glass is indicated by the APO designation. The new Canon 10x40 IS uses ED glass (referred to as UD glass in Canon-land).

Leif

Leif said:

... I'm not sure if Leica ever use extra low dispersion elements in their camera lenses, but they use flouride glass in some scopes. (Though described as Flourite in some Leica literature.) In Leica-land the inclusion of such expensive glass is indicated by the APO designation. ...

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Leica is a pioneer in photographic lens designs that employ exotic glass, with some of those glass types being formulated at their research facility (of the Leitz era). They are pleased to divulge lens particulars, although the info is sometimes buried.

For example, a recent benchmark goes by the name Summilux-M 50 ASPH. From the optical description, it would seem to deserve an APO label, too.

Quoting from the glossy:

Glass with anomalous partial dispersion (elements 2/3) was used to ensure correct color rendition and deliver strong imaging performance. Lens element 2 is made of a fluorite-type glass, while glass originating from the former Leitz glass laboratory was used for element 3. Lens element 4 has an aspherical surface. Alongside the aspherical element, glass with very high refractive power was also used to minimize monochrome imaging aberrations (elements 1/6/7).

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As an M shooter, this one is high on my Christmas list. The economizations that appear to restrict glass options for the Ultravid bins are not present with the photographic M and R product line. Of course, it shows in the price!

In the January issue of LeicaWorld (US), the manager of Leica Sport Optics mentioned that the Flourite elements are used in the Ultravids as well as aspheric elements in the compact models (see page 24). In most cases, Flourite has even better color fidelity than ED elements, though it is a bit more fragile. I had a friend who managed to completely shatter a 100mm flourite astronomical objective by knocking it on a doorway.

The objective itself is almost certainly the usual crown/flint combination--it would be one or more intermediate elements that are made of flourite crystal in the Leica Ultravids.