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Lens Coating

Our coating expertise

The high-performance optics from Carl Zeiss are made from a variety of lenses. Each transition from air to glass with uncoated lenses, however, clouds your image. Preventing this is the core expertise of Carl Zeiss and gives the products from Wetzlar their status of being the brightest in the world. You benefit from this: At twilight or even during stand hunting at night.
T* is the most important coating when it comes to the brightness of observation optics or riflescopes. Invented 80 years ago and constantly developed further, it guarantees a unique brightness. A product advantage that you can experience directly.
The same goes for the dielectric mirror: Over 70 layers prevent light loss in the elaborate Carl Zeiss prism systems. More layers increase the razor-sharp details of the image or guarantee a clear view even in bad weather.
Carl Zeiss makes it clear what’s important in premium optics, and has even invented the technology it uses itself.

What does the T* stand for on ZEISS products?

Carl Zeiss T* is a guarantee of the brilliant, high-contrast images­­ which you will experience above all in adverse light conditions and in the twilight when you focus on your target through the binoculars and get it firmly in your sights through the riflescope.

 

The process was developed by Alexander Smakula some 80 years ago in the Carl Zeiss workshop in Jena, and the patent was registered in November 1935.


Alexander Smakula from Carl Zeiss Jena had at that time already discovered that when light enters or leaves a lens, a certain percentage of the light is reflected from the boundaries. Depending on the type of glass used this is usually between 4 and 8%, and depending on the number of lenses the total light lost can be more than 50%­. Smakula countered this significant disadvantage by covering the surface of the lenses with extremely thin layers of special materials. In doing so he changed the transfer of air to glass, thereby reducing the reflections. This led to greatly improved light transmission. Binoculars and riflescopes with this ­"Transmission layer­" were from that point, given the designation "T", and the improved multi-layer coating developed at the end of the ­‘70s was named "T*". The process involves the vapour deposition in a high vacuum of layers of material, with each of the six or so layers adding approx. 1/10,000 mm.

 

Today we call this process "coating" or "anti-reflection coating". It is in common use with anyone who wears glasses or uses hunting optics. For them, Smakula's findings have led to bright, high-contrast images without distracting reflections: a feature of all sophisticated ZEISS optics that we take for granted today­.

 

The coating is still known as the Carl Zeiss T* multi-layer coating. Behind it, however, there is no specific formula for building up the layers. Instead, it is a technology that is constantly adjusted to suit new glass materials and requirements, which varies from lens to lens.

For us, the Carl Zeiss T* multi-layer coating is a core skill, and one that we are constantly developing.

What is the LotuTec® coating?

Carl Zeiss has developed a coating for the lenses of binoculars and riflescopes that gives you clear and unrestricted visibility whatever the weather. You know how irritating it is when raindrops land on the lens in bad weather and impair your visibility.

We took as our example the leaves of the lotus plant with their water-resistant (hydrophobic) qualities and added a multi-layer protective coating (LotuTec® coating) on the external lenses of many ZEISS devices­. This ensures that water rolls off the glass straight away without leaving any residue and that dirt and fingerprints do not stick to the lens.


The Carl Zeiss LotuTec® coating has no effect on either the light transmission or the scratch resistance. On the contrary: you will find the extremely smooth surface of the lenses on your valuable binoculars even quicker and easier to clean.

What is a "dielectric mirror"?

Are you looking for brightness at a late hour, when the daylight is fading fast, or even for night-time hunting? Here at Carl Zeiss we have developed the "dielectric mirror" for just such a purpose!

 

The starting point: The roof prism binoculars that are in common use these days use two different prism systems. One is the Abbe-König system, which uses larger prisms. The advantage of this system is the very high level of light transmission. The other is the small and compact Schmidt-Pechan system. However, this system needs an additional reflective surface, which can unfortunately absorb some of the light.

 

In order to achieve extremely high levels of light transmission in a compact format, Carl Zeiss developed a process to apply a reflective coating to the Schmidt-Pechan prisms that produces no light loss. These new "dielectric" mirrors consist of around 70 layers, built up in a high vacuum. The word "dielectric" refers to poor levels of conduction, and describes the vacuum-metallised material. Unlike the metal coatings of conventional mirrors it is non-metallic and therefore does not conduct electricity.

 

For pocket binoculars or lightweight stalking glasses, it gives extremely high values of image brightness and contrast, which means that some of the small optics can make out details astonishingly well, even in the twilight.

 

In practice, the dielectric mirror offers you, the hunter, a marked improvement in brightness in all ZEISS binoculars equipped with this technology.

What is a phase correction coating?

When hunting, it is a definite advantage to have high-contrast images with clearly defined structures. Carl Zeiss has therefore fitted all ZEISS roof prism binoculars with the "P-coating", guaranteeing maximum image sharpness.

Almost all high-quality, modern binoculars are "roof prism binoculars". Compared to the wide "Porro" lenses, they are very sleek in design, and both the incoming and outgoing light rays show little, if any, misalignment. The "space-saving" nature of the design is achieved through ensuring that the incoming light is divided into two bundles, and that both sides of the roof are used twice as reflective surfaces. The precision of these two flat surfaces, the common edge and the 90° angle between them are all hugely significant.

For resolution with maximum detail both roof surfaces are also treated with a special coating. ­This so-called "phase correction coating" prevents wave-like optical effects­­ ("phase shifts") and therefore ensures full clarity.

The phase correction coating was first introduced at Carl Zeiss at the end of the ‘80s, and Carl Zeiss is still a leader in this particular technology, representing exceptional precision.

What are beam splitters and how are they used?

In your ZEISS hunting optics you will find beam splitters in all your laser rangefinders­. They couple the infrared laser light of the measuring beam in and out of the normal light path without influencing the visible light and ensure that the results are clearly displayed in the eyepiece. You do not notice this happening - but you reap the rewards of this technology.

 

Thin coatings on lenses such as the Carl Zeiss T* multi-layer coating prevent reflections. Other coatings increase reflections - through to the mirror effect of the dielectric coating. Different coatings again can split the light, so that, for example, 30% goes through and 70% is reflected. In the ZEISS Victory PhotoScope a "beam splitter" is used to divide the light between the eyepiece and the built-in digital sensor.