You can see the difference between a good lens and a cheap lens at the first look, even if specific values such as twilight factor appear to be the same in products of the same size. Lenses with higher levels of light transmission bring you clear, bright images, while cheap products produce images that are dark and dull. The key factor is how much light is "swallowed up" by the lenses, and therefore fails to reach the eye of the observer. As the genius and ZEISS scientist Alexander Smakula realised some 80 years ago, 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 as much as 50% or more. 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 significantly improved levels of light transmission. Binoculars and riflescopes with this "Transmission layer" were, from that point on, given the designation "T", and the improved multi-layer coating developed at the end of the 70s was named "T*”. For us, "ZEISS T*" is a core skill, and one that we are constantly developing. For you, Smakula's discovery means bright, high-contrast images with no distracting reflections.