In addition to the T* anti-reflection coating, a further protective coating is deposited on the outer surface of the lens elements exposed to the weather on all ZEISS binoculars. It ensures that most of the rain water beads-up and drips off, or can be easily shaken off, and that dirt particles and fingerprints adhering to the lenses are very significantly reduced. This facilitates fast, easy cleaning of these extremely smooth surfaces and so reduces the risk of damaging the valuable optics. The namesake and inspiration for the ZEISS LotuTec® coating are the leaves of the lotus flower with their hydrophobic capability.
Comparison between a standard coating and the ZEISS LotuTEC® coating.
Without the LotuTec® coating, raindrops arriving on the outer surfaces of the eyepieces and objective lenses adhere to the surface, due to the attraction between water and glass. The angle at which the edge of the raindrop touches the glass surface is called the contact angle. Strongly adhering drops are rather ‘flat-looking’ and have low contact angles. LotuTec®, on the other hand, allows fewer contact points, meaning the contact angle is very high, the drops become ball-shaped and run off, or can be shaken off. Measurements of LotuTec® show contact angles clearly above 110° which explains its very high effectiveness and far exceeds many other hydrophobic coatings.
Left, with LotuTec®: A large contact angle results in globular water drops that roll off.
Right, without LotuTec®: A contact angle of max. 95° results in water drops that adhere relatively strong.
The same high standards and test methods used to guarantee the durability of T* coatings for decades are applied to determine the durability and resistance of the LotuTec® coating to abrasion.
The LotuTec® coating was originally developed at ZEISS for eyeglass lenses, where it has proven its value for many years. Special modifications enabled the transfer of this sophisticated coating technology to the high-quality glass used in ZEISS sports optics products.
All products from the ZEISS Victory series are equipped with LotuTec®
Comparison between a standard coating and the ZEISS LotuTEC® coating.
Without the LotuTec® coating, raindrops arriving on the outer surfaces of the eyepieces and objective lenses adhere to the surface, due to the attraction between water and glass. The angle at which the edge of the raindrop touches the glass surface is called the contact angle. Strongly adhering drops are rather ‘flat-looking’ and have low contact angles. LotuTec®, on the other hand, allows fewer contact points, meaning the contact angle is very high, the drops become ball-shaped and run off, or can be shaken off. Measurements of LotuTec® show contact angles clearly above 110° which explains its very high effectiveness and far exceeds many other hydrophobic coatings.
Left, with LotuTec®: A large contact angle results in globular water drops that roll off.
Right, without LotuTec®: A contact angle of max. 95° results in water drops that adhere relatively strong.
The same high standards and test methods used to guarantee the durability of T* coatings for decades are applied to determine the durability and resistance of the LotuTec® coating to abrasion.
The LotuTec® coating was originally developed at ZEISS for eyeglass lenses, where it has proven its value for many years. Special modifications enabled the transfer of this sophisticated coating technology to the high-quality glass used in ZEISS sports optics products.
All products from the ZEISS Victory series are equipped with LotuTec®
