Begone, reflections: Zeiss explains the science behind its famous T* coating technology


posted Wednesday, April 13, 2016 at 3:29 PM EDT


Just about every modern lens has something in common: The use of anti-reflective coatings which allow the complex, element-rich optical formulae we take for granted today. Perhaps the key pioneer in the field was Ukranian physicist Alexander Smakula, who invented the first interference-based anti-reflective coatings in 1935, while working for German optics icon Carl Zeiss. (Does that mean you can claim your lenses have a little bit of Zeiss in their blood? Well, we'll leave that call up to you!)

One of the best-known such coatings, not surprisingly, is Zeiss' legendary T* which can be found emblazoned in red print on the front of the company's lenses. But where did that name come from, how was the tech developed, and how exactly does it work? If you want the answers, you'll find them in a just-published article on the company's website.


In the piece, authored by Zeiss' Dr. Vladan Blahnik (Staff Scientist in the company's Consumer Optics Division) and Dr. Benjamin Voelker (part of the optical design team, also in the Consumer Optics Division), you'll find the answers to all of these and more. A whole lot more, in fact, if you jump across to the extremely in-depth 75-page PDF document which gives an even deeper dive on the topic. If you're the technical type, you'll want to pour yourself a coffee, prop your feet up and block out the rest of your evening for this one, because it's in-depth -- and very interesting -- reading.

What does Zeiss' T* coating do for your images? Well, this photo was shot with a T*-coated optic...

We'll leave the bulk of the explanation to the experts at Zeiss, but for those of you with a gentler curiosity on the topic, we'll save you the jump and answer the meaning of the T* brand. It's simply a contraction of how these anti-reflective coatings were originally described, based on the task they performed. The coatings were applied to reduce reflection, or in other words to increase transparancy of the glass beneath -- and so they were called "transparency optics", or "T-optics" for short. And so the t* brand hints at that original name -- a multi-layer coating made from multiple transparency optics coatings. Pretty simple, really, but we must admit we'd never wondered about the source of the name until we stumbled upon the answer.

...and here's the same scene shot with an otherwise-identical optic which lacks T* coatings.

For the rest of the article, hop on over to the Zeiss website. (And don't forget to read the PDF document too, if you want an even deeper understanding of how these clever anti-reflective coatings would work. It's well worth the read!)