From the Founder of Kaenon: basn5 and Tajima Lens Technology
The next evolution of polarized lens and frame technology
Steve Rosenberg founded the Kaenon sunglass brand in 2001, and created and co-invented the polarized lens technology Kaenon sold as SR-91. Today, Steve and his son Jacob Rosenberg have evolved and improved that lens technology into Tajima Polarized Lens Technology. It is exclusively available through Tajima-Direct.com and in basn5, their new advanced sunglass line.
Last month, as a sponsor of the Rolex Big Boat Series in San Francisco, Tajima Direct and basn5 were set up and presenting on the waterfront. Sailor after sailor walked by wearing Kaenon, most in pairs ten or fifteen years old or more. Very few of them knew that the person who created that lens was standing under our tent. So here is the story, for the record.
Where it started
Steve founded Kaenon in 2001, after eight years at Oakley. He wanted to improve on what he had been using during his time at Oakley. At the time of launch, Kaenon set a new standard in active performance frame design, but the real breakthrough was the lens. Steve invented a polarized lens technology that became the SR-91: SR for Steve Rosenberg, 9 for the nine elements in the lens, 1 for the first of its kind. It became the lens competitive sailors relied on to read wind on the water, and many of them still do as the legacy Steve created lives on.
Steve and his partners sold Kaenon in late 2015. The Kaenon and SR-91 names are trademarks, and they went with the sale. The lens technology and supply network remain with Steve and his Japanese lens partners who produce it.
The lens kept evolving
After the sale, Steve kept working with our lens-making partners in Japan to refine the technology: sharper detail, richer color saturation, greater durability, longer lifespan. Today it carries the name Tajima, after the small town in Japan where our patented Tajima Urethane™ lens material is made. It comes from the same lineage, with ten more years of development, and it’s available only through Tajima Direct and basn5.
Tajima Direct: any frame, any brand
Jacob grew up around this lens in, what he calls, “a sunglass household”. While he was at Stanford University, he asked Steve a simple question. Why should a lens this good be locked inside one brand? Why not make it available to anyone, for any pair of sunglasses? Steve agreed.
Jacob then spent his final two years at Stanford building that idea into Tajima-Direct.com. As his graduation approached in spring 2020, Covid shut the world down. Steve and Jacob saw that the premium lens service answered what people needed in that moment, and they launched Tajima-Direct.com in March 2020. Tajima Direct puts Tajima polarized lenses, prescription and non-prescription, into any dual lens sunglass frame, from any brand, for anyone.
basn5: the frame, rethought
Six years of Tajima Direct have put nearly every frame from every brand across our lab bench, and we’ve seen exactly what wears out and fails. This summer, after years of requests, research and development, we released basn5, our advanced sunglass line. It is built from a single high-performance material, with new construction technology and fresh design language that renders incredible surface detail with a tactile matte finish. Most importantly, uncompromising vision with the latest generation of Tajima polarized lenses in both prescription and non-prescription. basn5 is available at basn5.com and Tajima-Direct.com, with a wide range of Tajima lens options.
The lens, improved
Tajima Urethane lens technology gives you the optics of glass in a lens that is shatter-proof, impact-resistant and 5x more durable than polycarbonate and nylon and the lightest weight polarized lens on the market. Validated and verified by independent optical testing performed by Colts Laboratories. This evolution has brought sharper detail, richer color saturation, and longer life on the water and off.
In any frame, including prescription
Through Tajima Direct, we put our lens technology into any frame, from any brand. Every lens is custom-cut in our lab in Huntington Beach, California. Tajima-Direct.com is the only source for genuine Tajima Urethane™ polarized lenses in both non-prescription and prescription. All custom cut into your specific frame, or basn5 in our digital lab here in California.
Build a better frame: basn5
Eight years at Oakley, fifteen years building Kaenon, and six years of seeing every frame from every brand come through Tajima Direct taught us what fails on a pair of sunglasses. We built basn5 to solve those problems.
| What we learned at Kaenon and Tajima Direct | How basn5 answers it |
|---|---|
| Paint peeling | No paint. The color is in the material, so there’s nothing to peel or chip. |
| Hinge failure | Patent-pending stacked hinge architecture, made with an elite Austrian hinge maker. Strong, precise, serviceable. |
| Rubber components breaking down | No rubber. The frame material itself is grippy, with nothing added to break down or peel off. |
| Parts you couldn’t replace | Every part is serviceable. |
Light. Comfortable. Durable. The frames are engineered in Germany from one advanced material, with fit you can adjust at the temple tips. Highway 1 and Fort Point weigh 19 grams; Davenport, 25 grams.
Every basn5 comes standard with Tajima polarized lenses, and every frame is available in prescription: Highway 1 ($365), Davenport ($395) and Fort Point ($395).
Try the next evolution: basn5
basn5 frames with Tajima polarized lenses, non-prescription or prescription.
Shop basn5 sunglasses with Tajima lenses → · The frame story on basn5.com →
Still wearing your Kaenons?
If you still trust your old frames, we’ll fit them with the latest Tajima lenses, prescription or not.
Start here: Tajima replacement lenses for Kaenon → · Prescription lenses for Kaenon →
Put this lens into any frame you already have.
Any frame, any brand. Polarized or prescription, custom-cut and installed in our Huntington Beach lab.
Steve Rosenberg: background
- A top amateur and professional sailor, US Sailing Team
- Eight years at Oakley before founding Kaenon full time, 15 total
- 2001: Founded Kaenon
- Invented the polarized lens technology marketed by Kaenon as SR-91
- November 2015: Kaenon sold
- 2016–present: Continued developing the lens technology with Japanese lens partners; now Tajima Urethane™ and Tajima Polarized Lens Technology
- 2020: Co-founded Tajima Direct with Jacob Rosenberg
- 2026: Co-founded and launched basn5 with Jacob Rosenberg
Kaenon, Tajima and basn5: quick answers
Who founded Kaenon?
Steve Rosenberg founded Kaenon in 2001 and invented his namesake SR-91 (Steve Rosenberg, 9 elements, 1st of its kind) polarized lens with his Japanese lens partners. Only trademarks were sold to Kaenon in 2015, not supply. Steve and his son Jacob founded and lead Tajima Direct and basn5.
Are Tajima lenses the same as Kaenon SR-91 lenses?
Tajima lenses are made from patented Tajima Urethane in our lens-making facility in Tajima, Japan. The lens source and quality of the Kaenon SR-91 lens cannot be corroborated or confirmed from 2016 and beyond, after Rosenberg sold the Kaenon brand and trademarks. The only source for authentic Tajima Urethane polarized lenses in prescription and non-prescription is Tajima Direct.
What is basn5?
basn5 is our advanced sunglass brand, launched in 2026 and built around Tajima polarized lenses. Every frame is available in prescription.
Can I put new lenses, including prescription, in my Kaenon sunglasses?
Yes. Tajima Direct custom-cuts and installs new Tajima polarized lenses for any Kaenon frame (or any other brand’s frame) in prescription or non-prescription. Tajima replacement lenses for Kaenon · Prescription lenses for Kaenon.