What Makes a PROMINAR Scope So Special?

Manufacturing & Craftsmanship

Soka, Saitama. In this small city near Tokyo, Japanese manufacturing pride runs deep. It is here that PROMINAR spotting scopes are designed, made and tested. Inside the factory, the atmosphere is both tranquil and alive with concentration. This is the Spirit of Takumi.
Observe the eyes of the men and women immersed in their work and you will see an unbroken attention to creating a flawless product.


Producing the ideal optical system begins with perfect polishing. Due to the delicacy of Pure Fluorite Crystal, the majority of polishing is done
by hand with extreme care. Relying on experience and intuition, the expert polishes each lens into a spherical surface to an accuracy of 10-7
(0.0000001) meters. Before being readied for coating, the finished lens undergoes comprehensive inspection.


To control the optical phenomena of refraction and reflection, PROMINAR’s lens and prism receive multiple layers of coatings using technology cultivated from the production of medical retinal camera lenses. Out of tens of millions of possible lens and coating combinations, the ones that will yield the best performance is selected. Dedicated to the spirit of Takumi, Kowa engineers year after year seek ways to improve and develop the coating technology used for PROMINAR lenses.


PROMINAR spotting scopes use an advanced roof-type prism. The advantages include a linear optical path and a more compact scope. Designing a roof prism, however, comes with challenges. First, it requires lens coating and mirror coating to compensate for low reflectivity on certain areas of the prism. What’s more, it requires highly advanced glass processing technology. Even the slightest distortion causes dissonance to the eye.
PROMINAR’s roof prism is such a vital piece of the optical system that its shape is incorporated in the brand logo.


The lens body of most PROMINAR scopes* is made of magnesium alloy widely held to be the lightest practical-use metal. Though the material is difficult to shape and process, Kowa’s expertise using precise machine processing produces highly durable, lightweight bodies that are built to perform flawlessly over time. Once the body is shaved and shaped, the lenses are attached and lubricant applied to each moving part. The expert craftsperson confirms at every step that the scope meets Kowa’s standards of perfection.

Quality Control

Testing the optical performance falls to the factory’s most skilled and experienced expert, who uses exclusive technology and skills honed and passed down over generations to determine whether the finished scope is worthy of the PROMINAR name. Each scope is put through a series of stringent tests. If it does not meet his uncompromising standards, it won’t go to market.
Kowa’s manufacturing system is based on the spirit of Takumi. Every day a further step ahead. Another innovation that makes PROMINAR spotting scopes feel and perform like a natural extension of the hand and eye.