What makes the Kowa PROMINAR TSN-66A's fluorite crystal objective lens superior to standard glass?
The pure fluorite crystal used in the PROMINAR TSN-66A has exceptional optical properties that virtually eliminate chromatic aberration (color fringing). This results in a significantly sharper, higher-contrast image with true-to-life colors, allowing you to see fine details that would be lost in a scope with a conventional glass lens.
How does the dual focus system on the TSN-66A work?
The TSN-66A focus knob has a two-step mechanism. The quick focus brings an object that is well out of focus into focus 3 times faster than the fine focus, covering 6 m to infinity in two revolutions. The fine focus is for making precise, minute adjustments to achieve critical sharpness, which is essential at the higher end of the 25-60x magnification range.
Is the Kowa PROMINAR TSN-66A suitable for digiscoping?
Yes, it is an excellent choice for digiscoping. The TSN-66A features a dedicated accessory collar that allows Kowa's digiscoping adapters to be threaded directly onto the scope body. This creates a stable connection for a camera, which is critical for capturing sharp images and video at high magnification.
What does the angled body of the TSN-66A mean in use?
On the TSN-66A the eyepiece sits at an angle to the main body. Kowa also makes the straight TSN-66S ZM SET with the same 66 mm fluorite crystal objective, dual focus and TE-11WZ II eyepiece, so the choice comes down to the viewing position you prefer.
Can I use eyepieces other than the included TE-11WZ II with the TSN-66A?
Yes. The TSN-66A body is compatible with several Kowa eyepieces, including the TE-80XW for a wide-angle 35x view and the TE-20H long eye relief eyepiece. You can also use the TSN-EX16 1.6x extender, which increases the TE-11WZ II zoom range by 1.6x, for very long-distance observation.
How does the 66mm PROMINAR TSN-66A perform for birding in low light, such as at dawn?
Kowa does not publish low-light figures for the TSN-66. Its pure fluorite crystal objective virtually eliminates chromatic aberration and PROMINAR lenses and prisms receive multiple layers of coatings, which helps keep colors and markings true. A larger objective such as the 88 mm TSN-88 gathers more light when light is poor.
What is the primary difference between the Kowa TSN-66A and the larger TSN-88A PROMINAR?
The main difference is the size of the objective lens: 66mm for the TSN-66A versus 88mm for the TSN-88A. The larger 88mm lens gathers significantly more light, resulting in a brighter image. However, the TSN-66A is considerably more compact and lighter (2.50 lb), making it a much better choice for those who prioritize portability and travel.
How do I attach a 72mm filter to the PROMINAR TSN-66A?
The housing around the objective lens has a built-in 72mm filter thread. Kowa's manual states that this filter thread allows various types of filters to be screwed onto the front of the scope. Kowa makes the TP-72FT 72mm protection filter for the TSN-66.
Is the 25-60x magnification of the TSN-66A powerful enough for observing distant wildlife?
Yes. The 25-60x range suits most wildlife observation. You can use the lower 25x power to scan a wide area and locate animals, then zoom in to 60x to see fine details. The optical quality of the PROMINAR lens ensures the image remains sharp and clear even at maximum magnification, making it well suited to identifying distant birds of prey, mountain goats, or other remote subjects.
Is the Kowa TSN-66A fully waterproof?
Yes. Kowa states that the TSN-66 PROMINAR has a fully sealed outer body and is 100% waterproof and nitrogen-filled, making it impervious to the elements.
How should I clean the objective lens on my TSN-66A without damaging it?
First, use a blower, compressed air or a soft hairbrush to remove any loose dust or grit. Never wipe a lens before doing this, as grit can scratch the coatings. Then gently clean the lens with a light circular motion using an optics cleaning cloth, gauze or cleaning paper. Commercial lens cleaners can leave a film on the lens surface, so use only the smallest possible amounts.
What does the Kowa Limited Lifetime Warranty cover for the TSN-66A?
The warranty covers defects in materials and workmanship for the lifetime of the product to the original owner, provided it was purchased from an authorized North American retailer. It does not cover damage from misuse, unauthorized repairs, or normal wear and tear. Lens caps, cases and straps are covered for their lifetime but not for accidental loss. Kowa requests product registration within 30 days of purchase.
