Kowa TSN 66 Review | Best Spotting Scope For Hunting?

When it comes to finding the best spotting scope for hunting, a lot of factors come into play. The Kowa TSN 66 Prominar spotting scope exploded onto the market in 2023 with a lot of hype—and for good reason. Why? Well, Kowa Optics has been gaining traction in the hunting space due to its incredible performance and lightweight design. But are the supposed “upgrades” of the Kowa TSN-66 spotting scope enough to move the needle compared to the already standout Kowa TSN-773, which has been one of our favorites?

We were able to get our hands on an early, pre-release version of the Kowa TSN-66 and put together the video below. However, we held off on writing this article until now so we could see how it performed in the long run.

Check out our MASSIVE SPOTTING SCOPE REVIEW where we lined up 19 of the best spotting scopes we could find and put them to the test. All side by side with volunteer testers, no brand loyalties (at least as much as humanly possible), varied lighting conditions, and 14 guys ranking these things. What an awesome project to put together! This review is a product of over two years of work, research, and testing. You don’t want to miss this!

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Kowa Optics: Continuing to Set The Bar

Kowa Optics has become a rapidly growing favorite in the hunting community over the last several years—and for good reason. Bird watchers and nature observers have long appreciated Kowa spotting scopes, but for whatever reason, they hadn’t gained the same traction in the hunting world until recently. As more people have the opportunity to compare Kowa spotting scopes to others on the market, the results speak for themselves.

What makes Kowa spotting scopes stand out from the crowd? In addition to their incredible optical performance, they’re available at a more reasonable price point compared to some other top-tier glass. While Kowa optics are by no means budget optics, their value is among the highest you’ll find. The combination of extremely high value and absolute top-notch performance makes Kowa spotting scopes an easy sell though affording them still isn’t easy.

Best Uses – Who the Kowa TSN 66 Was Built For

Let’s cut right to the chase and lay out who’s going to love the Kowa TSN-66 spotting scope. If you are looking for the best spotting scope for hunting and are someone who can only buy one spotting scope but doesn’t want to compromise on performance, this is the one. If you need a compact spotting scope with the performance of a much larger model—without the weight or bulk—this is your scope.

Here are the best uses I personally see for the Kowa TSN-66:

• All-around use, from deer to elk
• Hunters who need big-spotter performance without the extra weight
• Deer hunting in big, wide-open country
• Elk hunting out West

Times I Would NOT Take the Kowa TSN-66

• When the absolute best low-light performance is needed (e.g., requiring a larger objective lens)

The Testing: Kowa TSN 66 Review

We’ve already tested and documented the incredible performance of the big brothers of the Kowa TSN-66—the Kowa TSN-88 and the even larger Kowa TSN-99. However, our optics testing has shown that just because the larger version of a particular optic performs well, it doesn’t necessarily mean the others in the lineup will perform as well. With that in mind, we’ve been using the Kowa TSN-66 since its release, putting it through the paces on scouting trips, deer and elk hunts, as well as visits to the rifle range and some rifle matches.

Looking for a binoculars? Check out our MASSIVE 26 BINOCULAR REVIEW where we put 26 of the best binoculars side by side!

The Specs: Kowa Prominar TSN 66 Review

The Kowa TSN-66 spotting scope is unique in that it is one of the few mid-sized spotting scopes to offer performance nearly on par with the other Kowa TSN models, while maintaining a weight and usable magnification that, in our testing, have proven to be second to none.

Here are the Kowa TSN-66 specs::

Kowa TSN 66 Specs
Magnification	25-60x
Objective Size	66 mm
Field of View @ 1000 yds	126 ft – 69 ft
Eyepiece Angle	45°
Weight	53 oz
Eye Relief	17 mm
Body Material	100% Magnesium Alloy
Dimensions	15.5″ x 3.5″
Glass	Fluorite Crystal + Kowa XD Lens
Tripod Attachment	Yes – Threaded
Country of Origin	Japan
Current Price	$2,999

The Kowa TSN-66 is one of the lightest spotting scopes in the 65mm class, making it one of the best spotting scope for hunting. Because of that, you might expect some compromises. However, I’m here to say that it absolutely does not. On the contrary, you’ll be hard-pressed to find anything better in its size class than the Kowa TSN-66. Period. The magnesium alloy body helps keep the weight down without sacrificing any performance whatsoever. This incredible spotting scope truly offers the best of all worlds.

Pure Fluorite Glass: Kowa TSN 66 Review

So, why does it matter that Kowa uses a pure fluorite crystal lens? This type of lens is widely considered to produce the best image quality available in today’s optics. Pure fluorite crystal lenses virtually eliminate chromatic aberration while delivering highly contrasted images with exceptional resolution.

Pure fluorite is much more difficult to work with than typical optical glass, making lenses featuring it significantly more expensive to produce— which is why it’s used less frequently. The difference in optical performance, however, is clear.

The Eyepiece: Kowa TSN 99 Review

The Kowa TSN series of spotters now all use the same eyepiece after the introduction of the TSN-66 and the even newer Kowa TSN-55. With this update, Kowa Optics made a few minor but positive updates to the eyepiece. The biggest change is that the new eyepiece offers much more resistance to changing positions, which helps keep it from unintentionally rotating while riding in your pack. Another benefit we found with this new design is that it handles digiscoping with your phone much better, as it will hold your phone in place for those landscape shots if you need to roll the eyecup out a click or two.

Another small change is in the lettering that indicates the magnification for the Kowa TSN-66 and TSN-88, while the larger number is for the Kowa TSN-99 spotting scope. All of the TSN Prominar spotting scopes use the same eyepiece, which makes it possible to buy one eyepiece and multiple bodies if you want to effectively have multiple spotting scopes.

The Kowa Optics Prominar TE-11wz 25-60x Wide Zoom eyepiece is very comfortable, functions well, and provides a very pleasant viewing experience. The eyepiece also has a rubber coating that adds durability and is pleasant to the touch.

We found the zoom mechanism to have the perfect amount of resistance— not so stiff that it moves the optic when you want to zoom in on an object, but not so loose that it rotates unintentionally. The mechanism was very smooth, and there was zero play.

Eye Box: Kowa TSN 6 Review

What is eye box forgiveness, you might ask? Simply put, this refers to how much room for error the optic allows in relation to the position of your eye to the eyepiece. A “narrow” or “unforgiving” eye box requires precise eye placement to get a full field of view. While an unforgiving eye box isn’t the end of the world, it can be frustrating.

Since the Kowa TSN-66 uses the same eyepiece as the Kowa Prominar TSN spotting scopes, we experienced the same forgiving eye box. While eye box forgiveness is something less talked about in the optics world, a forgiving eye box makes a big difference—particularly when glassing for longer periods—and it is noticeable with this Kowa TSN-66.

Magnification Range & Exit Pupil – 25-60x: Kowa TSN 66 Review

Typically, spotting scopes in the 65mm range offer a top-end magnification of 45x. However, the Kowa TSN-66 spotting scope gives you a whopping 25x–60x magnification range. Now, if you’ve ever used a 65mm spotting scope with 60x magnification, you’re probably thinking, “There’s no way it’s very usable.” That logic is usually sound and generally applies to most spotting scopes with a 65mm objective; however, that is absolutely not the case with the Kowa TSN-66. Every bit of that 25x–60x magnification is not only usable but crystal clear.

EXIT PUPIL

The exit pupil is affected by the combination of objective size and magnification and has a direct effect on low-light performance. Let’s take a look at the calculation:
Exit Pupil = Objective size / Magnification

MINIMUM MAGNIFICATION

• TSN 99 – Minimum Zoom: = 99 mm / 30x = 3.30 mm exit pupil
• TSN 88 – Minimum Zoom: = 88 mm / 25x = 3.52 mm exit pupil
• TSN 66 – Minimum Zoom: = 66 mm / 25x = 2.64 mm exit pupil

MAXIMUM MAGNIFICATION

• TSN 99 – Maximum Zoom: =99 mm / 70x = 1.41 mm exit pupil
• TSN 88 – Maximum Zoom: = 88 mm / 60x = 1.47 mm exit pupil
• TSN 66 – Maximum Zoom: = 66mm / 60x = 1.10 mm exit pupil

As you can see, at maximum magnification, the exit pupil size shrinks to less than half of what it is at minimum magnification, so less light can be gathered for the image. Because of this, your smaller objective simply cannot compete with a spotting scope with a larger objective, all other things being equal. That being said, if you put a spotting scope with pure fluorite glass up next to another spotting scope that does not have fluorite crystal glass, you will see a difference in performance, and that smaller objective will hold its ground fast—and potentially even outperform a spotting scope with a larger objective, as we observed.

Dual Focus System: Best Spotting Scope For Hunting

We have thoroughly documented how much we love the dual-focus system of the Kowa spotting scopes. Bottom line: during our testing, we’ve found the following benefits:

• Easier to resolve the image
• Introduces less vibration/shake than a barrel focus system
• More ergonomic feel

The most significant benefit is the ability to fine-focus without introducing shake or vibration to the spotting scope.. Bottom line, this focus mechanism design out performs even the best barrel focus mechanism in our experience and personal opinion.

Weight & Body Construction – Kowa 66 Review

The body of the Kowa TSN-66 spotting scope is made from 100% magnesium alloy, making it extremely durable while not adding extra weight. The Kowa TSN-66, like the other Kowa spotting scopes, does not have rubber armor, which is one of the common complaints I hear about Kowa spotting scopes. While I share that disappointment, it is such a minor issue—and one that saves a bit of weight—so the downside is offset by a legitimate benefit. While that rubber armor is nice to the touch and protects the housing, it also adds weight.

Image Clarity/Low Light Performance – Kowa Spotting Scope Review

While a digiscoping photo with a phone never seems to do the actual image quality justice, these pictures give you an idea of the performance of the Kowa TSN-66. These photos were taken during an archery mule deer hunt. From left to right: over 2 miles away at 60x, 500 yards away at 25x, and 1,500 yards away at 60x, respectively.

Keep in mind that you will still face more low-light challenges with this 66mm objective compared to a spotting scope with a larger objective, and you simply cannot expect the same low-light performance from this as you would from the Kowa TSN-88 or TSN-99. Nonetheless, I would (and did) put this Kowa TSN-66 up against many 80mm spotting scopes on the market, and it outperformed many of them.

I also happened to have a now-discontinued Kowa TSN-77 on hand (no pure fluorite glass, but a larger 77mm objective) and compared them side by side in the field while scouting for mule deer. We were watching some bucks just over 2 miles away, trying to resolve enough detail to determine if these bucks were 160-class or 180+ class, which provided the perfect real-world testing conditions.

I found that, even though the Kowa TSN-66 had a smaller objective, the fluorite glass was able to slightly outperform the larger Kowa TSN-77 in both image resolution and color rendition. The differences were very small and only noticeable when viewed side by side, but I also noticed slightly better low-light performance and a bit better color contrast.

Edge-to-Edge Clarity – Kowa Prominar TSN 66 Review

Just like all Kowa Prominar TSN spotting scopes, the TSN 66 provides nearly flawless edge-to-edge clarity, again solidifying it as a the best spotting scope for hunting. This is one of the hallmark features of the highest-quality optics, and throughout our testing for this Kowa TSN-66 review, we were nothing but impressed. There is zero compromise throughout the entire field of view, which is especially impressive given that it is a wide-angle eyepiece with a massive field of view.

Chromatic Aberration – Kowa TSN 66 Review

Chromatic aberration is something that most optics—other than the very best—suffer from. To varying degrees, you can often pick out that fuzzy, hazy, or color-distorted edge on a tree branch, rock shelf, or antler tip at longer distances.

However, we did not notice any chromatic aberration during our testing of the Kowa TSN 66. When detail matters most, and particularly at long distances, chromatic aberration can make the difference between spotting an antler tip or missing that bedded animal.

Field of View – Kowa TSN 66 Review

This Kowa TSN-66 spotting scope gives you an impressive field of view that not many can boast, particularly in the 65mm category. The fact that the Kowa TSN-66 reaches the 60x magnification range while still maintaining a respectable field of view is especially impressive and what you are looking for when searching for the best spotting scope for hunting.

For comparison, it’s worth highlighting the field of view specs of the Kowa TSN-66 spotting scope versus other spotting scopes we have tested:

• Kowa TSN 66 (25-60x66mm): 126 ft – 69 ft
• Swarovski ATS (25-50x65mm): 126 ft – 81 ft
• Athlon Ares G2 (15-45x65mm): 171 ft – 81 ft
• Kowa TSN 883 (25-60x88mm): 138 ft – 76 ft
• Kowa TSN 99 (30-70x99mm): 105 ft – 60 ft
• Athlon Cronus (20-60×86): 117 ft – 60 ft
• Leupold Santium SX-5 (27-55×80): 105 ft – 73 ft
• Meopta Meostar WA (30-60x82mm): 146 ft – 68.8 ft
• Maven S1A (27-55x80mm): 115.2 ft – 83.3 ft
• Sig Oscar8 (27-55x80mm): 105 ft – 73 ft
• Swarovski ATX 85 (25-60x85mm): 124 ft – 68 ft
• Tract Toric UHD (27-55x80mm): 105 ft – 73 ft

Now, keep in mind that each of these have slightly different low and high magnifications. Generally, the lower the magnification, the bigger the field of view, and the higher the magnification, the smaller the field of view gets.

What We liked: Kowa TSN 66 Review

While I wasn’t surprised by the result, the Kowa TSN-66 spotting scope was flat-out impressive. It fills the previous gap in the Kowa spotting scope lineup, being the perfect all-around spotting scope. It’s plenty light to carry around the backcountry, while still providing best-in-class optical performance.

While we loved the extremely forgiving eye box of this spotting scope, the thing that truly set the Kowa TSN-66 apart from its competition is the usable 25–60x zoom range. Even the Swarovski ATS 65mm spotting scope only gives you a 25-50x magnification range.

Here are our most appreciated features of Kowa TSN 66 and why we’ve handed it our “Backwoods Best 65mm Spotting Scope” award.

• Massive field of view
• Incredibly usable 25-60x magnification
• Near perfect edge-to-edge clarity
• Flat field of view
• Superior image resolution
• Superior low light performance
• Smooth zoom mechanism
• Dual focus
• Build quality
• Excellent warranty
• Great overall value

What We Didn’t Like: Kowa TSN 66 Review

After testing for this Kowa TSN-66 review, it was pretty difficult to find much we didn’t love about it. These are being a bit nit-picky, but there were really only a few things we found to complain about:

• Play in coarse focus wheel
• Weight (53 oz)
• Price point

There was just a little play in the course focus wheel, same as we’ve noticed with all the Kowa TSN spotting scopes. Not a huge deal, but I’d love to seem Kowa Optics tighten this up.

The weight of 53 oz isn’t quite as much of a weight savings over the Kowa TSN-77 (59 oz), which the TSN-66 replaced. While 53 oz is still one of the lightest in its class, we were hoping it would come in under the 50 oz mark. Maybe that was wishful thinking.

Finally, with a retail price tag of $2,999 at the time of this writing, it is a significant price jump over the TSN-77, which could be purchased for just over $2,100, and its performance was pretty darn close to the TSN-66.

Kowa Lifetime Warranty

Kowa Optics offers a transferable lifetime warranty. I haven’t needed to test the warranty myself, but it’s good to know your purchase is backed by what I hear is a solid warranty. Be sure to register your purchase with Kowa to be eligible for warranty coverage.

How The Kowa TSN 66 Spotting Scope Ranked

Conclusion – Kowa 66 Review

This Kowa TSN-66 review solidified that this is the spotting scope of choice for us—unless an ultralight option is needed or you require the absolute best low-light performance that a larger objective provides. However, for just about everything else, the Kowa TSN-66 will not only do the job but do it exceptionally well.

If you need elite performance from a mid-size spotting scope, the Kowa TSN-66 is our choice among the options available on the market today. If you can fit this spotter into your budget, you will absolutely not be disappointed.

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