Kowa Prominar TSN-55A Review
The best backpacking spotter is the one you have with you. Having gone on many backpack hunts with an 85mm spotter, the size and weight can be a bit much to bear. Occasionally, I pulled the spotter out of the pack and left it in the truck. Not every hunt is glassing intensive, like archery hunting elk in the deep timber. More than once on hunts like that, I came to regret leaving the spotter when the sudden necessity of long-distance observation arrived. Many years ago, I solved this problem with a subcompact spotting scope. Something so small and light that I take it with me every time. I soon learned that tiny spotters can also be stabilized on smaller tripods and resist shaking from wind better.
I’m not alone. Many hunters made the same decision, and tiny spotters like the Nikon ED50, Vortex Razor 50, and Minox MD50 started showing up at glassing spots across the West. These little spotters had some optical compromises, but they were useful for the occasional need for higher magnification than a binocular would provide.
Original Kowa TSN-550
Kowa reset the market with the original TSN 550 Series spotters. These spotters incorporated all the top “Prominar” technology from their full-size siblings, including a fluorite crystal objective element. The compact spotter was matched with a small zoom eyepiece that provided a good magnification range of 15x-45x but a limited field of view (FOV) throughout that range. Still, that limited FOV had excellent optical performance.
Swarovski ATC
Austrian optics giant Swarovski took up the challenge and introduced their premium 56mm spotter, the ATC/STC. It is based on their accomplished ATX/STX wide-angle eyepiece, which provides 17x-40x magnification with an enormous field of view throughout the range.
The New Kowa TSN-55A
Now, we find Kowa returning fire with a revamped TSN 55 Prominar spotting scope, which has an eyepiece apparently based on their own high-performance wide-angle eyepiece, the TE-11WZ. See it here.
With the new eyepiece, the biggest complaint about the original TSN 550 was solved. The FOV of the new TSN 55 was ultra-wide and almost identical to that of the ATC.
It was only natural to put the two sub-compact spotters next to each other and compare their performance in testing and in the field.
Specifications
Note: I measured the scopes on my kitchen scale without their respective lens covers for the weights.
Kowa 55A Swarovski ATC
- Length 10 in. 10.2 in.
- Weight 2 lb. 2.2 oz. 2 lb. 3.9 oz.
- FOV (@ 1000 yds.) 192 ft. – 105 ft. 186 ft. – 102 ft.
- Price $2299 $2569
Build and Ergonomics
As with earlier Kowa/Swarovski spotter comparisons, the first big difference between the scopes is the rubber armoring. That is … the Swarovski has it and the Kowa doesn’t … mostly. Like the newest large spotters from Kowa, the new 55 has a small amount of armoring around the focus knob area, which is the most frequently touched part of the scope.
Like most other subcompact spotters, both the Swarovski ATC and Kowa Prominar 55A do NOT have a rotating collar. For this reason, I find a ball head a good match for these types of spotters if using a window mount or in other situations where tilting the scope is needed.
The 55A has an extending integrated sunshade that efficiently helps reduce glare when glassing towards the sun. The ATC doesn’t have a sunshade, per se, but the objective lens is recessed enough to work like a non-extending integrated sunshade. I found glare was rarely a problem with either scope.
The ATC has a helical focus adjustment at the center of the body.
The Kowa 55A has an excellent dual focus knob with a fast and slow focus adjustment.
As I have noted in other reviews, I get along fine with either system but find the dual-focus a little quicker and easier to get critical focus.
Resolution
I compared both scopes’ close-range resolution in stable morning air conditions. The test target was a Zeiss Optics Resolution Card with a standard 1951 USAF resolution target. I like this card as the colored portions can provide some comparisons of contrast and color fidelity.
I attempted on three separate occasions to determine which scope resolved better at 40x, but in the end, I just couldn’t. Both scopes provide similarly impressive resolution levels and resolve the same element on the chart.
For the long-range comparison, I went to a mountain canyon near my home and set an 8X11 eye chart at 535 yards. The conditions were sunny with varying amounts of mirage. The mirage made for quite a bit of disturbance, but once again, when the air conditions allowed, I could clearly resolve the same line on the chart with both scopes.
It became apparent that resolution would not be the differentiator for these two tiny spotting scopes.
Chromatic Aberration
Chromatic aberration (CA) is an optical aberration that causes “color fringing” around high-contrast areas of the image. These two scopes are well corrected for CA, with no sign of fringing at the center of the field.
NOTE: These digiscoped photos are for showing color fringing only. Do NOT make conclusions about sharpness from these photos.
Near the edge, both scopes started to show more fringing, with the Kowa 55A showing less than the Swarovski ATC.
NOTE: These digiscoped photos are for showing color fringing only. Do NOT make conclusions about sharpness from these photos.”
Other Optical Performance
When I recently compared the Kowa 66mm Prominar to the Swarovski 65mm scopes, I noted the Kowa tended to have a little more contrast compared to the Swarovski. However, among the subcompact offerings, I really feel these two scopes were similar in contrast, showing rich and detailed colors.
The 55A and ATC had minimal pincushion distortion throughout the magnification range. Starting at the lowest 17x power.
Again, at 40x, distortion levels were similarly low.
Field of View
The listed field of view (FOV) specifications for these two scopes show they should have similarly wide FOVs, with the little Kowa providing just a few extra feet at 1000 yards, both at the lowest and highest magnification settings. In field use, this difference was essentially meaningless, and both scopes provided giant FOVs. The above distortion photographs also demonstrate similar fields of view.
The previous Kowa Prominar 553 model’s narrow FOV was the primary complaint about that scope, especially after the introduction of the Swarovski ATC. The new 55A’s excellent wide-angle eyepiece resolves this issue completely compared to the ATC.
Low Light Performance
Much like the daylight resolution testing, lowlight evaluation between these two scopes was an exercise in frustration, given the close performance between the two scopes. Going to and from one scope to the other repeatedly in the waning light, it was just impossible to choose a winner. Both scopes are squeezing out the maximum performance from their subcompact optics.
Digiscoping
In my previous review of the ATC, I noted its suitability for digiscoping. The new Kowa follows suit here as well, providing a very digiscoping-friendly wide-angle image with good eye relief.
As a bonus to current Kowa Prominar owners, the new eyepiece has the same eyepiece dimensions as the bigger Kowa scopes with the TE-11WZ eyepiece. The new scope will accommodate most digiscoping accessories those hunters already have for their full-size Kowa spotters.
Conclusion
The results of this comparison are perhaps unsurprising. Two of the best optics manufacturers on the planet put their best optical technologies into subcompact spotters. They succeeded in bringing hunters two amazing options for detailed long-range observation in tiny packages. While the Swarovski ATC costs a little more to purchase, the choice between the two for most hunters will come down to preference in focusing knob and/or rubber armoring. Order your Kowa TSN-55A here.
Kowa Prominar 55A is remarkable. It improves on the older 553’s already great performance by greatly expanding the field of view and providing a much easier viewing experience. It is sharp, bright for its size, and sturdily built. Hunters wanted the 550 with a wider field of view, and Kowa delivered.
Hunters who already have a full-size Kowa Prominar with the TE-11WZ eyepiece will appreciate that they can use their current digiscoping accessories with the 55A as well.
Backpack hunters have never had it so good in tiny spotters.
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