Good day everyone -- am new here, though have been a lurker for a while. Writing this to get my thoughts off my chest -- hopefully someone will find this useful.
Intro
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Today I received the Swarovski NL 10x42 and thought to share my impressions, comparing it with the Kowa Genesis 8x33 I also own. Three months ago I thought I would never own a Swarovski, but something kept bugging me in the back of my head, which led to extensive research, and at some point I figured I am wasting so much time reading and watching online reviews that I probably already wasted more time (time is money!) than the ludicrous asking price of the NL Pures -- which means I might as well get the vaunted "best binocular in the world" and get over with it.
First things first -- yes, I am comparing an "alpha" (whatever that means) binocular with one that has been called "alpha-minus". Yes, the magnification is different. Yes, the objective diameter is different. However -- the exit pupil diameter is similar across these two, and both are what one might call great birding binoculars.
First impressions
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I suppose I have been spoiled by the Kowas because I did not experience a "wow" effect holding up the Swarovskis to my eyes for the first time. They are very good, mind you, and better than the Kowas in most regards. Not sure why I expected the "wow," perhaps it's me spending too much time reading online reviews. The picture is slightly larger (as expected with 10x power), and the field is slightly wider. After several minutes holding up one binocular after the other, I started noticing that the Swaros have slightly more contrast. But one would expect that for nearly 3.5x the price (I got a very good deal on Kowas)! After more than an hour of viewing, I noticed that the Swaros may be rendering color more clearly (the Kowas appear to have a very very slight yellowish tint to them -- only visible in comparison to the Swaros, never noticed it before otherwise). But the color difference is so slight I could be fooling myself here.
Optics
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Sharpness: Both binoculars are very sharp. I see slightly more detail with the NLs, but one would expect that with higher magnification.
Contrast: This is one area where I am very pleased with the NLs. The Kowas are not low-contrast bins by any means, but the Swaros edge them out here. I heard the NLs are also more contrasty than the ELs. This makes me think that the Kowa Genesis series may have been a lot closer to the ELs in performance than commonly mentioned. The better contrast, together with the wider field, together with the more comfortable eyecups, results in a more immersive viewing experience with the NLs.
Color rendition: I am pleased with the rendering on both binoculars. I suspect that the NL colors are more "true to life" and that the Kowas have a barely-perceptible yellowish tint to them that somewhat affects overall color rendition, making colors slightly (very slightly!) more difficult to distinguish. But whatever yellowish tint there is in the Kowas, it is so weak that I would have never noticed it without buying the NLs and spending hours peeping through both side by side. Even after writing this, I feel the need to reiterate just how small the color difference is -- small enough that I could well be fooling myself.
Field of view: The NLs are supposed to have the best field of view in the business (aside from Nikon WX). But I was surprised that I did not exclaim "wow" looking through them. Perhaps this is the effect of taking technology for granted. The NLs have 7.6-degree FOV (incredible for a 10x) which turns into a 70-degree apparent FOV according to Swarovski. The Kowas have an 8-degree FOV, which means probably something like 63-degree apparent FOV (note that Kowas actual magnification is closer to 8.2x, if we are to trust AllBinos' measurements). So yeah, 70 degrees is better than 63, and it works well with the high contrast on the NLs to produce a more immersive image in comparison to the Kowas. However, besides the immersive effect, the large FOV is not as useful as I thought it would be because I cannot scan all the way from the leftmost edge to rightmost edge with my pupils. If I do attempt to scan with the pupils, I get "kidney bean" blackening (this happens with both binoculars, but is more pronounced with the NLs because of the larger FOV). So I am effectively limited to the center of the image. Now I would rather take the optics with the larger FOV because, when spotting animals, one can still detect movement using peripheral vision (and then re-center as needed). But the benefit of the gigantic FOV is smaller than I initially thought. This might be less of a problem with the 8x42 NLs which have a larger exit pupil and potentially allow for easier pupil-only scanning. But I haven't tried those myself, so I can't vouch for this.
Chromatic aberration: There is zero CA in the center in both binoculars. If you look off-center, you can induce CA in both binoculars by looking at any high-contrast edge (like the edge of a building lit up by the sun). And once you see CA, it actually appears more objectionable in the NLs, where it shows up as a relatively pronounced blue "blooming" effect. By comparison, the induced CA in the Kowas appears as a muted purple line, thinner than in the NLs and therefore less objectionable. Because both binoculars are nearly perfect in the center, this is not a huge deal to me. But one would expect zero CA for the amount of money Swaro is asking for the NLs! Now the NLs are known to be better in false color correction than the ELs. This again makes me think that the Kowa Genesis series was actually a closer match to the "alpha-level" ELs than it was widely known.
Low light performance: I do not see a big difference after dusk (it may be interesting to repeat this test somewhere where there are no city lights). The Swaros feel very slightly brigher, but that could just be due to their somewhat better contrast rendition. As expected with the 10x, I do see slightly more detail with the Swaros.
Rolling ball effect: The Kowas do have it (it doesn't bother me too much, however). The NL barely has it, if at all. So for all the rolling-ball-effect haters out there who were hesitant to splurge on the NLs because historically Swarovski has been bad on this matter: you can safely go ahead and buy the NLs.
Flare: Did not get a chance to evaluate.
Build quality
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Superb in both, slight edge to the Swaros. The Kowas actually feel like a $2000 bino rather than a $1000 bino. One reason the Kowas feel expensive is because of the metal focus wheel. However I actually hate metal focus wheels and find the Swaro wheel more usable (with one caveat, see below). The Kowas are also "overbuilt" and are heavier than they should be. I expected to be disappointed by the weight of the NLs, but they did not feel very heavy to me, at least compared to the overly heavy 33mm on my hands. Perhaps some of it is due to the "waist" trick or due to front/rear center-of-mass balancing.
Usability
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Design: I think the NLs are a masterpiece of product design and believe they will end up in the MoMA eventually. I have not been a big fan of the EL design by comparison -- while they were a breakthrough design at the time, to me they look like two cucumbers stuck together. But even with the NLs, there is a caveat. The "wasp" waist has the effect of forcing my hands to the middle of the objectives. Now, if both of my hands are in the middle and those objectives are as slim as they are in the NLs, then my thumbs end up rubbing against each other, which is uncomfortable. And I don't even have very large hands! Aside from this, I am impressed by the NLs. The "waist" makes them feel much slimmer than they really are.
Focus wheel: The focus wheel on the Kowas is metal, while on the Swaros it is plastic. I actually like plastic! It feels more grippy to me than metal does, and it doesn't confuse my brain into thinking I am touching sandpaper. The focus wheel on the Kowas is too stiff (difficult to twist while holding with one hand). On the Swaros it feels just right, making the binos much easier to operate with one hand. However there is slippage in the NL wheel -- it is somewhat loose. You need to turn it a degree or so before the focus actually starts changing. By contrast, the Kowas have zero slippage. Their focus starts changing even if you move the wheel a hundredth of a millimeter. This is a minor gripe, but again, for the ridiculous price of the NLs one expects perfection!
Eyecups: I like the eyecups on both binos, with slight edge to Swaros. I am not sure the 6 or 7 positions on the NLs are really necessary. The tactile stops (they make little "click" noises!) on the NLs are lovely, while Kowas feel stiff. Not a real problem, however. The viewing comfort with the NLs is slightly better than with the Kowas, and this is at least partially due to eyecup design. Not that the Kowa eyecups are bad, they are good actually. But the NL eyecups feel very slightly more comfortable. Perhaps it's because they are wider.
Diopter: Some complain about the NL diopter not having a lock and that it is possible to shift it using the index finger. Well, those people must have three-inch-wide index fingers. No problems for me there. Other people claim that central diopter adjustment is superior, since most Euro optics use it. Again, I see little advantage to having it there. I find the right-objective diopter on the Kowa to be acceptable as well. No issues here with either optic.
Straps. Not sure what to think of the Field Pro system on the Swaro. Perhaps I will have a better opinion after using it in the field. For now, it seems like over-engineering to me.
Conclusion
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Modern glass is very good. Differences between tiers are getting smaller. Even a breakthrough like NL doesn't pull away that much, though it is arguably the best portable binocular released so far by anybody. I will probably have more thoughts after testing the Swaro in the field (I have only been with the Kowas in the field, and had no complaints aside from somewhat stiff focus wheel). The NL Pures do provide a more comfortable viewing experience, but almost feel like an incremental upgrade over the Japanese bins. Luckily, money was no object for me here, but I can see not wanting to splurge 250% more for something like less than 50% subjective improvement.
