Steve C
Well-known member
OK, bear with me. I decided to post a three way review here. The Kowa and ZEN ED stuff is duplicated, but I think this might be easier than going back and for the between two threads. So I apologize for the duplications. I added several pictures below. EDIT at least I tried. I got two and had some connection problems. SO I think the two I uploaded first will show. I'll add more in another post
The Kowa Prominar TSN 884
This is the first of these I have had the opportunity to use. The objective is a doublet, with one element being fluorite glass. It also simplifies design as it removes the need to use a triplet arrangement with two ED elements.
I will say right up front that if this scope does not suit you, you are likely beyond help. As far as strict resolving ability, great contrast, and bright, flat images with sharp to the edge performance…there is NO edge distortion, none. I have a hard time imagining anything bettering it. I started trying HARD to find something wrong with this scope after I looked it over a little. I didn’t find a single thing I can even nit pick about. I suppose other alpha level glass will equal it and there are individuals who may prefer some other brand for color bias, eye relief, ergonomic factor, or some other user perceived factor, but the optics are likely as close to state of the art as can be gotten into a spotter as of now.
A quick check of prices shows the body of this spotter available for around $2,500 US. The TE-10Z 20-60 eye piece is about $500 US. There is a wide angle fixed 30x and a 25x LER eyepiece available. So that is obviously a chunk of change and this is certainly an outstanding optical instrument.
This is a little shorter than the ZEN ED, at 13.5 inches, and weighs 53.6 oz. EDIT: Without eye piece, sunshade retracted.
The Zen Ray ZEN ED 2
This is a new scope from Zen Ray. The current price of this instrument is $1,200 US, comes with a 20-60x eye piece, and a zip on view through removable cover included, so in total is less than half of the price of the Kowa. Zen Ray plans to introduce a 30x Wide angle eyepiece for the ED 2. No information on what it will cost. It bears a similarity to the Kowa, but both are likely forced into physical similarities due to the fact that they are both 80mm plus porro prism spotters. The objective of the ZEN ED 2 actually measures 85 mm, but is stopped down to the advertised 82 mm effective aperture.
The objective is a triplet, two pieces are cemented and air spaced from the third element. There is s fourth lens in the objective group near the tripod mount plate. I do not know which two elements of the triplet are cemented, but I do know that two of the elements are ED.
This is a new scope; the current price is $1,200 US. It comes with a 20-60x eye piece, and a zip on view through removable cover included, so in total is less than half of the price of the Kowa. Zen Ray plans to introduce a 30x Wide angle eyepiece for the ED 2. No information on what it will cost. It bears a similarity to the Kowa, but both are likely forced into physical similarities due to the fact that they are both 80mm plus porro prism spotters. The objective of the ZEN ED 2 actually measures 85 mm, but is stopped down to the advertised 82 mm effective aperture. The scope is 15 inches long and weighs 64 oz. This is with the eyepiece. It is 13.75 inches, sunshade retracted, and 56.0 oz without.
The objective is a triplet, two pieces are cemented and air spaced from the third element. There is s fourth lens near the tripod mount plate. I do not know which two elements of the triplet are cemented, but I do know that two of the elements are ED.
Both the Kowa and the ZR have a dual range coarse/fine focus arrangement.
Theron MAG 82
This is a little different from the other two scopes. It has a center helical, single rate focus collar just ahead of the tripod plate. It looks a lot like the Nikon 82 ED Fieldscope. It also comes with a 25-75x zoom eyepiece and a 30x wide angle as well. The Theron is on a special introductory offer of $950 with both eyepieces. Like the ZEN ED 2 it comes with a removable soft cover, view-through arrangement. Regular msrp is $1,200. The scope is 13.75 inches long and weighs 62.0 oz. EDIT: Also without eye piece and sunshade retracted. Sunshades on all extend about 2.75 inches.
The objective is the more common triplet with two elements cemented and air spaced from the third.
Comparisons
The removable eye piece assemblies are obviously quite a bit different, the Kowa being about twice the size of the ZEN. Both are bayonet style. The ZEN eyepiece, as noted elsewhere, looks like a dead ringer for the Swarovski, but Zen Ray also told me they did not advise interchanging them. The Theron has a threaded eyepiece that looks like a standard threaded style, so there may be some leeway in selecting different eye pieces.
I don’t think the Kowa interchanges with anything else.
The objective designs of all three of these are designed to focus all three (red, blue, green) primary light waves at the same point with the design intent of elimination color fringing and chromatic aberrations.
I suppose the obvious question foremost in most people’s mind is if the ZR spotter is the optical equivalent of the ZEN ED 2 binoculars. As far as I can see, the answer is yes. Ditto Theron. The ZEN spotter seems built better compared to the Kowa than the ED 2 binoculars compare in build to the alpha brands. The actual quality of the physical construction seems virtually equal to the Kowa. The Theron is also very well built, showing no weaknesses compared to the others, so I don’t think that construction will be a concern with any of the three.
The Theron arrived after I had the others pretty well done. So I had a little knowledge of what it had to stand up against. Also I was more careful to be sure not to smudge anything. The first thing that stands out is that the fov with the standard zoom eye piece is narrower than either the ZR or the Kowa. Other than that it stood up very well for itself. The surprise of the review is how good it is over 60x. The Theron, like the others started showing some image drop off by the time the dial hit 50x, but the Theron carried that image to 75x, and was not overpowered by that much magnification.
I have always thought that performance in any spotter started to decline as the exit pupil dipped to less than 2.0 mm. So it is with these much past 40x, although, what there is, is not much. The fall off in all three is about the same between 40-50x, and the Kowa is a little better than both the ZEN and the Theron from 50-60x. The ZEN with a wider fov is a bit easier to keep centered at higher magnification that the Theron. Up to 40x, there is nothing save the ever so slight edge difference, and the somewhat smaller fov of the Theron, that separates these scopes. The Kowa shows a little better brightness over 50x than the others. And the distortion on the ZEN and Theron increases a bit. When I say a bit that is what I mean. Without a side by side you would never know it.
I wish I had 30x WA eyepieces for the Kowa and ZR. The Theron 30x WA is pretty neat. At least twice the apparent size fov of the 25-75 zoom at 30x, and noticeably larger that the 30x setting on the Kowa and ZR. Nice and flat and quite sharp on the edge. I would probably wind up using this as the main use eye piece and switch to the zoom when I found something that 30x wouldn’t handle. An extra eyepiece would not add much weight. The WA should appeal to digiscopers as well. The objectives of the three scopes are somewhat different from each other. The most significant thing you will note is the diameters of the oculars. Typically the fov increases with increase in ocular diameter. The Theron 25-75 has a total outside diameter of 46.66 mm with an ocular lens diameter of 15.75 mm. The 30x WA on the other hand is 52.75 mm and the lens is 31.55mm, or in other words the 30x WA has over four times the glass surface area in the ocular compared to the 25-75. The ZEN is 56mm with an ocular lens of 25mm. The Kowa is 55.5 and 24 mm respectively, both considerably smaller than the Theron WA. The Kowa and ZEN 30xWA will have wider ocular glass as well, but I don’t know what the sizes are.
Now I have admitted I can find nothing to object to or even wish to improve in the Kowa, so how do the ZEN ED 2 and the Theron MAG 82 really stack up? Well the ZEN ED and the Theron are both serious glass and the stack up very well. The ZEN and Theron have a slight amount (very slight) edge distortion. They do not bend any lines at the edge and the little distortion there is will not force the viewer to automatically center an object on the field edge. But side by side, it is a difference. The ZEN may have an ever so slightly warmer color bias than the Kowa. The Theron is maybe a cooler bias than the ZEN. Not better or worse, just a little different from each other.
You can just about forget chromatic aberrations and color fringing in any of these three instruments. I had ideal conditions for it, and I tried and failed to make it show up. There is a large mountain about 5 miles east of me that soars up in the air over 3,000 feet in about a mile. With the bright afternoon sun on that snow white face and skyline against a bright blue sky that view will show CA if it is going to show at all. So will Bald Eagles (six around the place over the last few days) or our Black Angus cattle against a snow background in the bright sun.
A handy stationary evaluation targets was a bright blue cobalt blue sign with white letters. The sign is on the end tower of the neighbors Valley Irrigation Center Pivot. It says “Valley”, below that “8000 series” and the double Valley Irrigation logo off to the side. The larger letters are 4” tall, the smaller are two inches. The double V logo, one V inside another, is 4” tall, with a one inch wide space between the two V’s. The laser rangefinder called that sign 1,115 yards away.
There are two noticeable operational differences. First, the zoom function of the eyepiece is much easier to operate on the Kowa. Whether or not this was a function of design, the very cold weather stiffening the ZEN more than the Kowa, or maybe the Kowa has been used enough that the movement has eased up, I can’t say for sure, but it was noticeable. There is much less movement on top of the tripod when zooming magnification with the Kowa. The Theron’s screw in eyepiece needs to be pretty firmly screwed in or the eye piece will unscrew when you move the power ring. This is a good indication of how tight the eyepiece needs to be. Focus improves as you go from not quite tight enough to just right. I’d like to see the focus collar on the Theron eye piece a little larger in diameter so it is easier to feel. Second is the relative speed of the focus wheel movement. Both are similar in coarse and fine focus wheels and the Kowa has a faster rate of focus than the ZEN, using about half of the movement of the ZEN. It was actually easier to dial fine focus at high magnification, for me anyway, with the ZEN. The problem with the Theron is after it hits 50x, with the single rate focus. The depth of field decreases with magnification increase and it is a lot easier (for me anyway) to use the fine setting of the dual range to dial in your target in the center of the field depth. That problem eased up quite a bit as I used it more and got accustomed to it, but the dual range is mostly easier. That is until you have to wear gloves. Then the big collar is a lot easier to manipulate. I doubt that 75x will get a lot of use, but the extra 15x is there when you need it. Unlike the Kowa or ZR the offset eyepiece is of set to the right making it easier to sight along the top scope body to line up the scope.
Additionally, all three of these spotters are very good with handling glare and in controlling stray light. The Kowa is a little better in both regards. Looking toward bright light in the ZEN, I could move my head around and induce some glare. It was possible, but not so much with the Kowa. The Kowa has a four stop eye piece and the Zen is a threaded on eye cup so it can be adjusted anywhere you like in the range. The Theron is a three stop adjustment. All three worked well enough both with and with out sunglasses.
So, to close this up, is the Kowa a better instrument? Sure it is. Not much doubt of that. I think serious digiscopers would really like that nearly perfect, flat, edge sharp picture. Are there better spotters than the Kowa? Maybe, but truth be told, I’d have to see it for myself. From my perspective, the ZEN or the Theron will do anything most people need done with a spotter. I would be sort of hard pressed to give an account of the difference, but I suppose if I gave the Kowa a 100 rank, the others would be something like 97-98. The differences, while there, are pretty slight and not many will notice without a side by side by side. I’d be plenty happy to take the ZR or the Theron pretty much anywhere.
The Kowa Prominar TSN 884
This is the first of these I have had the opportunity to use. The objective is a doublet, with one element being fluorite glass. It also simplifies design as it removes the need to use a triplet arrangement with two ED elements.
I will say right up front that if this scope does not suit you, you are likely beyond help. As far as strict resolving ability, great contrast, and bright, flat images with sharp to the edge performance…there is NO edge distortion, none. I have a hard time imagining anything bettering it. I started trying HARD to find something wrong with this scope after I looked it over a little. I didn’t find a single thing I can even nit pick about. I suppose other alpha level glass will equal it and there are individuals who may prefer some other brand for color bias, eye relief, ergonomic factor, or some other user perceived factor, but the optics are likely as close to state of the art as can be gotten into a spotter as of now.
A quick check of prices shows the body of this spotter available for around $2,500 US. The TE-10Z 20-60 eye piece is about $500 US. There is a wide angle fixed 30x and a 25x LER eyepiece available. So that is obviously a chunk of change and this is certainly an outstanding optical instrument.
This is a little shorter than the ZEN ED, at 13.5 inches, and weighs 53.6 oz. EDIT: Without eye piece, sunshade retracted.
The Zen Ray ZEN ED 2
This is a new scope from Zen Ray. The current price of this instrument is $1,200 US, comes with a 20-60x eye piece, and a zip on view through removable cover included, so in total is less than half of the price of the Kowa. Zen Ray plans to introduce a 30x Wide angle eyepiece for the ED 2. No information on what it will cost. It bears a similarity to the Kowa, but both are likely forced into physical similarities due to the fact that they are both 80mm plus porro prism spotters. The objective of the ZEN ED 2 actually measures 85 mm, but is stopped down to the advertised 82 mm effective aperture.
The objective is a triplet, two pieces are cemented and air spaced from the third element. There is s fourth lens in the objective group near the tripod mount plate. I do not know which two elements of the triplet are cemented, but I do know that two of the elements are ED.
This is a new scope; the current price is $1,200 US. It comes with a 20-60x eye piece, and a zip on view through removable cover included, so in total is less than half of the price of the Kowa. Zen Ray plans to introduce a 30x Wide angle eyepiece for the ED 2. No information on what it will cost. It bears a similarity to the Kowa, but both are likely forced into physical similarities due to the fact that they are both 80mm plus porro prism spotters. The objective of the ZEN ED 2 actually measures 85 mm, but is stopped down to the advertised 82 mm effective aperture. The scope is 15 inches long and weighs 64 oz. This is with the eyepiece. It is 13.75 inches, sunshade retracted, and 56.0 oz without.
The objective is a triplet, two pieces are cemented and air spaced from the third element. There is s fourth lens near the tripod mount plate. I do not know which two elements of the triplet are cemented, but I do know that two of the elements are ED.
Both the Kowa and the ZR have a dual range coarse/fine focus arrangement.
Theron MAG 82
This is a little different from the other two scopes. It has a center helical, single rate focus collar just ahead of the tripod plate. It looks a lot like the Nikon 82 ED Fieldscope. It also comes with a 25-75x zoom eyepiece and a 30x wide angle as well. The Theron is on a special introductory offer of $950 with both eyepieces. Like the ZEN ED 2 it comes with a removable soft cover, view-through arrangement. Regular msrp is $1,200. The scope is 13.75 inches long and weighs 62.0 oz. EDIT: Also without eye piece and sunshade retracted. Sunshades on all extend about 2.75 inches.
The objective is the more common triplet with two elements cemented and air spaced from the third.
Comparisons
The removable eye piece assemblies are obviously quite a bit different, the Kowa being about twice the size of the ZEN. Both are bayonet style. The ZEN eyepiece, as noted elsewhere, looks like a dead ringer for the Swarovski, but Zen Ray also told me they did not advise interchanging them. The Theron has a threaded eyepiece that looks like a standard threaded style, so there may be some leeway in selecting different eye pieces.
I don’t think the Kowa interchanges with anything else.
The objective designs of all three of these are designed to focus all three (red, blue, green) primary light waves at the same point with the design intent of elimination color fringing and chromatic aberrations.
I suppose the obvious question foremost in most people’s mind is if the ZR spotter is the optical equivalent of the ZEN ED 2 binoculars. As far as I can see, the answer is yes. Ditto Theron. The ZEN spotter seems built better compared to the Kowa than the ED 2 binoculars compare in build to the alpha brands. The actual quality of the physical construction seems virtually equal to the Kowa. The Theron is also very well built, showing no weaknesses compared to the others, so I don’t think that construction will be a concern with any of the three.
The Theron arrived after I had the others pretty well done. So I had a little knowledge of what it had to stand up against. Also I was more careful to be sure not to smudge anything. The first thing that stands out is that the fov with the standard zoom eye piece is narrower than either the ZR or the Kowa. Other than that it stood up very well for itself. The surprise of the review is how good it is over 60x. The Theron, like the others started showing some image drop off by the time the dial hit 50x, but the Theron carried that image to 75x, and was not overpowered by that much magnification.
I have always thought that performance in any spotter started to decline as the exit pupil dipped to less than 2.0 mm. So it is with these much past 40x, although, what there is, is not much. The fall off in all three is about the same between 40-50x, and the Kowa is a little better than both the ZEN and the Theron from 50-60x. The ZEN with a wider fov is a bit easier to keep centered at higher magnification that the Theron. Up to 40x, there is nothing save the ever so slight edge difference, and the somewhat smaller fov of the Theron, that separates these scopes. The Kowa shows a little better brightness over 50x than the others. And the distortion on the ZEN and Theron increases a bit. When I say a bit that is what I mean. Without a side by side you would never know it.
I wish I had 30x WA eyepieces for the Kowa and ZR. The Theron 30x WA is pretty neat. At least twice the apparent size fov of the 25-75 zoom at 30x, and noticeably larger that the 30x setting on the Kowa and ZR. Nice and flat and quite sharp on the edge. I would probably wind up using this as the main use eye piece and switch to the zoom when I found something that 30x wouldn’t handle. An extra eyepiece would not add much weight. The WA should appeal to digiscopers as well. The objectives of the three scopes are somewhat different from each other. The most significant thing you will note is the diameters of the oculars. Typically the fov increases with increase in ocular diameter. The Theron 25-75 has a total outside diameter of 46.66 mm with an ocular lens diameter of 15.75 mm. The 30x WA on the other hand is 52.75 mm and the lens is 31.55mm, or in other words the 30x WA has over four times the glass surface area in the ocular compared to the 25-75. The ZEN is 56mm with an ocular lens of 25mm. The Kowa is 55.5 and 24 mm respectively, both considerably smaller than the Theron WA. The Kowa and ZEN 30xWA will have wider ocular glass as well, but I don’t know what the sizes are.
Now I have admitted I can find nothing to object to or even wish to improve in the Kowa, so how do the ZEN ED 2 and the Theron MAG 82 really stack up? Well the ZEN ED and the Theron are both serious glass and the stack up very well. The ZEN and Theron have a slight amount (very slight) edge distortion. They do not bend any lines at the edge and the little distortion there is will not force the viewer to automatically center an object on the field edge. But side by side, it is a difference. The ZEN may have an ever so slightly warmer color bias than the Kowa. The Theron is maybe a cooler bias than the ZEN. Not better or worse, just a little different from each other.
You can just about forget chromatic aberrations and color fringing in any of these three instruments. I had ideal conditions for it, and I tried and failed to make it show up. There is a large mountain about 5 miles east of me that soars up in the air over 3,000 feet in about a mile. With the bright afternoon sun on that snow white face and skyline against a bright blue sky that view will show CA if it is going to show at all. So will Bald Eagles (six around the place over the last few days) or our Black Angus cattle against a snow background in the bright sun.
A handy stationary evaluation targets was a bright blue cobalt blue sign with white letters. The sign is on the end tower of the neighbors Valley Irrigation Center Pivot. It says “Valley”, below that “8000 series” and the double Valley Irrigation logo off to the side. The larger letters are 4” tall, the smaller are two inches. The double V logo, one V inside another, is 4” tall, with a one inch wide space between the two V’s. The laser rangefinder called that sign 1,115 yards away.
There are two noticeable operational differences. First, the zoom function of the eyepiece is much easier to operate on the Kowa. Whether or not this was a function of design, the very cold weather stiffening the ZEN more than the Kowa, or maybe the Kowa has been used enough that the movement has eased up, I can’t say for sure, but it was noticeable. There is much less movement on top of the tripod when zooming magnification with the Kowa. The Theron’s screw in eyepiece needs to be pretty firmly screwed in or the eye piece will unscrew when you move the power ring. This is a good indication of how tight the eyepiece needs to be. Focus improves as you go from not quite tight enough to just right. I’d like to see the focus collar on the Theron eye piece a little larger in diameter so it is easier to feel. Second is the relative speed of the focus wheel movement. Both are similar in coarse and fine focus wheels and the Kowa has a faster rate of focus than the ZEN, using about half of the movement of the ZEN. It was actually easier to dial fine focus at high magnification, for me anyway, with the ZEN. The problem with the Theron is after it hits 50x, with the single rate focus. The depth of field decreases with magnification increase and it is a lot easier (for me anyway) to use the fine setting of the dual range to dial in your target in the center of the field depth. That problem eased up quite a bit as I used it more and got accustomed to it, but the dual range is mostly easier. That is until you have to wear gloves. Then the big collar is a lot easier to manipulate. I doubt that 75x will get a lot of use, but the extra 15x is there when you need it. Unlike the Kowa or ZR the offset eyepiece is of set to the right making it easier to sight along the top scope body to line up the scope.
Additionally, all three of these spotters are very good with handling glare and in controlling stray light. The Kowa is a little better in both regards. Looking toward bright light in the ZEN, I could move my head around and induce some glare. It was possible, but not so much with the Kowa. The Kowa has a four stop eye piece and the Zen is a threaded on eye cup so it can be adjusted anywhere you like in the range. The Theron is a three stop adjustment. All three worked well enough both with and with out sunglasses.
So, to close this up, is the Kowa a better instrument? Sure it is. Not much doubt of that. I think serious digiscopers would really like that nearly perfect, flat, edge sharp picture. Are there better spotters than the Kowa? Maybe, but truth be told, I’d have to see it for myself. From my perspective, the ZEN or the Theron will do anything most people need done with a spotter. I would be sort of hard pressed to give an account of the difference, but I suppose if I gave the Kowa a 100 rank, the others would be something like 97-98. The differences, while there, are pretty slight and not many will notice without a side by side by side. I’d be plenty happy to take the ZR or the Theron pretty much anywhere.
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