OK, bear with me. This is a three scope comparison and it is a bit on the long side.
For a few days now I have had the new Zen Ray ZEN ED 2 angled 20-60x spotting scope. The first thing I decided I had to do was get another spotter to serve as a frame of reference. After some checking around, I located a friend with a Kowa Prominar 884 TSN 20-60 straight and he loaned it to me for this. The Kowa is very lightly used and looks like new. Just about the same time I was contacted via PM about doing a review for the new Theron brand from a company called Predator Optics. So since I had two scopes already I was not about to turn down a chance to look at some more optics. FWIW, Theron is ancient word Greek for hunter.
The weather here has been mostly cold and gray. The lows have been in the -5* to +5* F range and it has not been getting above freezing at all. So the days have been from dull gray all day twilight sort of days to blinding white, hurt your eyes bright, always with a bite clear through you wind. A couple of days have been dense fog with less than ¼ mi visibility, so that has slowed things down somewhat.
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.
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.
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.
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. 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.
I got the ZEN a day before I did the Kowa and initially it was driving me nuts. There was a smudge dead center in the fov and I was not happy with what I saw. Try as I might I could not see where it was. Then, I got the Kowa and I thought, “…well… so much for this comparison”. But I finally figured out where the smudge was on the ZR. Got that cleaned up properly and my disappointment went away pretty quickly. I think it was all my doing as the smudge was on the first surface of the prism assembly under the eyepiece. I never did see anything, but after cleaning that surface, the problem was gone. I must have smudged the surface when I either connected or disconnected the eye piece when taking pictures. That smudge was not there the first time I looked at the ZR It was as the second time I used it, it was plain as day and I doubt I would have missed the same thing initially.
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 “6000 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.
Tripod mounts should be given careful consideration. This is self-evident to anybody who uses a spotter much, but can be easily overlooked for use by a less experienced user. I have a compact Bushnell Legend Ultra ED 12-36x50mm spotter and I just used a cheap tripod I had for occasional use for various things, primarily to hold the chronograph, but it is NOT for serious scope use. It works well enough with the little Bushnell, but boy is it out of its league with a big, heavy, higher magnification scope like the Prominar, Theron, or ZEN. I wound up applying a “farmer’s fix” to the tripod dilemma. I went to the scrap metal rack and found a 3” wide by ¼” thick piece of steel strap about three feet long. I went into the shop and grabbed a heavy C-clamp and clamped the strap to the top board of the bull corral. This is a 16’ long 3”x12” secured to three 8” square railroad ties with 6 inch spikes. I used a window mount adapter clamped the top of the strap, adjusted it to the proper height and clamped it tight. There are three runs of these heavy planks in that fence and this was the single most solid mount I could dream up quickly. But hey, it worked. There was plenty I could see from that point, so that was not a problem. The thing to keep in mind is that I think anyone is far better of by spending less money for a still really very good scope like the ZEN or Theron and using some of the money saved for a really good, solid tripod. More so than putting all their cash into a top scope and wasting the advantage on a tripod they were forced to skimp on. The surprise of this whole deal for me was how much better the little Bushnell was atop the clamped down strap than it was on top of my silly excuse for a tripod. One other tripod note, the prism assembly on the Theron is offset, so the eyepiece sits to the right of the center line. Unlike the Kowa or ZR, it is easier to sight along the 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. 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 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. Mid priced optics just keep getting better.
