Preconceptions Bite the Dust!
A Baffling Problem
Almost a best buy
Review and Chart Notes
Living Bird Feather Resolustion Test
90% of the time, the only optical aid even the most serious birder needs is a good pair of binoculars. I recently wrote a spotting scope article for one of the main-stream birding magazines, and, even at the risk of quoting myself, I will give you the most important bit of it here (in a slightly amplified version): "First, before you even consider a spotting scope, spend your money on the best birding binoculars you can afford."
That said, there will undoubtedly come a time when you will want a spotting scope. One or two trips to a National Wildlife Refuge where the birds are always on the back side of the impoundments (generally across a ditch and behind the "Authorized Personnel Only No Public Access" sign) will get you thinking. Then there will be a hawk or two on telephone poles three muddy fields away or a nesting Longeared Owl at the top of a huge cottonwood or a flock of sandpipers on a sandbar or your new feeder over at the far property line. In one or more of those situations someone is going to say, "Here, I've got them (it) in the scope," you are going to look and be lost! Pow! Now that's a view of a bird! Instant scope fever!
A good scope gives you the brightest, clearest, upcloseandpersonal view possible sometimes giving you an even better than birdinthehand view. To see the same amount of detail that one of the scopes in this test provided at 10 yards, I had to use a 4X magnifier at less than an inch! Now, put a bird at the feeder in front of that scope and I think you can imagine the possibilities. Then too, a scope can bring in birds that are literally beyond the range of the naked eye, and make recognizable, enjoyable, feathered bodies out of those little smudges of color in your binoculars.
It is true that you will never justify the cost of a high quality scope if you only consider the amount of time it gets used in comparison to your binoculars but if you consider the enjoyment it brings the range of new possibilities it opens then you will soon realize that a spotting scope is an excellent birding investment! And, of course, there is really only one cure for scope fever you just have to go out and buy one. That's where this issue of Better View Desired comes in.
This first scope test is limited to refractor scopes (those that use only lenses as opposed to those that also use mirrors see page 2). As it turns out, it is also pretty well limited to porroprism scopes (though there are three scopes in the group that use different erecting systems see the individual reports). I was especially interested in reviewing the new apochromatic scopes the ED and fluorite models and the new crop of larger 80mm scopes. The one scope that is conspicuous by its absence is the new Bausch and Lomb Elite 77mm ED. It simply was not yet available for testing. Hopefully you will see a review of it in a future issue (we will also be covering roof prism refractors and catadioptric scopes in the future). I have also included an article on big binoculars as an alternative to a scope 5 pound 20X80 binoculars made primarily for astronomy are a handful in the field but certainly a viable alternative for the semipermanent feeder, nest, or hawk watching installation.
Preconceptions Bite the Dust!
One of the best ways to get a feeling for this test is to examine some of my preconceptions and the ways in which they were overturned.
1. Bigger is better!
Personally, I have always felt that there is no substitute for large, high quality objectives in binoculars. I am willing to carry quite a bit of extra weight and bulk to get the sharp, bright, finely detailed view that only large objectives can provide. Big glasses seldom let you down. The view of birds close in is intimate and always aesthetically satisfying. As the light fails those big lenses just keep gathering and funneling the color and detail to your delighted eyes. When the birds are way out there, big glasses get the id when many a lesser glass would fail. The view is always so easy you never have to strain after detail in shadow or highlight, near or far the birds are just there for you to enjoy. Bigger is better!
I expected, of course, to come to the same conclusion in testing scopes. I was all set to like the 80mm scopes a whole lot more than the little 60s. Stands to reason!
I want to tell you 80mm scopes are big! And heavy! 80mm scopes are big and heavy. Worse yet, they are so big and heavy that they make towers of jello out of all but strongest (and heaviest) tripods. Just finding room for scope and tripod in the back seat of a compact car is a chore. Carrying your scope and support around the end of a lake to that attractive viewing point is a major undertaking.
There is a psychophysical effect in all that mass and bulk too (with maybe an extra bit added for the $ investment). The smaller scopes feel like binoculars. You get pretty confident about tossing them in the back seat; slinging them, and a relatively lightweight tripod, over your shoulder in the field; setting the scope casually down on a rock when you need both hands for the binocs. Not so the big guns. Most of them are built very solidly and would undoubtedly take a good deal of abuse, but I always felt like I was barely in control of all that glass and metal that a moment's inattention might lead to disaster. It's hard to express, and it was worse with some scopes than others. Paradoxically, the scope I liked best among the big scopes was also the heaviest and bulkiest (by a factor of two) perhaps because it felt like that much glass should be encased in that much metal just to make it safe!
As far as performance went, under some extreme field conditions the 80mm scopes do have an edge. If you often need high powers for birds that are just at the limit of conjecture (or just beyond), then, again, there is no substitute for the simple ability of large objectives to resolve fine detail. I was pleasantly surprised, however, at how close the best of the 60mm scopes came to equaling the performance of the average 80mm scope (and remember the average 80mm scope in this test was a $1000 apochromat). Given the fact that the 60mm scopes sold for one quarter to one half less, weighed less than half as much, and were only half as long and bulky, I came to really appreciate the little guys. The best 60mm scopes, in my studied, posttest opinion, would meet 95% of the typical birder's scope needs, and even an average 60mm would be all that was needed 80% or more of the time. So much for bigger is better!
(You might note that the one area in which 80mm scopes consistently outperformed the 60s was in edge field resolution. With the exception of the Nikon Fieldscopes, all of the 60mm scopes were pretty fuzzy out at the edge. All of the 80mm scopes did much better, and a few had excellent resolution right out to the edge of the field.)
2. Multicoating is a must!
(See the Optical Speak section for a refresher on coatings in general.)
In binoculars the difference between fully coated optics and multicoated is immediately obvious and marked enough so that anyone who has ever seriously compared the two would never again settle for fully coated glasses. Multicoated binoculars appear clearer, sharper, brighter, and maintain detail deeper into dusk than fully coated glasses of the same size and power. It is even possible, in extreme lighting conditions (deep dusk, heavy backlight, etc.), to see the difference between plain multicoated (some glass surfaces multicoated but not all) and fully multicoated binoculars (all air to glass surfaces multicoated).
Multicoating is now readily available in binoculars selling for less than $100, and many glasses in the $200-$300 range are fully multicoated. I am convinced that multicoating is the single greatest improvement in binoculars design that we are likely to see in our lifetime, and honestly, I fully expected to see the same kind of performance difference in scopes.
Imagine my surprise then, when I saw how few of the scopes, even the most expensive scopes, featured full multicoating. (I was even more surprised to find that a few that do advertise full multicoating have obvious white reflections, very likely because they have uncoated surfaces in the prisms.) I was amazed to find that a scope of the rumored quality of the Nikon Fieldscope II ED was not, apparently, even fully coated! What a disappointment!
This section is about overthrown preconceptions, so you have probably already guessed that my experience with these scopes in the field demonstrated that, while you can see the difference between some multicoated scopes and others that are fully coated (or "not fully," as the case may be), it is not nearly as dramatic as the difference is in binoculars. Some of the manufacturers that I spoke to on this issue gave good reasons for their choice of coatings. A single coat of magnesium fluorite is still the hardest and most scratch resistant, and offers the greatest protection for the outer surfaces of objectives and eyepieces. One maker said that their tests of fully multicoated and partially multicoated prototypes yielded only a 3% increase in light transmission, at a cost that they just could not justify adding to an already expensive scope. Several mentioned their view that the use of high refractive index materials (ED glass and fluorite, see below) eliminates enough of the reflections already to make multicoating overkill.
In my tests it was indeed apparent that the lack of multicoating degraded the performance of the non-ED scopes more than it did in equivalent ED models. There was a slight, but noticable, difference in image contrast between the non-ED Nikon Fieldscope with partial coatings and the equivilent fully (?) multicoated Kowa TS-612 but there was no apparent difference in contrast between the ED Fieldscope and the ED Kowa TS-614, with apparently the same coatings as their lesser siblings. I am still convinced that full multicoating would improve the performance of all of these scopes. The optics market being what it is, I expect that simple competitive pressure will force more and more of the makers to multicoat their scopes in the near future, and that full multicoating will become the norm within not too may years. All to the good but in the meantime I would not let the lack of multicoating stop me from buying an otherwise excellent scope. Remember, the top 60mm scope in this test (yes, the Nikon Fieldscope ED is as good as rumored) is not, apparently, even fully coated!
3. ED and Fluorite apochromatic scopes are obviously where it's happening!
Again, I expected to see a noticeable, even dramatic, difference between standard achromatic spotting scope objectives and the new apochromatic lenses. (See Optical Speak if you need a short course on the difference.) In theory, apochromats should yield noticeably cleaner, clearer, more intense colors, more contrast overall, and at least slightly better resolution.
After testing these scopes in the field I have to say that, at least with the current crop of ED and fluorite lenses used at low to medium powers (20 30X), the performance improvement provided by apochromats is just barely perceptible and even where a difference is evident, I am far from sure that it can be attributed solely to the use of ED or fluorite elements in the objective. One reason may be that, as is pointed out in Mr. Link's letter (see Reader Response on page...), with the relatively short focal lengths found in most spotting scope objectives, it is very difficult to achieve true apochromatic performance even with the most exotic of materials. Then too, since the materials are so much more expensive than ordinary glass, you would expect more care to be taken in the manufacture of exotic elements. That extra care alone could account for some of the visible improvements in the contrast and resolution of the resulting lenses. In actual field tests, comparing the same scope with and without exotic elements, or in comparing different makes in the same price range, one of which used fluorite and one of which used a standard two element achromat, in both cases at 20X, no one exclaimed over any obvious visible difference, and several birders preferred the achromats. The one scope that did show a visible and obvious performance advantage in the field, one obvious enough so that everyone who looked through it commented, was the Tel Vue Pronto with a 70mm ED objective and yet, high power, bright light tests showed that it had more uncorrected color fringing than either of the 80mm fluorite scopes (not that it had much)! Go figure.
Unfortunately I did not have the foresight to request a high power eyepiece from each manufacturer. Any performance differences between achromats and apochromats should be more evident at higher powers. Still, my experience with this group of scopes, and the few I did have high power eyepieces for, leads me to believe that we are talking about very subtle differences indeed.
On the other hand, if you look carefully at the comparison charts for each class of scopes, you will see that where I was able to compare the same scope with and without apochromatic objective, in each case the apochromat did, for whatever reason, slightly outperform the achromat. In the 60mm class, the Nikon and Kowa ED scopes, especially in field tests, provided a level of performance that was subtly, but noticeably, better than any of the non-ED scopes. At the same time, the Swarovski 80mm achromat easily equaled the performance of the two fluorite scopes in its class in almost every test and field condition. (You would hope it would since it also sells for as much as either of them it will be interesting to see what Swarovski will do with exotic materials!)
Apochromatic scopes are certainly the wave of the future, and certainly most of the best scopes on the market today are apochromats, but the dramatic difference in performance that I expected is simply not yet there.
4. Zoom eyepiece? Never!!!!
I don't like zoom eyepieces. Zooms generally have lower contrast, lower resolution, lower brightness, and narrower fields of view at all powers than equivalent fixed power eyepieces. Some of them aren't actually too bad at low powers, but most are terrible at any other setting, and all but completely useless at high power. Overall, the test confirmed all of my prejudices. However, just to keep things interesting, the Nikon 20-45X zoom for the Fieldscopes is a fine eyepiece that I would not hesitate to mount and use full time and the Swarovski 20-60X zoom is amazing, the only zoom I have ever seen that comes close to equaling the performance, in both brightness and detail, of fixed eyepieces at all powers! Zoom eyepiece? Sometimes...
5. You can always find a bargain!
In every test I have done so far, both for BVD and for articles in the main stream birding press, I have been able to find at least one model that provided outstanding performance at its price point a bargain! Not so scopes! In the first place, there are no really "inexpensive" scopes (at least none that a birder should consider). After testing all these scopes, the brutal fact is, to equal overall quality of the view provided by $200 $300 birding binoculars (the lowest price point at which you are buying "aboutasgoodaviewasyoucanget") you have to spend between $400 and $700 on a scope. Ouch! That is not to say you shouldn't bother with anything less than an expensive scope. When you need a scope, or when scope fever has its hold on you, even a less than optimum view is better than none at all, and there are several scopes in this test in the $200 $300 price range that will provide you with satisfactory performance. I am very uncomfortable though, calling any of them a bargain!
I learned a good deal in testing these scopes. I hope you will learn as much in reading this issue of Better View Desired.
A Class of One
There is one scope in this test that, for several reasons, must be placed in a class of its own.
The Tel Vue Pronto 70mm ED is big, heavy, somewhat awkward to use, and provides, quite simply, the best optical performance of any piece of equipment I have tested so far. At 10 yards, the view is exactly like using a 4X magnifier at less than an inch. In the field, with a 20X eyepiece at anything under 50 yards, you still get more feather detail than you could see with the naked eye, even if you had the bird in your hand. At 64 power I was able to see every plumage marking, every feather of a female merlin at close to a half mile across open water and fields. In direct field comparison, the more difficult the situation long distance, poor light, heavy contrast, whatever the more clearly the Pronto excelled. Every birder that looked through it was simply, and vocally, amazed. Typical comment: "I wish we had this scope here last weekend when we were trying to id that Glossy Ibis!" or, with the addition of the wide field Panoptic eyepiece (see below) "What a scope for breeding bird surveys!" In bench tests, the Pronto scores just slightly above any of the other scopes, but in the field the difference is marked enough so that your immediate impression is: "Oh, so that's what the view through a scope is supposed to look like!"
I doubt that many birders have ever heard of Tel Vue, but if you flip through the pages of almost any magazine that covers amateur astronomy, you can't miss their full page color ads. Tel Vue is one of a small group of optics companies founded within the past generation that have made the US a dominant force in the astronomical market (Celestron and Meade are two others). Almost single-handedly, founder Al Nagler has lead a revolution in high quality eyepiece design, a revolution that has enhanced the view of the heavens for many amateur, and professional, astronomers. "Catch up to Al" has been the name of the game in the eyepiece market for some time now. Although Tel Vue has made astronomical scopes for a few years, the Pronto is their first real attempt at a "cross-over" scope one as useful for bird watching and general nature observation as it is for star-gazing.
You have to understand, the Pronto is not your typical spotting scope. It weighs over 6 pounds, requires an equally massive tripod, and focuses like an astronomical scope two large wheels underneath move the whole eyepiece and erecting system, and a huge chrome tube, several inches back toward the observer. Although Tel Vue offers a rightsideup, rightwayaround, 45° Amichi prism, for the best optical performance you will want the simple right angle mirror diagonal. It is a monster (half of a 3 inch by 3 inch cube with an 8 oz. can of tomato sauce sitting on top), yields an image that is right side up but reversed, and is quite likely to put a serious crick in your neck until you get used to it. On the plus side, most birders found the reversed image surprisingly easy live with and were confidently finding birds within moments of their first look and those cart wheel focusers provide the easiest and most precise focus of any scope I have used.
The Pronto comes standard with a 21mm, 21 power, Tel Vue Plössl eyepiece, certainly a fine performer, with a good field of view and adequate eye relief for the bespectacled. The eyepiece holder will accept specialized 2 inch barrel astronomical eyepieces, and comes with an adapter for the more common 1.25 inch barrels. Tel Vue also sent their new 22mm Panoptic wide field eyepiece for testing with the scope. To put it mildly, the Panoptic is the best wide field eyepiece I have ever seen. For panning flocks of birds, or set up on a nest or feeding station, or finding birds in flight, there is nothing on the market quite like it. (Its dual barrel fits both the 2 inch eyepiece holder and the 1.25 adapter, but you will get closer focusing with it in the adapter.) Before you run out to buy one, though, you should know that the thing weighs almost a pound, is three inches tall, and will set you back something over $250. Sigh!
Tel Vue also supplied a 12mm Nagler type II eyepiece and a 7mm Nagler for higher powers ($200-$300 each). Both are fine eyepieces, but I found that even my inexpensive Edmond RKEs worked well with the Pronto, giving me excellent high power views. I am sure the higher power Tel Vue Plössls would do just fine for those who are interested in maintaining the same quality level as the 21mm that comes with the scope, without investing $600 in eyepieces.
You will have guessed, if you read the lead article, that I didn't really mind the weight and bulk of the Pronto. It feels quite solid, and quite safe, in the field. I am not sure I would want to carry it far, but then I wouldn't want to carry any of 77-80mm scopes far either.
If you are trying to justify the cost of a scope by doing the "multi purpose" thing, the Pronto will also give good service as an astronomical scope, and, with the appropriate adapter, should perform quite well as a 450mm, F6.4 telephoto lens for your camera.
Finally, the Pronto is available through many mail order birding optics dealers for somewhat less than your average 77-80mm fluorite or ED scope.
Bottom line: don't compare the Pronto to any other 80mm or smaller scope unless you are prepared to live with its weight and awkwardness. If the optimum view is your main interest, you may never be satisfied with a "standard" spotting scope again!
It's All True
Nikon is fond of pointing out just how well the Fieldscope ED has done in most tests of birding optics, so I, of course, being the contrary person I am, was determined that if I gave it a good rating it would have to earn it. It did. This is one fine scope. It is very compact (though somewhat heavier than some of the 60mm scopes) and yet it provides optical performance that is enough to make me, at least, seriously question whether I would buy and carry any of the bigger scopes. When you add the fact that it has one of only two really usable zoom eyepieces on the market, you have a package that is hard to beat. In addition to having exceptional center field resolution, it is the only scope in the 60mm class that held its sharpness right out to the edge of the field. The helical focusing collar on the barrel (like a telephoto camera lens) is handy and precise, but takes a bit of getting used to. I had the new 45° viewing model with rotating tripod socket. The straight through model would very likely yield even slightly better brightness and resolution, but there is no denying that the 45° is more comfortable to use in most situations.
I, personally, would like to see this scope with full multicoatings. It would also be nice if Nikon added a slide out lens shade, but despite any quibbles, this is still the scope to beat in the 60mm class, and overall, the standard spotting scope I would be most likely to buy from any class!
In the 77-80mm class there are three outstanding scopes scopes with a mix of performance and features that makes it very difficult to single out one as better than the others. All three provide optical performance that is as good as you are likely to see with prism erecting systems. Among my particular samples, the Kowa TSN-4 77mm Prominar Fluorite scope provided the brightest and most contrasty view by just a very slight margin, but it lacks the waterproofing that both of the others provide. The Optolyth 80mm HD Fluorite is fully rubber armored and sealed against dust and water (even with the eyepiece off). The Swarovski is not an ED or Fluorite scope, but in field use I was seldom, if ever, able to see any difference in performance, and, in limited use, several birders preferred it's more "neutral" view to that of either fluorite scope (fluorite, apparently, shifts the color balance of the view just enough to take some getting used to.) Swarovski makes the only zoom in this class that I would consider using as my primary eyepiece, a very fine 20-60X model that has good eye relief and field of view at all powers, and exceptional brightness. The Swarovski scope is also "immersion tested" waterproof. I found the Swarovski's "gun-metal gray" finish to be the most attractive of the three, but it does collect marks more easily. Overall, I preferred the knobontheprismhousing focus of the Kowa and the Optolyth to the Swarovski's helical collar.
Given the fact that the three scopes are all in the same price range and offer very similar performance, I will have to leave it to you to examine each one to see if its particular set of features and price meet your needs.
There are several other scopes in the 60mm class that deserve a close look. The brand new (due out in April) Kowa TS-614 Prominar ED comes very close to equaling the Nikon Fieldscope ED's performance. It, and its non-ED sibling the TS-612, have about the most complete coatings of any scopes in this group. It is also an attractive scope, with a rubber armored prism housing and slideout lens shade, very precise focusing knob, and a very light weight. Center field resolution, brightness, and contrast are exceptional, but, at least with the eyepieces supplied for the test, its edge of field resolution left something to be desired. Depending on the actual "street price" of the scope when it becomes readily available, this might well be my second choice among all the prismatic scopes tested (and if it comes in at significantly less than the Nikon ED model, it might get promoted to first!).
On a similar note, both the Kowa TS and Nikon Fieldscope non-ED models are very good values, offering identical handling features, and optical performance that, while it does not equal the EDs, is still quite satisfying in the field.
The Nikon Spotting Scope and the Celestron S60 are worth a look if you need something more rugged for heavy field use. Both are well armored and multicoated. The S60 has a very handy builtin low power "finder scope" with crosshairs for lining up your bird quickly. Both offer optical performance that is just off the mark of the ED scopes. The S60 eyepiece could be better. While it is quite sharp and offers good contrast, it has no rubber eyeguard and insufficient eye relief. Still, both the Celestron and Nikon represent good buys.
In fact, the only better buy in the group is the Swift Panther. This little scope is very compact and easy to use in the field, with exceptionally quick focusing. It offers surprisingly good optical performance at its price point, performance which, again, might even be improved with a better eyepiece one with longer eye relief, a fold down eyeguard, and less edge distortion.
Both the Celestron and Swift take standard screwin and screwon eyepieces, and it would be worth shopping around for something better than what comes with them. Orion Telescope Center offers a line of eyepieces that will fit, and most of the eyepieces that come with any 60mm scope will work.
A Baffling Problem
In larger scopes, the Celestron SS80 is interesting, especially if you are going to use it for astronomy and/or photography as well as bird watching. It has a very sharp objective, with excellent center field resolution, and takes standard astronomical eyepieces. The 18mm Orthoscopic that comes with it is a fine performer, and even better eyepieces are readily available. It is incredibly compact for an 80mm scope, weighs a fraction of what the other scopes in its class weigh, and it is available for less than half the price of the Kowa, Optolyth, and Swarovski. Unfortunately, it suffers from low image contrast, apparently caused by a good deal of light bouncing around inside the scope. The inside of the long focus tube, in particular, is quite reflective. I was sorely tempted to take the thing apart and line all the inside surfaces with flocked black paper, slip a ring of black felt around the focus tube to block the light that enters there, or at least spray the inside of the focus tube with flat black paint. In technical terms we would say that the SS80 lacks sufficient "baffling" to block stray light from reaching the eyepiece. I have a feeling that minor changes in design would make this one very fine scope indeed (all you tinkerers out there take notice). Even as is, it would likely offer better photographic performance than any of the scopes that put prisms permanently in the light path, and it is the only scope other than the Pronto that I would recommend for astronomical work. Even with its shortcomings it still rates a "pretty good buy" if you are looking at 80mm scopes.
Serious Quibble/Possible Best Buy ED
Why would anyone make a scope with an ED Prime objective, designed to sell for something over $300, and then saddle it with the same less thanoptimum eyepiece that comes on the little $200 Swift Panther? The Bushnell Spacemaster ED has a lot going for it: handy focus, nice "peep sight" finder, solid body, ED objective but its performance is seriously compromised by the 22X wide angle eyepiece that is often supplied with the standard "birding" package. Put a high quality eyepiece on this scope and you might indeed have an exceptional buy in an ED scope.
Review and Chart Notes:
All scopes were tested with the eyepiece listed in the General Features chart. If other eyepieces were tested, info is in the individual reviews. Resolution was measured at 10 yards at 20-25X. 70-80mm resoluton ratings do not correspond exactly to 50-60mm ratings. Superior for 50 60mm is approximately equal to Excellent+ for 70-80mm models. Brightness is a comparitive figure, with the brightest scope in the test rating a 10.
Tel Vue Pronto
Construction: massive rotating tripod mount, interchangeable 90° mirror diagonal (right side up but reversed image amichi 45° correct viewing diagonal available), dual focus knobs underneath the back of the scope physically lengthen the tube, multicoated optics (not fully multicoated), takes standard 1.25 inch eyepieces as well as 2 inch, ED glass used in objective, photo adapter available. Tube finished in black and pale green enamel.
Field Notes: Massive! Heavy, big, awkward to use because of the 90° view...but, if you demand the highest level of optical performance, this is the scope for you! Unbelievable detail. The view at 10 yards (with a 20X eyepiece) is equivalent to using a 4X magnifier at about 2 inches. You can see more detail from 30 feet than you can with your unaided eye at its closest focusing distance! This is the only scope in the test with edge of field resolution approaching its center field performance. Adding an eyepiece like the 22mm Panoptic ($300<>) gives you the best wide field view I have ever seen. Very impressive. Optically, clearly the best in the class...only you can decide if the view makes carrying all that weight and bulk worth it.
Available direct from Orion Telescope Center, 2450 17 Ave., Santa Cruz, CA 95061-1158, tel. 800-447-1001
Construction: uses "first surface" mirrors instead of prisms to "right" the image, giving a 45° view. Fully coated optics, and mirror diagonal yield less contrast and brightness than other scopes in the class. Sliding tripod mount makes balancing the scope easy, but adds bulk and "ugly" to an already bulky and ugly scope. Interchangeable bayonet eyepieces. Tube finished in textured green enamel.
Field Notes: This is one odd looking scope! It provides acceptable optical performance (with very good center field resolution indeed), but, because of its particularly "dim" view (likely a result of the multiple mirrors and lack of multicoating) several of the 60mm scopes do as well or better over-all. It is also quite heavy.
Construction: multicoated, accepts standard 1.25 inch eyepieces and accessories, two focus knobs under the rear of the main tube extend the eyepiece tube as in an astronomical scope. Smooth black enamel finish.
Field Notes: This should be a better scope than it is. It appears that lack of "baffling" allows light to bounce around inside, seriously degrading the contrast of the image. Better than excellent center field resolution, very light weight, and relatively low street price make it worth looking at if you are in the market for an 80mm scope. If you are interested in a dual purpose scope, the SS80 is the only other scope besides the much more expensive Pronto that I would recommend for astronomical use. Readily available 1.25 inch eyepieces make upgrading the eyepiece for a wider field an option.
Kowa TSN-4 Prominar
Construction: multicoated, slide-out lens shade, fluorite element used in objective, focus knob on top front of prism housing. Interchangeable bayonet eyepieces. Finished in textured green with black accents.
Field Notes: For several years, this has been the birding scope to beat. It now has stiff competition in the same price range from Optolyth, Swarovski, and Bausch and Lomb, but remains an excellent scope in the field. It is somewhat lighter in weight than either the Optolyth or Swarovski, but lacks the full waterproofing that both those scopes offer (the Kowa is sealed with "o" rings, which gives it better protection than most other scopes.)
Construction: identical to the TSN-4 except for its standard achromatic objective.
Field Notes: The handling, of course, is the same as the TSN-4, though its optical performance, as you would expect, is not quite up to the -4's standard. The TSN-2 still represents a good value for those who want 80mm performance on a somewhat less exalted budget.
Optolyth TBG 80HD
Construction: rubber armored (deep green), water proof (even with eyepiece off), rotating tripod mount, fully multicoated eyepiece, multicoated objective, slide-out lens shade, large focus knob on the front top of the prism housing. Interchangeable screw-in eyepieces.
Field Notes: A very fine scope that "feels right" in the field. Optical performance provided by the fluorite element objective is excellent, but, at least in the sample in hand, not exceptional in this class. Among the best fields of view, especially with eyeglasses. Higher power (30 and 70X), wide field eyepieces are available (the 70X is new and unique).
Construction: "immersion tested" waterproof (even with eyepiece off), fully multicoated, focus ring on barrel of scope, straight through model now available. Interchangeable bayonet eyepieces. Finished in "gun-metal gray" textured enamel with black rubberized focus ring and accents. Porroprisms slung under the body of the scope for a long and low look compared to other 80mm scopes.
Field Notes: Excellent 80mm performance, practically indistinguishable from the scopes in this class that use "exotic elements." The 45° viewing model was exceptionally comfortable to use in the field, and the view compared very favorably in all respects to the straight through model. I would seriously consider buying the AT80 with the Swarovski zoom as my only eyepiece, and that's saying quite a bit for the quality of the zoom. For whatever reason, in direct comparison many birders preferred the view through the AT80 to that of the fluorite scopes in the same class. I also tested the 22X eyepiece. It has substantially wider field, but the zoom at low power equals its resolution.
Aus Jena 60/375
Construction: white, heavily pebbled texture is quite attractive, narrow tripod mount, fully multicoated, focus by screwing eyepiece in and out
Field Notes: Awkward focus placement is this scopes major shortcoming. Optically quite good with excellent contrast. Very solidly made.
Bushnell Spacemaster EDPrime
Construction: hard textured very dark gray (almost black) metal finish, built in "peep sight" on top of prism housing, large focus knob recessed in right side of prism housing. No multicoating. Apparently there are uncoated optical surfaces. Interchangeable screw-in eyepieces
Field Notes: This scope is proof that ED glass does not necessarily make an excellent scope. Field performance is very good, with typically excellent contrast, but several of the non-ED scopes equal or better its overall performance. The built in peep sight is nice, and the recessed focus on the side of the prism housing is excellent...there is no protruding knob to snag and it is very easy to use in the field. The limiting factor here is undoubtedly the eyepiece. It is exactly the same eyepiece that is supplied with the much less expensive Swift Panther. Lack of fold-down eyecup limits the view with eyeglasses. You could invest in a better eyepiece, but really, you would expect B&L to supply one on an ED Prime scope. Multicoating would very likely improve the performance of the scope. The price is attractive, and since the body is readily available without eyepiece, it makes shopping for a better eyepiece a real possibility.
Construction: heavy black ribbed rubber armor, multicoated, screw-in interchangeable eyepieces, built in low power "finder scope" with crosshairs
Field Notes: The S60 provides excellent center field resolution and contrast, and the rubber armor makes it a good choice where the going might get rough. The lack of rubber eyeguard and sufficient eye relief make it less than ideal for eyeglass wearers. The "finder scope" is excellent, and puts you right on the bird every time.
Construction: very small and compact, black enamel finish, focus by screwing the fixed eyepiece in and out
Field Notes: I often dismiss 50mm scopes outright. Most do not offer enough better a view than binoculars to make them worth carrying. This little scope, however, would slip into a pocket and might make a few long distance id's possible on those days when you don't want to carry a fullsized scope. Overall, quite good optical performance.
Kowa TS-614 Prominar
Construction: lightweight body with rubberized prism housing and slide out lens shade (green with black accents), sighting ledge on side of prism housing, bayonet eyepiece attachment, focus knob at upper right front of prism housing, fully? multicoated
Field Notes: This scope has the kind of view you would expect from an ED objective. Superior center field resolution and exceptional contrast and color clarity. Edge field resolution might be improved by substituting a normal field eyepiece for the wide angle. While I doubt that the scope is "fully multicoated" (there are at least two purple reflections which generally indicate surfaces with regular magnesium fluorite coating), it certainly has the most complete coating of any scope in the 60mm class. Even the prisms appear to have been coated! The light weight and nicely finished body with very precise focus make the scope very comfortable in the field. The zoom eyepiece is a disappointment. Invest in two or more fixed eyepieces. A close second to the Nikon Fieldscope ED.
Construction: except for standard achromatic objective, identical to TS 614, see that review
Field Notes: Physically this is the same scope as the TS-614. It has all of the handling advantages of that scope, but lacks the superior optical performance of the ED objective. I suspect that the difference, at least at powers in the 20X range, is due more to the precision of workmanship lavished on the ED glass than it is to any inherent advantages the ED objective has. If handling and price considerations are more important than eking out the absolute last dot of detail, this scope is worth a look.
Nikon Spotting Scope
Construction: heavy graygreen rubber armor with an attached cap for the objective, screw on eyepieces, sighting slot on top of prism housing, long focus knob protrudes from front of prism housing, multicoated (though not "fully multicoated")
Field Notes: Heavier than most of the 60mm scopes, but the rubber armor makes it less likely to get dinged up in the field. Both contrast and center field resolution are outstanding in this group, despite the lack of any fancy glass in the objective. Excellent eye relief and close focus. Scope handles well in the field and gives very nice views.
Nikon Fieldscope II ED:
Construction: green textured metal finish with rubber coated prism housing, screw on eyepieces, protruding tripod mount, textured rubber focus ring on barrel of scope, fully coated (?). ED glass used in objective. Both straight through and 45° versions available. (45° model has rotating tripod socket.)
Field Notes: Well designed, fairly compact, with exceptional optical performance. This is the only scope in the 60mm class with decent edge of field resolution. Multicoating might improve the contrast. The very high brightness figure may be a result of the particular color balance of the image, it is slightly "warmer" (slanted toward the yellow end of the rainbow) than most of the other scopes. As zooms go, the Nikon zoom is exceptional. This scope could easily make you wonder why anyone would carry an 80mm monster. Best in Class!
Nikon Fieldscope II
Construction: the non-ED Fieldscope, otherwise identical to above.
Field Notes: Also an excellent performer. Optically just off the mark of the ED model, but still a very fine view of the bird. Worth considering if you can't swing the ED model.
Construction: apparently this scope has some uncoated optical surfaces, very compact body with gray "rubberized" texture, large focus knob on the right side of prism housing, screw in interchangeable eyepieces
Field Notes: Given its very compact size, moderate price, and reasonable optical performance, this scope is a good buy. The large focus knob is among the easiest to use in the field. Multicoating and a better eyepiece would improve the performance greatly. You can't do anything about the coating, but better eyepieces are available. The heavy rubber eyecup on the eyepiece is comfortable for non-eyeglass wearers but it does not fold down, limiting the field for eyeglass wearers. Still, if you are on a limited budget, this scope is worth looking at.
Living Bird Feather Resolution Test
If you have never looked at a bird at the feeder through a good scope, it is hard to imagine just how much detail 20-30 power provides at anything under 60 feet.
Feather, our young cockatiel test bird, put in a long morning posing for this set of scopes. The only surprise was that there really were no surprises. In testing binoculars, I have found that there is not always an absolute correlation between the results of the "objective" tests resolution, contrast, and brightness and the more subjective feather resolution test. The resulting rankings are almost never exactly the same. It is not unusual for glasses ranked 5th or so on the sterile resolution charts to come out on top when the subject is a real live bird. I've often pondered reasons, but I have no definite answers.
This scope test did not provide me with any either. Scope for scope, the ones that rated best on the bench also rated best in the feather resolution test. In fact, they all did so well that I ended up having to group them.
Group One: Superior
Tel Vue Pronto
Group Two: Not quite superior, but better than excellent.
Kowa TSN-4, Kowa TS-614, Nikon Fieldscope II ED, Nikon Spotting Scope, Swarovski AT80
Group Three: Excellent
Aus Jena, Bushnell Spacemaster ED, Celestron S60, Celestron SS80, Kowa TSN-2, Kowa TS-612, Nikon Fieldscope II, Optolyth TBG 80HD, Swift Panther
Group Four: Just off excellent
AlderScope 80, Celestron S50
The only surprise, as noted elsewhere, is the 60mm scopes up there in the "not quite superior" group. Gives you pause, doesn't it?
Over the past months I have had several phone conversations with Henry Link, a birder, amateur astronomer, and optics enthusiast from North Carolina. I persuaded him to put some of his thoughts on spotting scopes down on paper so that I could share them with you. The following are excerpts from a longer letter.
"It seams to me the main problem in designing a no compromise telescope for birding is how to make the scope small enough to be carried around but with enough brightness and resolution to produce a useful 100X. I've found often enough that a good 90X-100X can make distant birds indentifiable that are not quite there at 70-80X and are just little blobs at 20-40X. I also enjoy the sheer beauty of image such a scope has at lower magnifications. Apochromatic refractor objectives in the 75-80mm range can theoretically produce this kind of optical quality but the manufacturers of birding scopes of this size have chosen, in order to make them small enough for field use, to allow optical compromises (very short focal length, complex erecting prisms) which in most cases so severely degrade the performance that what results is more like the performance of a theoretically perfect 45-50mm scope in regard to resolution with the brightness of a perfect 60 to 65mm scope. It makes no sense to me to make a 75-80mm scope so short that it winds up performing like a smaller scope. The design goal should be to make the scope as small as possible while maintaining uncompromised performance.
Scopes substantially optically superior to the current generation of birding scopes can be produced either by increasing the focal length from the now almost universal 420mm to something in the range of 500 600mm or by employing a triplet objective design (along with fluorite, ED, or SD glass) in the 400-500mm range. In addition the focusing and image erecting system can be designed to allow user choice. If the best image quality is desired a diagonal prism or mirror can be used instead of the usual porro or roof prism.
Perhaps the first step in birding scopes getting better is for birders to become better educated about what a theoretically perfect image looks like. At the moment I think if you want to see such an image you have to turn to small apochromatic refractors designed primarily for astronomy. Of the scopes available in the U.S., the Takahashi fluorite refractors are so far the best I have seen. They are available in 50mm (better resolution than a Kowa 77mm fluorite!), 60mm and 76mm. There is both a doublet 76mm (model FC-76, 600mm focal length, the scope I use) and a triplet (model FCT-76, 487mm focal length). The 60mm is available in a spotting scope version called the "T-Gull" which is lighter and has a combination draw tube and helical focuser in place of the rack and pinion."
From Henry's personal list of gripes about current spotting scopes:
"1. Focal ratios too short for the optical design."
Henry maintains that, for high power performance, even fluorite objectives need a focal ratio (focal length divided by the objective diameter, the same figure used to measure how "fast" a photographic lens is) of F8, and ED objectives need F10. Triplets might go to F5-6 for fluorite and F7-8 for ED. Most current 70-80mm scopes, achromatic or apochromatic, have focal ratios in the F5-6 range. 60mm scopes tend to be somewhat longer at about F7.
"2. Complex prism erecting systems."
See the discussion under The Correct View on page 10. Mr. Link is even more emphatic in his opinion of how much porro, roof, and 45° prisms degrade the image.
"3. Poor internal baffling."
See the comments on the Celestron SS80 for more on baffling. In essence, too many shiny surfaces inside a scope allow "stray" light to reach the eyepiece and degrade both the resolution and contrast of the image. Some companies even build little "light traps" (baffles) inside their scopes to eliminate the last of the internal reflections, and you can see the difference in the image.
"4. Partial or no multi-coating."
"If Nikon can multicoat the 24 air to glass surfaces in a $300 E type binoculars, why can't they multicoat the 10 surfaces in an RC scope, not to mention the ED Fieldscope?"
Good question! For another slant on this, see the discussion of multicoating in the Scope Fever article and the Optical Speak box.
"5. Fluorite and ED glass."
Mr. Link objects to fluorite's fragile nature (there are reports of fluorite objectives cracking under extreme temperature changes) and uncoatablitly, and to ED's failure to provide true apochromatic performance in most objectives.
"There is a new glass type called SD being used by Pentax and others in astronomical refractors in Japan (and Astro Physics in the U.S.) which is supposed to have the optical characteristics of fluorite without the drawbacks."
My own summary of Mr. Link's thoughts goes like this: better spotting scope performance is possible and birders will only get better performance if we know what we want and let the manufacturers know that we want it.
Unless you happen to be interested in amateur astronomy, you may not know that binoculars don't stop at 50mm objectives. Astronomers regularly use 70-100mm binoculars for wide field views of the Milky Way, studies of the nebulous clouds of gas and large faint galaxies in the heavens, and searches for the latest comets (Swift-Tuttle, last year's major comet news, was first located with a pair of 154mm binoculars). Astronomers use binoculars because they know that we see several times the amount of detail with both eyes as we can see with one. Our brains are wired for two eyes. It is the view we are used to. It is only natural then, when we begin to think about large spotting scopes 70-80mm to wonder how a pair of monster binocs would do instead.
The most common astronomical binoculars, the 80mm size, come in several powers, from 10 to 25. I requested several 20X80 models. I received the Celestron and Orion 20X80s, both fully multicoated models with BAK-4 prisms, and both, if I am not deceived by appearances, made by the same supplier in Japan. I also received the Swift Observers, 20X80 glasses with lesser full coatings and BAK-7 prisms (and, apparently, the exact same body as the other two). The Swift glasses sell for around $300 and the others for nearer to $400, but that still makes them very competitive with spotting scopes. All three are supplied with a tripod mount built in and an accessory tripod adapter to attach them to standard photographic tripods.
There is no doubt that using binoculars is easier on the eyes and brain than using a spotting scope. Every time I went to the binocs after using the scopes, my mind went "ah, that's better!" On the down side, none of the binoculars equaled the resolution or the apparent brightness of the best of the competitive 70-80mm scopes, and you have the added complexity of adjusting the binoculars for individual eye spacing and differences in eye focus when you change observers. You can not slip in a high power eyepiece or twist the zoom as you can with most scopes to reach those far birds.
These are large binoculars. They weigh approximately 5 pounds and stand a foot tall and 10 inches wide. They come with carrying straps but it would take a better man than I to lug them through the forest around the neck, or even over the shoulder. They come into their own on a tripod, and are really at their best in a semi-permanent installation a feeder watching station, an observation deck, a hawk watch tower, a long term nest study, etc.
After trying them in the field, I came to the conclusion that, in most situations, monster binoculars are not a ideal substitute for a spotting scope. I would rather carry a really good 60mm scope with several eyepieces (or one exceptional zoom). At the same time, I would love to have a pair set up in the living room overlooking the feeders on the lawn. I wouldn't mind taking them along when I went to a National Wildlife Refuge or the seashore and expected to spend some time in a blind or on an observation platform sorting ducks or shore birds. And, I certainly would have them out every dark night, drinking the Milky Way and hunting up galaxies and comets!
Bottom line: Monster binocs are not a substitute for a good spotting scope, but they are a valuable tool in their own right. The priorities, for the average birder, might go like this: 1. the best birding binoculars you can afford, 2. a good 60-80mm spotting scope, and 3. (if you haven't exhausted your budget) monster binoculars to fill in the gaps.
|Make/ Model||Objective||Optical Design||Eyepiece||Wt. (oz)||Len. (in)||ListP||Av.P||Overall Rating|
|Tel Vue Pronto||70mm ED||9 0°mir ror||21mm Plössl intch.||97||17.75||800||600||excell ent+++|
|AlderS cope 80||80mm Ach||4 5°mir ror||25X w.a. intch.||75||17.75||780||490||good|
|Celest ron SS80||80mm Ach||Amich i 45°||20X Ortho intch.||41||16||650||350||very good $$|
|Kowa TSN-4||77mm Fluorite||porro s t.thro ugh||20X w.a. intch.||46.5||16.75||1400||900||excellent+|
|Kowa TSN-2||77mm Ach||porro s t.thro ugh||20X w.a. intch.||51||16.25||700||400||excellent-|
|Optoly th TBG80 HD||80mm Fluorite||porro s t.thro ugh||20X w.a. intch.||52||16.25||1500||1000||excellent|
|Swaro vski AT80||80mm Ach||porro 45°||20 60X intch.||64.5||17.5||1200||1000||excellent+|
|Aus Jena 60 /375||60mm Ach||porro s t.thro ugh||23X fixed||35||14.25||1250||???||very good+|
|Bushn ell Space master ED||60mm ED||porro s t.thro ugh||22X w.a. intch.||37.5||12.25||740||400||very good+|
|Celest ron S60||60mm Ach||porro s t.thro ugh||25X intch.||36||15||420||270||very good|
|Celest ron S50||50mm Ach||porro s t.thro ugh||25X fixed||19.5||9.5||200||130||very good|
|Kowa TS 614*||60mm ED||porro s t.thro ugh||20X w.a. intch.||28.5||14.25||605||???||excellent++|
|Kowa TS 612*||60mm Ach||porro s t.thro ugh||20X w.a. intch.||28.5||14.25||1000||???||excellent--|
|Nikon Spotting Scope||60mm Ach||porro s t.thro ugh||20X intch.||43.5||11.75||380||300||excellent-|
|Nikon Fields cope II ED||60mm ED||porro 45°||20to4 5X zoom||45||12.5||1250||750||superior BIC|
|Nikon Fields cope II||60mm Ach||porro s t.thro ugh||20to4 5X zoom||34||12.75||800||500||excellent|
|Swift Panther||60mm Ach||porro s t.thro ugh||22X w.a. intch.||29||12||300||200||very good++ $$$|
|Make /Mod el||FofV (ft /10y ds)||EGFo fV||ER (mm)||Cl.Fo c.(ft)||Res Cnt.||Res Edg.||Res Twi.||Cont||Bri||Rating|
|Tel Vue Pron to||1.25||same||14||16||sup||sup||ex||ex||9.4||sup BIC|
|Alde rsco pe 80||1.46||same||20||34||ex+||g||f||vg||5.6||vg-|
|Cele stro n SS80||1.1||same||12||13||sup-||g||vg||p||7.75||vg|
|Kow a TSN 4||1.83||same||14||20.5||sup-||ex-||ex-||ex+||10||ex+|
|Kow a TSN 2||1.83||same||14||20||ex||ex-||vg+||vg||8.7||ex-|
|Opto lyth TBG 80||1.66||same||14||30||ex||ex-||ex-||ex||9.2||ex|
|Swar ovsk i AT8 0||1to.5||same||20||20.5||sup-||ex||ex||ex||9.6||ex+|
|Bush nell Spm aster||1.75||1||7||22||ex-||f||vg-||ex||7.3||vg++|
|Cele stro n S60||1.17||.75||7||30||ex+||f||vg+||ex||6.4||vg-|
|Cele stro n S50||1||same||10||36||vg+||vg+||vg+||vg+||6||vg+|
|Kow a TS 614||1.75||1.42||12||24||sup||g||vg||ex+||7.5||ex|
|Kow a TS 612||1.75||1.42||12||20||ex-||f||vg-||ex||7.3||vg++|
|Niko n SpSc ope||1.42||same||14||11.7 5||sup||f||ex-||ex||7.9||ex-|
|Niko n FSco pe ED||1.13 to.6||same||15||17||sup||ex||ex+||ex||8.2||ex++|
|Niko n FSco pe||"||"||"||"||ex+||ex||ex||vg+||8.2||ex|
|Swif t Panther||1.75||1||7||26||ex-||f-||vg+||vg||7.4||vg|