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Old Saturday 11th June 2011, 13:45   #1
henry link
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Review of Zen-Ray ED2 82mm Scope

Whew!...this review has been a long time coming. I received the first test specimen of the Zen-Ray ED2 scope way back in late December and a replacement for it in early January. I considered both of those to be too defective (or damaged) for a fair review. A unit from a new production run arrived in May. This one turned out to be good enough for me to feel confident that its optical quality is limited by the design rather than defects or shipping damage, so here, finally, are some test results. As usual, I’ll be concentrating entirely on the optics. I decided to treat the scope body and the eyepieces in separate parts, starting with the body.

Part One – Scope Body

From the outside the Zen scope closely resembles the Kowa 883, but that resemblance is only skin deep. Inside, the objective design, focusing system and erecting prisms are quite different from what‘s inside the Kowa. Instead of the Schmidt prism used in the Kowa the Zen uses a Porro, followed by semi-pentaprism to angle the light path. This erecting system has three separate prisms with more glass to air surfaces and more internal reflections than a Schmidt. It includes one reflection in the semi-pentaprism that has to be mirror coated. To my knowledge Zen is the first to use a dielectric coating for this surface.

Focusing is accomplished by moving one part of the Porro prism, so there is no moving focusing element as in the current alpha scopes. I think this design is a pretty good choice for a moderately priced scope. It avoids one potential optical defect by not having a roof prism split the light cone and in this case the dielectric coating keeps the light loss reasonable. This same system was used in many older high-end scopes, like the Swarovski AT-80 and Kowa 823. I haven’t seen every scope that uses it, but the two scopes I have tested (the Pentax 80ED and the Zen) both suffer some aperture loss as a result of the focusing prism moving out of its optimum position at close focus. I expect other scopes of this design have the same problem. The Zen begins to lose aperture at about 75-80’. At 60’ I measured an aperture of about 80mm, at 30’ it’s about 75mm and at closest focus of 16’ it’s down to about 70mm. As I recall the Pentax was worse, with the effective aperture already below 70mm at 30’. The first photo on the left below shows the difference between the 20x exit pupil size at infinity focus and at 16’. Part of the reduction in exit pupil is due to increased magnification at close focus and the rest is caused by the prism aperture blocking the edges of the objective. If at infinity focus the scope acts like a true 20x82, then at 16’ it’s effectively more like a 22x70.

The objective has 4 elements and a focal length of 464mm. That is, not so coincidentally as you will see later, about the same focal length as Swarovski scopes. There is a triplet up front consisting of a cemented doublet, closely air-spaced with a singlet and then down the tube close to the prisms there is another singlet in about the position a focusing lens would occupy. According to Zen there are two ED elements, but the type of ED glass is not specified. I don’t know of another scope using this particular configuration. The Pentax 80ED has a fixed singlet near the prism, but uses a doublet up front. All of the current alpha scopes use fixed triplets with moving focusing doublets.

I’ve included some star-test photos, which show a progression from intra-focus on the left through best focus at the center to extra-focus on the right. Unfortunately this is the best I could do, thanks to air turbulence. The diffraction patterns were much clearer through the eyepiece. There are a couple of items of interest that can at least be glimpsed in the photos. First, notice the flat spot on the outer edge centered at 4:00-5:00 in the intra-focal pattern. That appears to be a prism edge impinging on the light cone. It causes a diffraction spike that can be seen dimly at about 10:30 at best focus and in the close extra-focal pattern (right of center). That spike was more evident at the eyepiece than it appears in the photos. Second, notice the better defined intra-focal rings compared to the extra-focal rings. A perfect scope would show identical rings on both sides of focus. I believe the asymmetry in the Zen star-test comes mostly from sphero-chromatism, the form of spherical aberration that varies with wavelength. It causes the unfocused purple smear of color between the extra-focal rings that reduces their definition. While still not perfect, the symmetry of the extra and intra-focal rings is improved when viewed through a green filter that shows spherical aberration for a narrow band of color. Spherical aberrations are not too surprising in a fast scope like this. I also found it difficult to achieve a really good focused star. A perfect scope at high magnification shows a nice round airy disc surrounded by a clean first diffraction ring. Through the Zen a highly magnified star point always showed some flaring and asymmetry similar to what you see in the focused star image at the center. The impinging prism edge and the spherical aberrations were present in all three samples of the scope I tested, so I think it’s safe to conclude that they are characteristics of the design.

The spherical aberrations are probably doing most of the damage to the image quality at high magnification when the Zen is compared to a more “perfect” scope of the same aperture. I measured the resolution with the USAF 1951 resolution test pattern at 1.6 arc seconds. Not bad for a 82mm spotting scope, but not quite diffraction limited, which would be more like 1.42 arc seconds. At first glance the image at 60x looks good, but when directly compared to a scope with better corrections of about the same aperture (Takahashi SKY90 Fluorite APO reduced to 80mm) the image through the Zen appears somewhat degraded. This is why a reference scope of known quality is so important for comparisons. None of us has a built in sense of exactly how good a 60x image in an 82mm scope should look. For my eyes, the Zen at 60x loses about 1 element on the USAF chart (-12%) compared to the Tak and the image has the kind of gauzy appearance I associate with the presence of spherical aberrations or other defects. Chromatic aberration, on the other hand, appears well enough corrected for 60x. There is only a very little longitudinal CA visible. The color correction (like most ED spotting scopes) is not at the level of the best astronomical APO refractors, but it also doesn’t need to be that good for birding magnifications.

The USAF test patterns below are tight crops of photos made through the scopes using a Nikon D40 with a zoom lens set at 80mm. The left side is the Zen with its zoom eyepiece set at 60x compared to the Takahashi “80mm” on the right with a Baader zoom set to 60x. The Tak image is reversed because it uses a simple star diagonal for image erection. The photos don’t quite reveal the full resolution visible at the eyepiece through either scope, but the difference in image quality as it appeared to my eye comes across pretty well. What the photos don’t show is the difficulty one encounters trying to focus a scope with significant spherical aberration. No matter where the focus is set there is always some light from some part of the objective that remains out of focus. A scope with low aberrations, like the Tak, snaps into a definite sharp focus at 60x, but trying to find a completely sharp focus with the Zen at 60x involves a search back and forth that never ends. You think you’ve found the best focus, then you look again and it’s gone. The best 80-82mm alpha scope specimens would have images at 60x similar to the Tak and a larger aperture scope like the Kowa 883 would be even brighter and sharper than the stopped down Tak. The difference in image quality between the Zen and the Tak didn’t completely disappear even at the lowest magnification I used for comparisons (25x), but as magnification drops below about 35-40x the aberrations take less of a toll and the Zen image looks quite respectable, sharp enough to be largely indistinguishable from the Tak except under very close scrutiny.

The Zen’s color bias is slightly warm. The photo of a square within a square below shows a piece of white photo paper in sunlight. The square in the center is an image of the center of the same piece of paper photographed through the Zen scope. Just looking through the scope I had very little sense of this slight warm tint.

Part 2 – The Zoom Eyepiece

I discovered, when I compared them, that the Zen 20-60x zoom eyepiece is a direct copy of the Swarovski 20-60x zoom. The focal lengths, lens diameters, overall dimensions and everything else I could measure are the same within the margins of error of my kitchen table and backyard methods. The photos of the two eyepieces placed side by side (Zen on the left) show identical reflection patterns of the camera flash returning from the lens elements. This only happens if the optical formulas are identical. So, whatever has been said about the excellent Swarovski eyepiece also applies to the Zen, which is such a faithful copy that I doubt anyone could tell the difference between the two. Both are very sharp and bright at every magnification with excellent off–axis performance. As is often the case with spotting scopes, it’s the objective and prisms that limit the high magnification performance, not the zoom eyepiece. Charles at Zen-Ray does not recommend it, but as you can see in the photo that shows the bayonets, the mounts are so close that Swarovski eyepieces will fit the Zen scope (but not engage the locking pin) and probably vice versa.

I measured the eye relief and AFOV of the Zen eyepiece at the magnifications marked on the barrel. Eye relief was measured from the rim of the eyecup. It would be 6mm longer measured from the glass of the eye lens. AFOV measurements were done using the panning scale on a tripod head. These are the true angles subtended by the apparent field including any distortion, so they cannot be compared to specs derived mathematically from the real field.

20x, AFOV – 40 degrees, ER – 17mm
30x, AFOV - 48 degrees, ER – 12mm
40x, AFOV – 55 degrees, ER – 11mm
50x, AFOV – 62 degrees, ER – 13mm
60x, AFOV – 66 degrees, ER – 14mm

I should mention that I ran into a birder with a Vortex 85mm Razor scope this spring. I didn’t have the Zen for direct comparison, but I noticed that both the Vortex scope body and its zoom eyepiece looked very much like the Zen, including what looked like the very same “Swarovski” bayonet mount.

Part 3 – The 30XW eyepiece

This is another copy. This time the eyepiece being copied is from the Nikon SE series binoculars. The Zen version does have a slightly wider apparent field, but other than that I could detect no significant difference between the two when I mounted them on the same scope. You might expect this eyepiece design to deliver really good off-axis performance, but in fact it turns out to be more adequate than outstanding when used on a scope. There is some off-axis astigmatism, which oddly reaches a peak around 20 degrees from the center, then gradually diminishes toward the edge. The off-axis performance is OK, but not in the same class with the premium wide field astronomical eyepieces I have on hand for comparison (14mm Pentax XW, 19mm Televue Panoptic) and not quite as good as a 17mm Baader Hyperion. The Zen is quite small and light for a wide field eyepiece with long eye relief. The field is wider and eye relief longer than the zoom at 30x, but off-axis aberrations are worse, so the sweet spot is actually smaller. Too bad Zen didn’t copy the superb Swarovski 30XW, which is better in every way, but that would surely have resulted in a much more expensive eyepiece. The Swarovski 30XW will fit the Zen scope with excellent optical results, but it doesn’t engage the locking pin, so it may not be completely secure (once again, not recommended by Zen-Ray).

Eye relief measured 15mm from the eyecup, 21mm from the eye lens glass. AFOV was 59 degrees. That’s about 2 degrees more than the SE eyepiece measured the same way.

I notice that the Vortex Razor 30XW eyepiece shown on the Eagle Optics website looks very much like the Zen-Ray 30XW and has the same specs.

Part 4 – The Eyepiece Adapter

One more bit came with the Zen scope. It’s described as a 1.25” eyepiece adapter, but it won’t actually accept 1.25” eye barrels. The idea is to unscrew the eyepiece body from its barrel and then thread the eyepiece body onto the adapter. Unfortunately this will work only for the eyepieces that happen to have a male thread of the right size. Many of the most desirable astronomical eyepieces have field lenses in the barrel, so the barrel shouldn’t or can’t be removed. Charles is aware of the problem, so some modification of this adapter might turn up in the future.

I hope, by pointing out some faults, I haven’t left the impression that I have a negative opinion of the Zen scope. Provided you get a specimen as good as the cherry review sample here, the $1200 price of the Zen will buy you a superb zoom eyepiece, combined with scope optics that are good enough to stand comparison to average specimens of premium spotting scopes of about the same aperture (especially the Swarovski 80-HD since it uses essentially the same eyepiece). It’s true that the image quality, even of this cherry sample, is inferior to cherry samples of premium scopes, especially larger aperture scopes like the Kowa 883, but given the sample variation in expensive scopes you could wind up buying an alpha specimen with worse optics than this particular Zen. As ever, I’m afraid obtaining a good scope still comes down to finding a good individual unit no matter how much you’re willing to pay.

Finally, I’d like to thank Charles at Zen-Ray for patiently responding to my various quibbles and complaints over the last 5 months. He was always the perfect gentleman and a pleasure to deal with.

Henry Link


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Last edited by henry link : Saturday 11th June 2011 at 13:54.
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Old Saturday 11th June 2011, 13:47   #2
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Forgot to include the photo of the front end of the Zen and Swarovski zoom eyepieces.
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Old Saturday 11th June 2011, 15:30   #3
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Henry....Hi..thanks for The review..I was looking forward to read it .
I do own the scope ,and have found pretty much the same results with my sample.
I had mixed results with my star testing,..with a faulty artificial star in my first test (a weird shape pinhole?..or too big)...but many other tests with different pinholes and actual observation of real stars in clear,crisp nights,Showed consistent results that are very close to the images that You posted.My scope shows no diffraction spikes when is In focus ,and creates sharp pinpoint images of stars.
The interruption that creates the flat area in the star test is also there and the slight loss of definition in the outside focus rings is there too.
This last pattern,that you identify as sphero-chromatism,I have found in most of the mid-high quality scopes that I have used,(pentax 65ED,Vixen Geoma ED),and to some extent to the Kowa 824 I used to own.(.altough I only had a 50X fixed power eyepiece to Star test the kowa,and that is insufficient magnification to test the scope)..What I mean,is that I have never used a quality astronomical scope ,and I am more than used ,when doing these test,to the image outside of focus being dimmer and less defined than the image inside of focus,and I think this is pretty much what prism scopes show..So it didnt surprised me..neither I think It surprised You that your Tak had more resolution at 60X..the other case would have been prodigious!!!!
The image at 60X gets a bit softer,but is worth of mention the excellent control of CA at that power...What truly surprised me is the quality of the boosted images (using my 8x binos..sharp old swift ultralites)..I was impressed with brightness at 160X and even 240X ..CA at such powers is still very well controlled and the image very usable.
I have done this(8x boost the image with my binos) with other scopes in the field to try to get that invisible bird in the top of that distant tree,and I always used to get VERY dim and super soft images at 160X..but the ZEN was fun to experiment with, in this regard.

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Old Saturday 11th June 2011, 16:27   #4
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I ordered a ZEN spotting scope yesterday. It is scheduled to deliver in the middle of next week.

Have you measured the actual diameter of the objective. I have been doing the paper study of the specs for ZEN ED2 and Vortex Razor. Everything is almost identical, except of the objective size. Razor is 85mm, ZEN is 82mm. According to another thread, the ZEN takes 86mm UV filter. This makes me wonder whether zen-ray has a physical objective diameter of 85mm too? The 82mm is the effctive aperture at infinity focus? Well, I guess I will find out in a few days.
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Old Saturday 11th June 2011, 16:50   #5
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Henry,

Thank you for the excellent write-up. The feedback from you during the initial testing resulted in a drastic change of process on how the telescope is assembled and tested, even on how it is packaged. I am very grateful to you for your help along the way.

For the 1.25" adapter, a new design is being developed so it can be truly universal for all 1.25 astronomical EPs.

Best Regards

Charles
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Old Saturday 11th June 2011, 20:09   #6
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Quote:
Originally Posted by mayoayo View Post
...I am more than used ,when doing these test,to the image outside of focus being dimmer and less defined than the image inside of focus,and I think this is pretty much what prism scopes show..
Yeah, spherical aberration is all too common in birding scopes, but some specimens of some models manage to correct it, even with prisms. I've personally seen an essentially perfect Kowa 823 and have heard reports of similar Kowa 883's and Nikon 78 and 82ED's, so it is possible. I would demand no less from any $2000+ scope, with or without prisms.

NWBirder,

Sorry, I didn't measure the objective from the front.
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Old Saturday 11th June 2011, 22:21   #7
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Henry, I thought you had an AP Traveler for your reference scope? I had three Tak Sky90's and spherochromatism was fairly evident at its native focal length in every sample. Using a 1.25" prism diagonal instead of a 2" mirror seemed to mitigate it somewhat, but then I lost all those great widefield views.
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Old Saturday 11th June 2011, 22:44   #8
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Rick,

I have an AP Stowaway, which I used some as a reference, but I mainly used the Tak because its focal length is closer to the Zen, so I thought it would be a fairer comparison. The importer supposedly hand picked my Tak by star-test after I returned two bad ones. It's still not as good as the Stowaway, but happily it's spherical correction, which is not so good with a mirror, is just about right when a Baader/Zeiss prism diagonal is inserted in the optical path.

Henry
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Old Sunday 12th June 2011, 13:30   #9
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Hi Henry, Thanks for taking the time to review this scope, I know it has to take a lot of your time to do it. Excellent Review!!!

Sounds like this Zen-Ray ED2 82mm would make a very good spotter esp. after comparing it to a Tak 90 stopped down to 80mm. I think "most" people would be happy with it.
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Old Monday 13th June 2011, 00:46   #10
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Henry,

As the others have stated, nicely done. Your reviews are always exceptionally thorough, unbiased and very informative. I enjoy reading through them as I feel as if I learn or thing or two not only about optics in general but how to evalute them.

FWIW, I did receive the scope, etc... a day or two ago and had a few hours yesterday to compare it with the Theron and the Celestron. I would love to see you do a similar review of one or both of those scopes in the future. Maybe you and I could arrange something.

Please do keep up the excellent posts.
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Old Monday 13th June 2011, 10:47   #11
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Henry,

Thanks once again for a superb review. In addition to being an excellent and balanced assesment of the scope, it ends up being such a thorough and clearly-written essay on scope testing and the parameters that influence the quality of a design and the specific sample that it should be made mandatory reading for anyone thinking of starting a "which scope should I buy" thread.

My experience with star-testing alpha and non-alpha spotting scopes pretty much parallels yours. Spherical aberration tends to be a problem with even the best models and makes, but like you, I have seen examples of virtually SA-free scopes from Kowa (823 & 883), Swarovski (AT 80 HD, ATS 65 HD, ATS 80 HD), Nikon (Fieldscopes ED III A 60mm, ED 78 A & ED 82 A), Zeiss (only a couple of specimen of the 85mm Diascope - most of the ones I have seen have quite a lot of SA, as do all of the Leica 82 Apos I have yet seen) - as well as some Opticron ES scopes. Of all of the above, I have also seen samples with more aberrations than I care to start listing here. As an example of what I would consider a really good sample, attached are two photos taken of an artificial star through a cherry Nikon ED 82 A, left one taken outside focus and right one inside focus. I think they show that a prismatic scope designed and excecuted right can provide superb image quality despite the inherent complexity of the concept.

Kimmo
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Old Monday 13th June 2011, 15:19   #12
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Thanks guys!

Frank, if your Theron and Celestron scopes are loaners I'd be happy to test them if the importers are agreeable. On the other hand, I'll also be happy to save myself some trouble and just read your results for the same tests I would do. Resolution on the USAF chart and star-tests should come out the same for both of us.

Kimmo, thanks for posting the Nikon photos. Now when are we going to see some new reviews from you?

Henry
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Old Monday 13th June 2011, 15:40   #13
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Henry,

I will give it a go this week and let you know. Both are mine at the moment though I may return the Celestron. You are right of course with regard to the testing. Your interpretation of data and wealth of experience is something I could not match though. Lets discuss it again later this week after I get to run them through similar tests.

Thank you Henry, again, for all you do.
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Old Tuesday 14th June 2011, 04:10   #14
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Henry,

Well done as usual. There is always something to be learned from one of your tests. Thanks.
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Old Tuesday 14th June 2011, 19:00   #15
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Quote:
Originally Posted by kabsetz View Post
As an example of what I would consider a really good sample, attached are two photos taken of an artificial star through a cherry Nikon ED 82 A, left one taken outside focus and right one inside focus. I think they show that a prismatic scope designed and excecuted right can provide superb image quality despite the inherent complexity of the concept.

Kimmo
It would be helpful to know brief details on the eyepiece/doubler/tripler combination and camera magnification.
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Old Wednesday 15th June 2011, 11:05   #16
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The eyepiece is 25-75x MCII zoom set at 75x. No booster or doubler. Camera was Nikon E 4500, the exact settings I don't recall, but the camera zoom had to be used to prevent excessive vignetting. I didn't manage to take good enough pictures at best focus.

Hope this helps.

- Kimmo

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Old Wednesday 15th June 2011, 19:30   #17
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That's great thanks. I have a Kowa 824 with 32x eyepiece and I've tried star testing with 8x binoculars giving over 240x handheld. I can see something but I presume I need about 80x ideally. Is 60x from a zoom enough for star testing or ideally do you need a bit more?
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Old Wednesday 15th June 2011, 21:42   #18
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I have read that 1X per mm of aperture is the ideal formula...or was it 1.2X?..(100X in an 82 scope?)
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Old Wednesday 15th June 2011, 23:04   #19
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1x/mm as a minimum, 2x/mm for high quality optics. Star testing a fieldscope system is tricky business. One really never knows the source of the defect with 100% certainty. Could be the objective, prism, eyepiece, or the booster. Using a camera lens to photograph it adds another layer uncertainty.
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Old Thursday 16th June 2011, 00:43   #20
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The common defects in an 80mm scope will be visible at 60x. Nearly all the problems that show up in star test will be in the optics train before the eyepiece. It may be the objective or the prisms or both but that doesn't matter too much since you can't separate them.
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Old Thursday 16th June 2011, 00:52   #21
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I see that FrankD has revealed that Zen-Ray is about to announce a 25-50x wide angle zoom. I tested a prototype, but unfortunately I don't have much time to write about it now. I'll say that that I was surprised to see a healthy dose of barrel distortion at the low magnification end, something I don't think I've seen in an eyepiece before. Also, unlike most zoom eyepieces the eye relief is shortest at the lowest magnification. I'll see if I can find my notes and write a little more tomorrow.
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Old Thursday 16th June 2011, 02:06   #22
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Henry,

Charles gave me the go-ahead to mention it a day or two ago which is why I posted about it. I thought you might have more to say on it than I at this point.

I was surprised to see the same thing you did with the barrel distortion. I picked it up when panning with the scope. Stationary I did not notice it as much. At 50x it is greatly reduced and I just cannot believe how sharp and bright the image is at the 50x setting. Impressive!
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Old Thursday 16th June 2011, 13:35   #23
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Here are some measurements of the AFOV and eye relief of the Zen 25-50x prototype. Keep in mind that the final production version may be different.

AFOV is the "true" apparent field including distortion. In this case that causes a somewhat smaller apparent field than expected at low magnification because the distortion is barrel rather than pincushion. Eye relief is measured from the rim of the eyecup. It would be about 4mm longer measured from the glass of the eye lens.

25x AFOV - 54 degrees ER - 10mm
30x 60 degrees 11mm
40x 65 degrees 13mm
50x 68 degrees 14mm

If you compare these numbers to the 20-60x you find that the eye relief of the 25-50x is shorter at magnifications up to about 35x, but longer between 35x and 50x. I should also mention that the rubber eyecup design of the 20-60x has a 6mm recess instead of 4mm, so the difference in optical eye relief is 2mm more in favor of the 20-60x than my measurements from the rim.

I compared the 25-50x zoom set at 30x to the 30xw eyepiece. The zoom had a slightly wider apparent field and much better off axis sharpness. Longer eye relief was the only advantage I could see for the fixed magnification 30x.

I agree with Frank that the zoom is bright and sharp at the 50x setting, in fact brighter and sharper than the Zen scope allows you to see. I didn't find it to be any better than the 20-60x set at 50x. Neither compromises the scope's performance. It's the scope that compromises the eyepieces.

I also briefly compared the Zen zoom to a Swarovski 25-50x zoom in a store. There were similarities in the reflection patterns, but there also appeared to be some differences and some optical characteristics were clearly different. The Swaro does not have barrel distortion and its eye relief is longer. Perhaps because of the short eye relief the Zen does not display the tendency to blackouts that I notice in the Swarovski.

If I were buying the Zen ED2 scope I would probably choose the 20-60x just for the extra detail visible at 60x. If you are inclined toward a 25-50x wide field zoom this is an impressive eyepiece, with a couple of caveats. If you wear eyeglasses the eye relief may be too short to take full advantage of the field and some people are going to experience "rolling ball" when panning because of the barrel distortion.
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Old Wednesday 22nd June 2011, 20:57   #24
mayoayo
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"I agree with Frank that the zoom is bright and sharp at the 50x setting, in fact brighter and sharper than the Zen scope allows you to see. I didn't find it to be any better than the 20-60x set at 50x. Neither compromises the scope's performance. It's the scope that compromises the eyepieces."

Henry Link,post 23,paragraph 6#

Hi there...I got the Swarovski 30XWA today..It is the older version,without a locking pin retainer,and does fit the ZEN bayonet perfectly.The fit is secure and tight.It is a small,lightweight eyepiece too,a bit taller that the Zen 30X but not larger ...The eyepiece JUST ..I mean..I fell in love instantly..beautiful ,amazing,you name it...
the 20-60X Zoom might be a superb eyepiece,but in my opinion,after today´s brief observation, does Not bring everything the scope is capable to the table,neither does the ZEN 30X,..The improvement is SO evident that there is no need to side by side comparing the views,..I can clearly tell that the zoom @ 30X doesn´t show this kind of detail..plus the image snaps in focus positively...The Swarovski 30XWA view is about as wide as the Zen 30X,but with better edge performance,and better performance in every other regard,including CA..Within the distortion free area of the image,probably about an 85% ,that is already sharp,there is a central Sweet spot,not huge,but large enough,and very, very SHARP..crispness..detail...texture..contrast...All there..

I love it..I catched a kestrel flying far,far ,far away ,while viewing from my roof ,and the view and detail impressed me, got me excited about the scope, and in other words,Convinced Me!...
I must say that ,using the ZEN eyepieces, I was happy with the view ,but not impressed to the WOW factor..today I WOWED!..
So at the moment I disagree with Henry Link in His view ..I see that the limiting factor ,in my unit at least ,was the eyepiece....It was good ,but today ,with a different eyepiece(an exceptional one)the scope showed exceptional performance.

Last edited by mayoayo : Wednesday 22nd June 2011 at 21:25.
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Old Thursday 23rd June 2011, 00:02   #25
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mayoayo,

I should probably allow you to get past the WOW state before I even agree that we disagree.

As you might guess I would prefer to read the results of a controlled test rather than an impression. A line pair chart to quantify the smallest visible details would be good and, even better, a booster scope placed behind the eyepieces to magnify any degradation of the 30x image caused by one or another of them. It really would take a very poor or defective eyepiece to limit the axial detail visible in this scope at any magnification, so once you've recovered from being WOWed by your new eyepiece, maybe you could do a more methodical test to determine whether your Zen eyepieces are really that bad.

Henry

Last edited by henry link : Thursday 23rd June 2011 at 01:09.
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