CN Report: Oberwerk Ultra 15x70
Posted 24 October 2006 - 02:18 PM
You have been responsible for some truly GREAT binocular articles in recent years , but to my mind , THIS one beats them ALL !
It is , in a sentence , simply THE most comprehensive , THE most informative and THE most well presented binocular REVIEW / ARTICLE I have EVER had the pleasure of reading .
I've read whole BOOKS which contain FAR less information !
Thank you for provided such a masterpiece FREE of charge and I suppose it would be superfluous to say " well done " , but I'm going to say it anyway :-)
WELL DONE , " Professor " Ed Zarenski !
Regards , Kenny
Posted 24 October 2006 - 02:32 PM
I especially like having some explanation of some of the technical aspects of gathering data for comparison.
I remember various bits of it from a couple of ealier posts in the binocular forum, but having it all gathered together is nicer.
Pretty well confirms my suspicion that these Oberwerk Ultras are pretty darned good, especially considering their cost. I hope to enjoy mine for many years to come.
Posted 24 October 2006 - 04:36 PM
Thanks for an exceedingly comprehensive reveiw of these Binoculars. If I didn't already own a pair I'd go out and buy a pair right now! Even though I don't test binoculars like you, I could tell right away these were better than any of my other bino's.
The binocular forum has over 200 minireviews available. I would have to say this is an example of a MAXI-review! Again, great job and thanks.
Posted 24 October 2006 - 04:45 PM
Thank you for the comments.
I especially like having some explanation of some of the technical aspects of gathering data for comparison.
That's something I provide in all my reports. I'm sure by now a habit difficult to break. As I see it, they're not just equipment reviews, they're explanatory articles. (At least, I always hope they are).
Posted 24 October 2006 - 05:14 PM
(you've seen that graemlin from me more than once) ...
... and it is well-deserved every time.
But this time, as Kenny said first, you outdid yourself. Excellent article/review. I think the reason why we do not see many reviews as good as this one is because very few binocular observers possess your expertise in measuring/testing the technical aspects of the optics.
Even though my 22x85 model is not the same as the 15x70 Ultra, it is descended from the same lineage. After reading your report, I am confident I made the right decision to purchase one of these new UO/Kunming premium binoculars.
In short, this Oberwerk Ultra is a very good binocular. I usually like to refrain from doing so, at least until I've had many weeks and opportunity to try out something new, but in two months from what I've seen and recorded so far, I'd recommend this Oberwerk Ultra 15x70 to anyone.
That is the closest thing to a "glowing" review that I have ever seen posted under your name. It must surely be a quality binocular.
Thanks for sharing your work and clear dark skies...
Posted 24 October 2006 - 07:57 PM
Posted 24 October 2006 - 11:03 PM
Posted 25 October 2006 - 10:50 AM
Kenny took the words out of my mouth - that's THE best review of any item I've ever read (actually, I'm still reading it)!
Posted 25 October 2006 - 02:16 PM
Posted 25 October 2006 - 02:53 PM
IIRC, the GO20x80 has Tfov 2.9°. The Oberwerk Ultra 15x70 has ~4.4°
But probably more important in this instance is sharp field of view. The Ultra15x70 has about 10% wider sharp fov compared to the GO20x80. So for instance, you would compare the Go at 70% to the Ultra at 80%. Now we see the GO has 2.9 x 70% = 2.0° of view comparable (or equal in distortion) to the Ultra at 4.4 x 80% = 3.5°. The 15x70 Ultra has a far wider sharp view showing 3x as much area of sky than the 20x80.
The 15x70 also has larger exit pupil, and both are within normal range for most users. A benefit under darkest skies.
While the same heavier mount can easily be used for both the 5#5oz. Ultra15x70 and the 7.5# GO20x80, the Ultra can also be used on lighter mounts while the GO20x80 cannot. The 3130/3011 works for the Ultra. That would be pushing it with the GO20x80. The Orion Paragon would work for the Ultra15x70, not for the GO20x80. So you could get away with $75-$150 less mount.
I had this to say about the GO20x80 in my previous article:
"For the 7.5# GO 20x80 I used a Bogen 3246 with 501 head or a Bogen 3011 with 3130 head. The 3246/501 was as solid as a rock. The fully extended center column was stable. The 3011/3130 with fully extended center column was the least capable of all these mounts. Settling times took the longest and movement of the head was difficult. I consider this 7.5# 20x80 too much for the 3011/3130 tripod/head setup."
The 20x80 reaches deeper, it's certianly no slouch, but the 15x70 does a lot of things good. It could be the right choice for a lot of people.
Posted 25 October 2006 - 04:28 PM
I think this is a VERY important point , which can EASILY NOT be realised by a cursory glance at comparitive specifications , when being expressed in the way as is traditional or customary .
Even leaving aside the MOST important aspect of SHARP FIELD of view , I think SOME people ( although almost certainly not one so astute as Mardi , as it happens ! ) tend to UNDERESTIMATE what a difference of 1.5 or 2.0 degrees TFOV actually makes .
One simple thing I did years ago was to take a compass ( as in the hinged instrument variety for drawing circles , etc ) and on a sheet of plain A3 paper , drew circles to represent True Fields Of View of some commonly found in binoculars , ranging from 2.5 to 8.5 degrees .
For example , for a TFOV of 4 degrees , set the compass to 2 inches and draw a circle .
For a TFOV of 6 degrees , set the compass to 3 inches , and so on .
It provides a very handy quick visual reference for comparing AREAS of view one can expect to see through various models .
It is handy to have a few copies of these , on which one can draw circles of AREAS Of SHARP image , as reported by reliable source reviewers , of which there are none I am aware of MORE reliable than EdZ .
Shading out the outer , " out of sharp " areas then provides accurate representative impressions of the TRUE expanses of sky ( or landscape for daytime users ) which can be expected to be ENJOYED through any given model .
I recently found myself in a situation of having to make what was for ME , a VERY difficult decision .
I had decided I wanted a Nikon Superior E in either 10 x 42 or 12 x 50 , but was in no position to get BOTH .
Although OTHER important factors , not least HAND - HOLDABILITY did play a major part in my decision making , it was after a whole night of chilling out over a glass or two of wine , in a very relaxed atmosphere , occasionally looking at TWO simple circles drawn on a piece of paper , and placed right in front of me on a coffee table , that I FINALLY decided to go with the 10 x 42 SE !
Regards , Kenny
Posted 26 October 2006 - 12:00 PM
Kenny, far be it for me to disparage anyone's preferences for wide sharp fields!! I can certainly understand a certain advantage in ease of star hopping that an additional degree or two would provide. Aesthetic-wise, to each their own and all that.
The wide field sharpness requirement/preference whatever, is less easy for me to understand the logic of however, especially at the cost of the degree of decreased center field target definition, as Ed related in his comparison report. As to corrected fov, 2degree corrected fov (Garrett 20x80 per Ed's numbers) seems to well encompass all but a half dozen or so of all the objects listed in the deep sky 600 map (and the full extent of those larger objects are not typically even visible in small apertures). And aren't objects best positioned for observation in the center of the field>? Such positioning is virtually on an instinctual level for humans, is it not? I guess this is why i am confused by the heavy emphasis typically placed upon outer field sharpness. I suppose there's an aesthetic justification possible, or an observational preference for observing star fields perhaps that could somewhat rationalize the cost/benefit of this characteristic. There's no way to argue the former (being subjective) and the latter seems rather an esoteric pursuit...seems like most observers are more target oriented than sky surfers but this could be a misunderstanding on my part on how people generally use binoculars.
Anyway, thanks for the responses.
Posted 26 October 2006 - 01:27 PM
For me, I strongly desire a certain view aesthetic, and it is why I am drawn to wide-field (3°+) low-power views. I will try to explain exactly what aesthetic I am chasing :
1) sprawling, packed star fields (Cygnus, Sagittarius, etc)
2) visually-interesting open clusters, M7, M50, M45, etc.
3) optics that have excellent color rendition to see color (the proper kind) in stars.
4) optics with excellent sharpness that show stars as nice, crisp pinpoints with little/no flaring/spiking. Stars, IMO, should be nice round bead-specks.
5) a large usuable sharp field that has the above 2 characteristics. Even though the actual target may be centered in the "sweet spot" of the FOV, the remainder of the field is important for aesthetic reasons. Without distracting aberrations that distort the stars in the middle/outer field, the view can become more immersive in my opinion. A tiny but important part of the viewing "interface" or experience is lost when there is a visibly noticeable boundary of aberrations in the field. IMO, aberrations should be strongly controlled until very near the field stop.
I have seen such views in telescopes belonging to others. I once saw M50 in a 12" dob with a premium eyepiece and it blew me away. Words like "tack sharp" and "spacewalk" come to mind. I am chasing that aesthetic in a binocular. This may be a futile chase, given the very nature of fast binocular optics, but these new UO/Kunming/Obie/GO/AP Series-8 binoculars are another step in that direction.
I may eventually replace my 15x70 Skymaster with a 15x70 Series-8 Ultra/Signature bino.
Clear dark skies...
Posted 26 October 2006 - 03:29 PM
To my mind , ANY area within a binocular's field of view which is NOT sharply seen , is more or less wasted .
Particularly , that is how I felt about the view through the SUPER WIDE FIELD Orion Expanse 7 x 32 , my full review of which can be seen in the CN Binocular's MINI - REVIEWS section .
On the other hand , binoculars I've looked through which provide very narrow apparant fields of view , for example Pentax 20 x 60 ( 41 degree AFOV ) and numerous zoom binoculars , simply do not satisfy me .
I suspect it may be easier to understand my preference if one considers that the great majority of my binocular viewing , and many comments I make about binoculars in general , applies to DAYTIME terrestrial use , rather than ASTRONOMY .
But even when looking at the night sky through binoculars , I still prefer to be looking through eyepieces which have AFOVs of at least 50 degrees .
I think that at around 60 degrees AFOV , my Zeiss 7 x 42 BGAT and Nikon 10 x 42 SE hit just about the " right " spot for me , for both daytime and night time use , without soft , distorted or unsharp edges becoming a DISTRACTION .
Clear skies , Kenny
Posted 26 October 2006 - 03:57 PM
Quite often I do detailed observing where a smaller field (and usually higher power) is necessary, but also, I can think many occasions and dozens of fields where I need 2° to 3°, at least a dozen in Cas/Per area alone.
I think often times binocular observers view groups of objects. I published an Observing article 100 Binocular Objects in groups. I would guess there are about 40-50 groups of objects in that article, many of which could not be observed with less than 2° fov. These are just the most common areas of object groups. For my own personal observing, I have dozens more groups not listed in that article.
When you use a binocular that has multiple aberrations that add up to 30-40 arcseconds of distortion outside that fov, it becomes not suitable for viewing. Several years ago I wrote reviews in which I classified the area of the fov as suitable for finding, suitable for wide field viewing, suitable for detailed observing. It's been a long time since I've used those designations. Basically, I'm measuring the same thing, only now, rather than put a subjective term to it, I provide a measurement for it.
These are just some reasons why I cherish a wider sharp field of view.
Posted 26 October 2006 - 04:23 PM
Makes me want to go out and buy them:)
But alas, money doesn't grow on trees.
Posted 31 October 2006 - 11:40 AM
They are a competent glass with good transmission and sharp images in the center 50% of the field. Great for casual MW starcloud scanning and also do a wonderful job on terrestrial viewing. The resolution and coatings make themselves immediately noticable.
This is to me an indication that the last barrier of Chinese optics, the coatings, has been overcome. These binoculars are IMO very high on the price/performance curve.
Two thumbs up....
Posted 05 November 2006 - 11:07 AM
Thanks again Ed
Posted 14 November 2006 - 02:50 AM
Posted 14 November 2006 - 12:15 PM
Welcome to the forum !
Yours must surely be the most UPBEAT first post anyone has ever sent to this forum !
I'm delighted for YOU that you are so happy , and pleased for EdZ that once again his painstaking work has reaped another just reward .
I'm sure he will be as pleased for you as I am , and hope you manage to keep in touch with the occasional update and observing report .
Clear skies ,
Posted 14 November 2006 - 10:54 PM
Posted 14 November 2006 - 11:39 PM
Posted 15 November 2006 - 06:18 AM
and thanks Keith for your comments.