Anonymous
Unregistered
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Hi all,
I’m new to this forum and would like some advice on the best place to purchase some binoculars.  This would be my first purchase of a big pair of binoculars with 70 or 80mm objectives. From looking at the forum, Oberwerk seems to be rated highly and are low cost, so looks like this will be my first buy.  I live in the United Kingdom and it looks like I will have to purchase from overseas as I am unable to find suppliers of large binoculars over here. This will be my first purchase over sea, so the company has to be reputable as I don't want to end up out of pocket. So any links to quality suppliers with good service welcome.
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Anonymous
Unregistered
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Do not despair George, all is in hand to bring in a batch of large binoculars to the UK from China this Autumn and you will not be nailed for the 30% duty/VAT payment that you surely will if you buy from the USA ! I have sent you a contact note privately.
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KennyJ
Reged: 04/27/03
Posts: 10082
Loc: Lancashire UK
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George,
A good place to check for used 70mm and 80mm binos is Chris Heapy's astro ads. Recently ther have been Fujinon 10 x 70s and Helios 15 x 70s going for very reasonable prices.
I have purchased two pairs via this site myself and have been delighted . Both as good as new and for 60% price new.
There is a company called Trentmann Products in the UK ( check out web site ) that already has a wide selection of big Chinese binos presumably similar to those sold by Kevin at Oberwerk and Bill Burgess , but when I contacted them I was told prisms are Bk7(not as good as BAK4) unless you pay extra for BAK4 . This put me off a bit but prices seem very reasonable . Incidentally Helios 15 x 70s are readily available from several retailers in the UK. These are the same product EXACTLY as Orion Little Giant 2 , but just cost about £70 less .
Regards and clearer skies than we are having in Lancashire.
Kenny .
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Two eyes and a preference to use both
Zeiss 7 x 42 BGAT
Captain's Helmsman 7 x 50
Nikon 10 x 42 Superior E
Swift Audubon Kestrel 10 x 50
Helios 15 x 70 Observation
Strathspey 20 x 90
Televue 76 APO
Zeiss 85 Diascope
Helios 102 f5 refractor
Various eyepieces barlows tripods mounts etc.
Panasonic Lumix DMC - TZ5 digital camera
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Anonymous
Unregistered
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Great, thanks for the info. If their are any more uk site selling big binoculars then please let me know. I am currently trying to find as many places preferably u.k based before i make my mind up what and where to buy. Trouble is being a newbie is making it very difficult for me to decide what to buy and where. At the moment it looks like i will be purchasing either oberwerk 11 or 15x70 or the oberwerk 20x80s standard. Mainly due to value and low price. I will check out chris heapy's astro adds. But am not very confident purchasing second hand due to risk of making payment and not reciving goods. looked at Trentman products limited but could not see any large binoculars on their web site.
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rboe
Numbfinger
Reged: 03/16/02
Posts: 39501
Loc: Phx, AZ
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At the risk of starting a war similar to front wheel drive vs. rear wheel drive; BAK-7 is generally superior in binoculars vs. BAK-4. Russ over at Denkmeier bino-viewers and some folks at Edmond Scientific (Edmund Optics now?) seem to back this up. Like front wheel and rear wheel drive; each has its' place where it excels. BAK-7 excels in prisms. But marketing has tossed a wrench into the works.
Ron
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Ron
NS11GPS
Pronto
16" dob
15X70 Obies
Edited by EdZ (02/06/04 12:04 PM)
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EdZ
Professor EdZ
Reged: 02/15/02
Posts: 12515
Loc: Cumberland, R I , USA42N71.4W
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The way I understand it is
Bak4 has a higher index of refraction so it bends light rays easier. Also, coating performance increases for glass with a higher index of refraction.
Bk7 has a higher Abbe number so it varies the index of refraction Less across all wavelengths of light, hence less chromatic abberation. But, it has trouble with the high angle of light cone in fast binoculars.
To me that sounds like Bak4 is the way to go for fast binoculars.
edz
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Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21
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Anonymous
Unregistered
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Well have now made my purchase. I await the arrival of new oberwerk 15x70s. However i did have to purchase from overseas and pay extra for shipping. Just home customs don't add money to the item as well.
Could not find shops in the u.k selling this size binoculars. Crazy.
Anyway from what i have heard, they are handheld (just about),but for better viewing I will have a go at building my own wooden mount to save money. Any recommended links to mount building.
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IDONTSEEIT
scholastic sledgehammer
Reged: 05/04/03
Posts: 900
Loc: NYC
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Ron, Ed, and all,
I have not done research regarding this BAK4 vs. BAK7 topic, however I just wanted to chime in in regards to also having read/heard conflicting arguments regarding which is superior. Right now, it seems, most advertisements for binocs, spotters, etc., all seem to be implying that Bak4 as being the best, however I've read ads, and articles, arguing that BAK7 is better   .
Right now I'm concentrating on solidifying my knowledge and understanding of some other optical aspects, but plan on moving to specific glass properties, sometime in the future.
Thanks!
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Joe,
C8 OTA on UA Unistar Heavy Deluxe
SV-102V on same UA Unistar Heavy Deluxe(not at the same time)
WO-Megrez 80-II ED on UA Microstar Basic
Orion 80ED on same UA Microstar Basic(also not at the same time)
Miyauchi Bs-60ic "Pleiades" 22X60
Orion UltraView 10X50's
Orion MiniGiants 12X63 & 15X63
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rboe
Numbfinger
Reged: 03/16/02
Posts: 39501
Loc: Phx, AZ
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Ed and Joe;
I found the orginal source over in Astromart from the vendor trying to pull BAK-7 from the dust bin and give it some respectability. Like all good arguements I had only part of the story. When I requested if I could repost his note and I explained why I wanted it. He said post away but did say that in general BAK-4 is superior for fast optical trains - like a binocular; but you have to treat binoculars as a whole system which pretty much means you can use BAK-X if the whole system is designed for it.
I have choosen to pluck a paragraph from his email and his earlier posting. I think I have to back track a bit. But not too far (whew!). Since the Astromart exchange got out of hand and it's not my intention to repeat that, I offer up the following quotes for discussion.
<quote>
In fact, show me an application faster than F/4 in amateur
astronomy where a binoviewer is used. So my point was that even with an F3.5
newt (we do have a few users!!), one must employ the OCS to allow focus.
F3.5 becomes F/4.4. There is no application faster than about F/4.3 or so.
Therefore, BK7 with superior Abbe number and transmission (yes, transmission)
is the preferred glass for OUR applications. Binoculars are another story and
since BAK4 has a higher refractive index and is therefore more efficient in bending
steep cones that BK7, it is preferred for many binocular designs.The objectives
of the Binoculars will determine which prisms must be used. Has nothing to do with
poor quality. It's a matching up thing entirely.
<and...from within the original posting> from Dick Buchroeder. I hope he doesn't mind if I share this since he is highly qualified to make a comment on this matter:
"When the objectives are say f/5, as they were on many of the WW2
binoculars, BK7 was the proper glass to use. When more compact designs,
with objectives at f/4 or faster (eg, the 10x80 German Flak glasses),
BAK4 was used." R.D.Buchroeder, PhD (Optical Sciences)
<end quote>
Since this has nothing to do with Where to buy a binocular, perhaps we should start a new thread if you want to bounce this around abit. I think we could all have some fun with it and hopefully learn something since optics is not my strong suit.
George; I have any earlier model of the Oberwerk 15X70 and I like them very much. They're not Fujinon's but they work very nicely indeed. Your's will be even better.
Ron
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Ron
NS11GPS
Pronto
16" dob
15X70 Obies
Edited by EdZ (02/06/04 12:14 PM)
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Anonymous
Unregistered
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George,
I am sure you will be delighted with the Oberwerk 15x70 and hope that the customs don't nail you but suspect they will because the declaration sticker on the box will say "binoculars". If it is intercepted at the Post Office, this may also add 10 days or so to the delivery time. Also handy if you have cash at home to pay the P.O man.
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Scott Hamilton
super member
Reged: 05/22/03
Posts: 144
Loc: Germany
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George,
so where did you end up purchasing your Binos? I for one,
would be interested to know.
Scott
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49 53 5 N
08 16 1 E
GSO 8" Dobsonian Reflector
KRONOS 26 x 70 Binoculars
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Anonymous
Unregistered
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Ron,
I got this e-mail from Zeiss.
BaK-4 prism glass yields the brightest images and sharpest edges over BK-7. Therefore, the finer glass in the BaK-4 design is of high density and virtually eliminates internal light scattering. Which in turn produces sharp, well defined images. BK-7 is a more homogeneous, bubble-free crown glass, and is easier to produce at a lower cost. Other advantages of Bak-4 is its improved color correction. Bak-4 is the best prisms to use in binoculars and binocular viewers (binoviewers).
Got this from OPT:
If you turn your binoculars around and look down the front lens towards the inside, you can see the difference between BK-7 and BAK-4 (much better prism quality). If the binoculars have BK-7 prisms, you can see a squared off side to the general roundness of the image. BAK-4 prisms show a truer round, which translates to better light transmission and edge-to-edge sharpness.
So in short.
Bak-4 = better light transmission, better sharpness, and better contrast. All this at a high price though.
BK-7 = Lower cost and easier glass to work with.
I will take the word of Zeiss any day of the week.
Don
Edited by EdZ (02/06/04 12:05 PM)
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IDONTSEEIT
scholastic sledgehammer
Reged: 05/04/03
Posts: 900
Loc: NYC
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Great info Don, I think Zeiss could be considered reputable as far as optics go 
I guess that settles any debate about bak4 vs. bak7, huh?
Thanks again for clearing it up for us, especially us greeners.
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Joe,
C8 OTA on UA Unistar Heavy Deluxe
SV-102V on same UA Unistar Heavy Deluxe(not at the same time)
WO-Megrez 80-II ED on UA Microstar Basic
Orion 80ED on same UA Microstar Basic(also not at the same time)
Miyauchi Bs-60ic "Pleiades" 22X60
Orion UltraView 10X50's
Orion MiniGiants 12X63 & 15X63
Edited by EdZ (02/06/04 12:05 PM)
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rboe
Numbfinger
Reged: 03/16/02
Posts: 39501
Loc: Phx, AZ
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Don;
Thanks for the feedback. That is very interesting from Zeiss and I'm inclined to take their word too. But being a vendor you have to add some salt to that. The old "Trust but verify" theory. However; their products speak for themselves and you can't argue with that.
Regarding OPT's comments; I'm wondering if that clue is due to a physical shape vs. tranmission properties - I need to try that trick on my bino's.
Ziess' statement that BAK-7 is more homogeneous and bubble free, is that compared to BAK-4? If so, I would be inclined to think BAK-7 superior just on those properties alone since bubbles and poor homogeneity will introduce light scatter. Clearly that is not the case so maybe it was just a poor choice of words.
Too bad we don't have one of those ray trace programs generate spot diagrams for binoculars vs. bino-viewers. You could easily see the difference you are paying for - at least on paper. With my eyes I'm not sure I could in a real world test!
Thanks again Don!
Ron
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Ron
NS11GPS
Pronto
16" dob
15X70 Obies
Edited by EdZ (02/06/04 12:06 PM)
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Anonymous
Unregistered
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Back to one of the original questions...
"...but for better viewing I will have a go at building my own wooden mount to save money. Any recommended links to mount building?"
I'd be interested in this also...
Tom (great discussion about BAK-7 vs. BAK-4 though)
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Anonymous
Unregistered
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Hi Scott,
Sorry for the delay in replying.
In the end I decided to buy from Kevin at oberwerk. I bought the oberwerk 15x70s mainly due to the recommendations on this site and because kevin checks them before dispatch. I was very happy with the binos and they appear to be well collomated. However it's not all good news when you take into account the costs of V.A.T, clearance fees and shipping costs to import the binos into the United Kingdom  . This alone came to 2/3 the cost of the binos, which were $149. I just hope they don't develop any manufacturing faults while under guarantee, as it would not be worth the high cost of shipping to send and receive them back. This is one reason why i wanted to buy here in the U.K. Unfortunately all my searches with google pointed to sites in the U.S.A for big binos. Also i did not want to take the risk buying second hand.
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Anonymous
Unregistered
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George,
I would also add my congratulations on your recent bino purchase. If you have any problems with the binos please send an e-mail to Kevin at Oberwerk before sending them back. I understand that he is able to give corrective instructions via e-mail (or phone I would imagine if warranted) for general repair/maintenance issues. It is indeed unfortunate that there was not a dealer in the UK where you could have secured a similar satisfactory purchase. Not that I am knocking doing business with the U.S., I just think there is a comfort level in being able to walk in to the dealer where you purchased a piece of equipment and work out corrections. At any rate, the 15x70 should serve you well. If they work well on arrival they should do nicely.
Tom, As it regards building a bino mount. There are instructions on building a parallelogram bino mount (probably the most popular type) in the book "Starware" by Philip Harrington. In addition, if you go to Google and type in, "Binocular mount" you will get quite a number of hits. Sort through them until you find building plans for binocular mounts. Actually, you might even try entering the term, "binoculars mount construction" or something similar.
I am presently in the process of building my own binoculars mount for my 4.6 pound binos from plans (more like idea sketches) I found on the web. One of my goals was to keep it all under US$50 (minus tripod). If it works I will be happy to share the information on How- To-Do-It (and possibly what not to do) here on Cloudy Nights.
Thank you gentlemen for the opportunity to jump in and add my two-cents worth.
Nick
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KennyJ
Reged: 04/27/03
Posts: 10082
Loc: Lancashire UK
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Hello again George.
I'm glad you got your 15 x 70s from SOMEWHERE ! -- but can hardly believe you couldn't find any available here in the UK . There are many retailers sell the Helios 15 x 70s like I have ,which are Japanese made BAK4 prisms , Fully -multi-coated and can be obtained for £139 new.
Trentmann still have a wide selection of BIG binos on their website too --but not to worry --enjoy your Oberwerks !
Regards --Kenny .
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Two eyes and a preference to use both
Zeiss 7 x 42 BGAT
Captain's Helmsman 7 x 50
Nikon 10 x 42 Superior E
Swift Audubon Kestrel 10 x 50
Helios 15 x 70 Observation
Strathspey 20 x 90
Televue 76 APO
Zeiss 85 Diascope
Helios 102 f5 refractor
Various eyepieces barlows tripods mounts etc.
Panasonic Lumix DMC - TZ5 digital camera
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Anonymous
Unregistered
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Thanks Kenny. I did try. Still i will be looking to purchase some 100mm binoculars soon. Any sujestions where in the U.K and recommended model. I'm still a newbie.
Also whats the opinion on the oberwerks 15 x 70 vs the higher priced Helios 15 x 70s? Would i have been better off purchasing the Helios rather than spending the extra money importing the oberwerks which could have been spent on the higher priced Helios. 
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KennyJ
Reged: 04/27/03
Posts: 10082
Loc: Lancashire UK
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George ,
Believe it or not - I have never actually looked through any of the variations of Oberwerk 15 x 70s , but from what I believe from our learned friend Ed Z -- the latest version which I think ( and hope )you must have got will probably be every bit as good as the Helios 15 x 70s with the little bonus of the slightly larger FOV of 4.3 degrees.
The stated FOV with the Helios is 4.0 degrees , but I calculate it to be more like 3.8 useable .
My main uses for binos ( and I own several pairs )are in fact terrestrial , but I do use them all for astronomy too.
My impressions of the Helios 15 x 70 ( as with ALL my binos )have suddenly been altered and quite dramatically elevated by about 20% now that I have finally got some eyeglasses to rectify my astigmatism .
I am very happy with them really for what they are -- but still prefer the wider fields of my Swift Kestrel 10 x 50 and Zeiss 7 x 42 and even the little Swarovski 8 x 20s are much better for astronomy than you might think.
As for availability and prices of 100mm binos in the UK I will make some updated enquiries and get back to you via this forum .
Until then -clear skies -- Kenny
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Two eyes and a preference to use both
Zeiss 7 x 42 BGAT
Captain's Helmsman 7 x 50
Nikon 10 x 42 Superior E
Swift Audubon Kestrel 10 x 50
Helios 15 x 70 Observation
Strathspey 20 x 90
Televue 76 APO
Zeiss 85 Diascope
Helios 102 f5 refractor
Various eyepieces barlows tripods mounts etc.
Panasonic Lumix DMC - TZ5 digital camera
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