Erik D
Carpal Tunnel
Reged: 04/28/03
Posts: 2713
Loc: Central New Jersey, USA
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The Burgess Optical Vireo 8X25 compact came up yesterday in a thread about stocking stuffer Binoculars. Shortly after I purchased a pair of BO Vireo 8X25 I became aware that WO offers a pair that's almost identical in apperance but are listed as semi APO, waterproof, and priced 43% higher. If you read this dealer web page you would think the only similarity between the WO and BO 8X25 is the apperance:
http://www.adorama.com/WO8X25.html?searchinfo=WO%208X25%20binocular&item_no=1
I like the wide 8.2 deg FOV, 3 ft close focus, O ring seal and nitrogen purged construction. Don't know what "Semi-apo Doublet Objectives" means. Calling 11mm ER "long eyerelief" is a stretch but should be OK for those who don't wear glasses. There is no mention of phase coating but everthing else looks pretty good.
Just wondering if anyone else has experience with or comments about this WO 8X25 1/2 APO?
Erik D
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Les
professor emeritus
Reged: 04/22/06
Posts: 677
Loc: Maryland
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Hi Eric,
I cringe every time WO uses the term "APO" since, when they use it, it signifies nothing more than the use of ED glass. This seems to be true of their telescope line as well. "Semi-APO"??? Probably another marketing term.
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Les
Canon 10x42L IS
Oberwerks BT80/45, Helix Hercules mount on Oberwerks Standard Tripod
Swift 8x44ED Ultralite
Questar 50th Anniversary Model, 501 head on Manfrotto 475 tripod
Stellarvue SV90T 90mm Fluorite refractor Bogen 3236/Televue Tele-Pod Head
Questar 7 Astro
Vixen GP-DX on Baader Surveyor Tripod
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Moggi1964
Carpal Tunnel
Reged: 11/07/05
Posts: 2515
Loc: Madison. NJ. USA
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Les,
I would be interested in knowing which defintion of apochromat you base that judgement on.
Thanks.
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Morris
WO Megrez 80 ED F/7
WO 8x42 binoculars
Seymor Rosin F/4.5 Astrograph in the making
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Les
professor emeritus
Reged: 04/22/06
Posts: 677
Loc: Maryland
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Quote:
I would be interested in knowing which defintion of apochromat you base that judgement on.
Certainly. "APO" = marketing term. "Apochromatic" = lacking any perceptible false color in the in focus image of bright stars, planets, and the Moon. Now there is a whole body of knowledge that describes how a DESIGN can achieve apochromatic performance which includes the number of color crossings which drive the use of exotic glasses, number of elements, etc. etc. What the marketing departments of many optics importers would have you believe is that, just because the DESIGN can support the creation of an apochromatic instrument (because it contains exotic glass), the instrument they deliver to your door will be apochromatic. Not necessarily so, because the manufacturing tolerances to achieve that design may be so extreme that you can not PRODUCE an apochromat at the price point that many of these APO scopes are being sold at. In other words, you cannot take lens elements at random from an assembly line and mount them in a cell and achieve the desired result without additional hand figuring or hand matching of elements whose individual errors tend to cancel each other. These steps drive the cost way up.
Many of the current crop of relatively inexpensive "APO" imports sold under various brand names do not achieve true apochromatic performance as documented in many reviews. Some have dropped their "APO" name and fallen back to "ED" which says more about the design than the manufacture.
Like Eric, I have no idea what Semi- Apochromatic Doublet means. And I have serious doubts about whether there are apochromatic binoculars with the possible exeption of long focal length binocular telescopes.
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Les
Canon 10x42L IS
Oberwerks BT80/45, Helix Hercules mount on Oberwerks Standard Tripod
Swift 8x44ED Ultralite
Questar 50th Anniversary Model, 501 head on Manfrotto 475 tripod
Stellarvue SV90T 90mm Fluorite refractor Bogen 3236/Televue Tele-Pod Head
Questar 7 Astro
Vixen GP-DX on Baader Surveyor Tripod
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Moggi1964
Carpal Tunnel
Reged: 11/07/05
Posts: 2515
Loc: Madison. NJ. USA
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I would suggest that until we have an agreed definition of what an apochromat is (and the Abbe one is well regarded but not completely clear in certain aspects according to Thomas Back) then no one is truly in a position to say who does and does not make an apochromat.
Thomas Back has this to say:
Link to Thomas Back piece on apochromats
So it seems TMB has been using the term semi-apo too!
I took issue with your response to Erick as you gave the impression in my mind that WO is the only company that is using these terms and in some way using marketing speak to dupe customers.
I have started a thread on the Refractors forum to try to understand the perspective of others; that's what I like about this site, it's where I learn.
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Morris
WO Megrez 80 ED F/7
WO 8x42 binoculars
Seymor Rosin F/4.5 Astrograph in the making
Edited by Moggi1964 (12/14/06 02:29 PM)
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EdZ
Professor EdZ
Reged: 02/15/02
Posts: 12792
Loc: Cumberland, R I , USA42N71.4W
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Les said:
Quote:
I have no idea what Semi- Apochromatic Doublet means.
Some very simple guidelines that can be found in a variety of publications, by some of the most highly regarded authors:
An achromat has a color spread of about 1/1800 to 1/2000th the focal length of the objective. That means the difference if focal length from red to blue will not vary by more than 1/2000th F.
An apochromat reduces that correction to 1/8,000th F.
A super apochromat reduces that correction to about 1/10,000 to 1/14,000th F.
A semi-apo has that correction at about 1/4,000th F.
The term semi-apo as defined above has been used in publications for at least 40 years.
Just a few other things to think about;
a poorly figured apochromat may produce images no better than a finely figured achromat.
I own a fine WO Megrez 80 SD II f/6.25 Semi-Apochromatic refractor. It is my 5th small refractor. It is far superior in color correction to any other achromat (from f/5 to f/11) I've owned. Only my TV85 Apo refractor surpasses it.
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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Rich N
Post Laureate
Reged: 09/22/04
Posts: 5351
Loc: San Francisco Bay Area, Calif...
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It's good Adorama listed the specs along with the list of features for this binocular because the specs list the eye relief as 11mm while the features say it is a long-eye relief design.
Rich
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Les
professor emeritus
Reged: 04/22/06
Posts: 677
Loc: Maryland
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Quote:
Some very simple guidelines that can be found in a variety of publications, by some of the most highly regarded authors:
Yes I am aware that these guidelines have appeared in the optics literature. But unfortunately there is no "industry standard" for terms like semi-apo. Unless your optics come with a test report, you must use the basic test of whether there is perceivable color or not. My point is that many of the current crop of "APO" refractors are failing this test as we read in reviews of these instruments. I think this is in large part to marketing departments touting the DESIGN as apochromatic while the production/quality control departments can't deliver.
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Les
Canon 10x42L IS
Oberwerks BT80/45, Helix Hercules mount on Oberwerks Standard Tripod
Swift 8x44ED Ultralite
Questar 50th Anniversary Model, 501 head on Manfrotto 475 tripod
Stellarvue SV90T 90mm Fluorite refractor Bogen 3236/Televue Tele-Pod Head
Questar 7 Astro
Vixen GP-DX on Baader Surveyor Tripod
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Les
professor emeritus
Reged: 04/22/06
Posts: 677
Loc: Maryland
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Quote:
I took issue with your response to Erick as you gave the impression in my mind that WO is the only company that is using these terms and in some way using marketing speak to dupe customers.
No, there are others that come to mind. "Dupe" is your word not mine. I am merely trying to make the distinction between DESIGN and the final PRODUCT when it comes to apochromatic performance. The user/buyer should be concerned about the latter while the academic is concerned with the former. It takes a lot of "elbow grease" to make a true color free refractor, even if you start with a TMB design. Fortunately, Thomas has enough integrity to sell his designs to companies that can in fact consistently produce to the design.
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Les
Canon 10x42L IS
Oberwerks BT80/45, Helix Hercules mount on Oberwerks Standard Tripod
Swift 8x44ED Ultralite
Questar 50th Anniversary Model, 501 head on Manfrotto 475 tripod
Stellarvue SV90T 90mm Fluorite refractor Bogen 3236/Televue Tele-Pod Head
Questar 7 Astro
Vixen GP-DX on Baader Surveyor Tripod
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Moggi1964
Carpal Tunnel
Reged: 11/07/05
Posts: 2515
Loc: Madison. NJ. USA
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Quote:
Fortunately, Thomas has enough integrity to sell his designs to companies that can in fact consistently produce to the design.
Companies like:
http://www.williamoptics.com/prod_tel/FLT110silver/features0.htm
You seemed concerned with the former (DESIGN) in your response to Erick being as there have been many excellent reviews about the colour free performance of WO apochromats. Wouldn't it be in keeping with your view of what the buyer should be concerned with (PRODUCT) to have pointed him to available reviews rather than bringing design and your views on it into the equation?
I think it was fair to read "dupe" or something similar into your wording however you are correct to say it was my interpretation and I did say "...gave the impression in my mind ...."; others likely read it differently.
If astronomy shops were as widespread as Starbucks I guess it would be easy to pop in and try a set of WO semi apo binoculars but we know that sadly that isn't the case.
I have a pretty good feeling that if Erick was to call David at WO and explain his reservations David might well send him out a pair to try with a money back guarantee! I may be wrong but my experience so far with WO suggests I may be right.
Go on Erick; give them a call and let us know what happens. 
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Morris
WO Megrez 80 ED F/7
WO 8x42 binoculars
Seymor Rosin F/4.5 Astrograph in the making
Edited by Moggi1964 (12/14/06 07:00 PM)
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Moggi1964
Carpal Tunnel
Reged: 11/07/05
Posts: 2515
Loc: Madison. NJ. USA
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Erik,
I apologise if I hijacked the thread by the way. I got a bit carried away and left you out.
I hope you find a terrific set of binoculars that match your needs.
FYI I will be posting a review of the 8x42 WO apo triplet binoculars I just bought; probably not till the New Year as I bought them for the wife to use for birding as a christmas present
Best not touch them till after the 25th eh
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Morris
WO Megrez 80 ED F/7
WO 8x42 binoculars
Seymor Rosin F/4.5 Astrograph in the making
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Les
professor emeritus
Reged: 04/22/06
Posts: 677
Loc: Maryland
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Quote:
there have been many excellent reviews about the colour free performance of WO apochromats.
Sorry for indicting the premium tier of the WO lineup. My venting was directed at their lower tier "APOs" which they share in common with many other importers. I don't recall reading any review of these that did not indicate some residual color on bright objects which was usually excused by the low price of the scope. It's either apochromatic (free of perceptable color) or it's not. ED glass may be a necessary condition for producing an apochromat but it is not a sufficient condition. Hence my understanding that APO has really become a marketing term. And what are we to make of the term Semi-APO. I know I will see some color (by definition) but how much? Without an individual test report, how do I know that my unit meets the "technical" definition of a Semi-APO design as quoted by EdZ. There are also attempts by importers (as I have seen discussed on other forums)to label some of these scopes as fluorite APOs when in fact they do not contain the mineral crystal fluorite as a lens element. There is a tremendous amount of hype surrounding these small aperture refractor offerings. I hate to see it spill into the binocular field as well.
Quote:
I have a pretty good feeling that if Erick was to call David at WO and explain his reservations David might well send him out a pair to try with a money back guarantee!
That would be the best of all possible worlds. And their definition of Semi-APO would be of interest too.
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Les
Canon 10x42L IS
Oberwerks BT80/45, Helix Hercules mount on Oberwerks Standard Tripod
Swift 8x44ED Ultralite
Questar 50th Anniversary Model, 501 head on Manfrotto 475 tripod
Stellarvue SV90T 90mm Fluorite refractor Bogen 3236/Televue Tele-Pod Head
Questar 7 Astro
Vixen GP-DX on Baader Surveyor Tripod
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Moggi1964
Carpal Tunnel
Reged: 11/07/05
Posts: 2515
Loc: Madison. NJ. USA
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Les,
I actually emailed WO in Taiwan to ask them about the definition proposed by TMB and how their scopes fit with it. If they don't fit with it then i asked them to define THEIR definition of an apochromat.
I will post any response I get (I haven't dealt with Taiwan before so if they don't get back to me I will contact David and see if he knows).
I am familiar with the flourite debacle and I know that WO had to eat humble pie from what I read.
Here are a couple of links to reviews where no false colour was seen on the small WO apo I use and its larger brother:
http://www.cloudynights.com/item.php?item_id=1471
http://www.astromart.com/articles/article.asp?article_id=215
http://www.astromart.com/articles/article.asp?article_id=363
Here's one for the 80 flourite (or not):
http://www.astromart.com/articles/article.asp?article_id=248
I am sure that a Borg or Takahashi would perform better to some extent but I figure these reviews are good examples of what the buyer with a $1000 or less to spend can get; excellent value for money in my opinion.
The 'what is an apo' debate over in Refractors has reached what is likely a common impasse (there is no hard and true definition so why discuss it) and I suspect we reached the same here.
Thanks for getting back to me Les on my original question and, more importantly, I hope Erik found something in here to help in his decision making.
Kind regards
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Morris
WO Megrez 80 ED F/7
WO 8x42 binoculars
Seymor Rosin F/4.5 Astrograph in the making
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EdZ
Professor EdZ
Reged: 02/15/02
Posts: 12792
Loc: Cumberland, R I , USA42N71.4W
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This Burgess/WO 8x25 has the same appearance as the UO model series shown
Hunting / Biring Series
BW9 series of Hunting Birding
Adorama Ad for WO 8x25
Highpoint Ad for Burgess 8x25
edz
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Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21
Edited by EdZ (12/15/06 06:01 AM)
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Les
professor emeritus
Reged: 04/22/06
Posts: 677
Loc: Maryland
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Quote:
I am familiar with the flourite debacle and I know that WO had to eat humble pie from what I read.
...and then there was the fully multicoated objective that was missing a coating in their first offering reviewed by S&T.
For the most part, the refractor fabricators/distributers refuse to represent to the buyer a specification in terms of fractional parts of focal length for color control. So, although these definitions exist in the optics literature, they are of little consequence in the marketplace. I think Vic Maris of Stellarvue gave a good answer (in the Stellarvue Yahoo group) as to why this is. To paraphrase: He cannot in all good honesty specify to the customer the amount of color correction achieved without actually testing AND QUANTIFYING the correction of each one as they go out the door. That would consume so much time as to raise the price point of the offering and lower the number of scopes delivered to where he could hardly turn a profit. Seems like a reasonble answer to me.
Excuse my venting about APO/Semi-APO terms. How about APO and APO-ish  Having watched the chaos created in the telescope world by their use, I hate to see it repeated in the binocular world.
Looking forward to your review of your APO triplet. Most interested to hear what you see when viewing the lunar rim.
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Les
Canon 10x42L IS
Oberwerks BT80/45, Helix Hercules mount on Oberwerks Standard Tripod
Swift 8x44ED Ultralite
Questar 50th Anniversary Model, 501 head on Manfrotto 475 tripod
Stellarvue SV90T 90mm Fluorite refractor Bogen 3236/Televue Tele-Pod Head
Questar 7 Astro
Vixen GP-DX on Baader Surveyor Tripod
Edited by Les (12/15/06 01:15 PM)
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EdZ
Professor EdZ
Reged: 02/15/02
Posts: 12792
Loc: Cumberland, R I , USA42N71.4W
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we've had enough of this, thank you.
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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