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Equipment Discussions >> Binoculars

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CuriousOne
member


Reged: 01/22/13

Need advice on mechanical quality of zoom binos
      #5636235 - 01/22/13 04:56 AM

Hello.

I found your forum very interesting and got answers to lot of questions while reading. However, there are still some aspects on which I need your advice.

I want some large binoculars with power zoom. I will mainly use it for wildlife observation during daylight, and ocasionally for sky viewing. I perfectly understand what is exit pupil, front lens diameter, focal distance, multicoating, field of view and so on. In military, I was serving at borderline security, so there we had all kind of serious optics, with up to $100K price tags.

So, considering my practical observations and past experience, I came to conclusion, that I need something like 40x80 or even 60x80 binoculars. Unfortunately, such binoculars appear to be made only in zoom binocular department, so my choice is quite limited. Since this is just hobby, I'd prefer not to spend more than $200 for that. I understand perfectly that in this price range I should not expect anything serious, so, for start-up, I've purchased celestron Upclose G2 binoculars 10-30x50. Besides heavy chromatic abberations, it has another serious flaw. The piece, on which eyepieces are mounted, is made of very thin plastic, so even if you touch it slightly with your eye, it changes position and looses focus. Since I'm using it for terrestrial observation, even slight movement of eyepiece makes focus loose, so I need to constantly re-adjust the focus, which is very troublesome.

Unfortunately, these zoom ones aren't sold in local stores, so I depend on amazon/ebay/etc for such purchases.

So, I'd like to hear, whenever these giant large zoom, inexpensive binoculars from barska, celestron, bushnell and so on, suffer from the same issue? As I mentioned above, personally, I'd prefer fixed 40x80 binoculars, but was not able to find such one for my price range.

Thanks in advance,

Alex


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Mark9473
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Reged: 07/21/05

Loc: 51°N 4°E
Re: Need advice on mechanical quality of zoom binos new [Re: CuriousOne]
      #5636241 - 01/22/13 05:10 AM

There definitely are 40x80 binoculars that don't zoom (e.g. from Docter Optics), but like you said they're above your price range.

To be honest a $200 80mm zoom binocular is going to be a waste of money. Your best bet at getting close to your target, IMHO, is looking for a fixed 30x80 binocular. But my recommendation would be to save up for something better (a 70 or 80mm binocular telescope with interchangeable eyepieces) or think outside the box (a spotting scope with zoom eyepiece).


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CuriousOne
member


Reged: 01/22/13

Re: Need advice on mechanical quality of zoom binos new [Re: Mark9473]
      #5636246 - 01/22/13 05:18 AM

Actually, I already went that way, but I found later that dual-eyed view is much more comfortable.

I currently also own the following setup:

Camlink 15-45x50 spotting scope, to which I attached 1.7x tele zoom attachment from old Sony DSC-717 camera. It works quite nicely. Also, I have 1000mm/F10 reflex lens, for which I DIYed eyepiece holder, and using 12mm C mount CCTV camera lens as eyepiece. It also works fine, especially for observing the moon, when it is low on horison and located above distant mountains, in this case, mountains also do appear in view, and huuuge moon above them, very spacey and extra-terrestrial look it gives.


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Mark9473
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Re: Need advice on mechanical quality of zoom binos new [Re: CuriousOne]
      #5636256 - 01/22/13 05:45 AM

Then I think I would advise you to save up for something like the Oberwerk BT70 45°. It is angled at 45° which will work well also for daytime observation. Garrett has a very good BT70 90° also but it's a 90° model so not as convenient for daytime viewing.

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edwincjones
Close Enough
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Reged: 04/10/04

Re: Need advice on mechanical quality of zoom binos new [Re: CuriousOne]
      #5636260 - 01/22/13 05:49 AM

Vixen has/had a 125mm binocular with zoom eps, quality was good at around $3500US, but FOV narrow;
you could also get one of the Binocular-Telescopes with inter changeable EPs and use zoom EPs (but need click stops)

edj


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Tony Flanders
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Reged: 05/18/06

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Re: Need advice on mechanical quality of zoom binos new [Re: CuriousOne]
      #5636288 - 01/22/13 06:28 AM

Given your requirements, I'm reasonably sure that a conventional single-objective telescope equipped with a binoviewer is what you really need.

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dunk1947
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Reged: 08/11/12

Loc: Peterborough UK
Re: Need advice on mechanical quality of zoom binos new [Re: Tony Flanders]
      #5636304 - 01/22/13 06:51 AM

According to several reviews, a zoom binocular's collimation can subject to error because it's difficult to maintain throughout the zoom range - and they are difficult to recollimate and service - in fact some repairers will not offer to service them. Personally I'd steer clear of zoom binoculars - with the possible exception of the Docter 40x model with zoom eyepieces.

dunk


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CuriousOne
member


Reged: 01/22/13

Re: Need advice on mechanical quality of zoom binos new [Re: dunk1947]
      #5636306 - 01/22/13 07:03 AM

I've used binoviewers, not on telescope, but as night vision device. They do not provide that feel of volume which is provided by true binoculars.

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EdZ
Professor EdZ
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Reged: 02/15/02

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Re: Need advice on mechanical quality of zoom binos new [Re: CuriousOne]
      #5636320 - 01/22/13 07:17 AM

I would also recommend against zoom binoculars. Read th "Best Of" thread rregardingg zooms.

There are no good reasons to buy a zoom binocular.

edz


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CuriousOne
member


Reged: 01/22/13

Re: Need advice on mechanical quality of zoom binos new [Re: EdZ]
      #5636341 - 01/22/13 07:39 AM

I can buy zoom binocular, but add additional hardware, to make them fixed zoom, so remove any wobble and collimation problems, related to zoom mechanism.

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Mark9473
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Reged: 07/21/05

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Re: Need advice on mechanical quality of zoom binos new [Re: CuriousOne]
      #5636343 - 01/22/13 07:41 AM

Go ahead and prove us wrong then.

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CuriousOne
member


Reged: 01/22/13

Re: Need advice on mechanical quality of zoom binos new [Re: Mark9473]
      #5636347 - 01/22/13 07:46 AM

Well, that is just idea, I think technically it's possible. But sure, I'd prefer to waste less time and get better output.

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Jawaid I. Abbasi
Carpal Tunnel
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Re: Need advice on mechanical quality of zoom binos new [Re: CuriousOne]
      #5636366 - 01/22/13 08:13 AM

Zoom Binocular? 10000000000% not recommandad
Binoviewer with richfield scope (YES)
BT-70 Definatly YES


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CuriousOne
member


Reged: 01/22/13

Re: Need advice on mechanical quality of zoom binos new [Re: Jawaid I. Abbasi]
      #5636372 - 01/22/13 08:19 AM

Binoviewer excluded, if I wanted one eyed, I would stick with telescope. I'm doing mostly terrestrial observations, so binoculars are must.

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Jon Isaacs
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Re: Need advice on mechanical quality of zoom binos new [Re: CuriousOne]
      #5636431 - 01/22/13 09:04 AM

Quote:

Binoviewer excluded, if I wanted one eyed, I would stick with telescope. I'm doing mostly terrestrial observations, so binoculars are must.




I saw you had a small spotting scope as well as a reflex lens, what other telescopes do you have? Good views at higher powers require decent optics. The view though and inexpensive spotting scope or reflex lens is not going to be anywhere near as Sharp as a decent quality telescope.

The real issue here is the $200 budget. Good optics cost money and binoculars have many optical components, many opportunities to degrade the image. They also must be properly aligned, so robust mechanical construction is a necessity. Telescopes can be much simpler so a decent astronomical telescope can be more affordable.

Jon


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BillC
on a new path
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Re: Need advice on mechanical quality of zoom binos new [Re: CuriousOne]
      #5636475 - 01/22/13 09:26 AM

"10000000000% not recommended"

C'mon Jawaid; say what you really mean!

Welcome CuriousOne:

You have asked about the "mechanical quality of ZOOM binoculars."

THERE IS NONE!!! Yes, there are some who will give the old “What about the . . .” However, I’m not one to give Jack the Ripper a pass because he once helped a cripple across the street.

You have also received some very informative posts from some very informed observers. SO, to help you further if I can, I would like to SEE their years of practical observing experience and RAISE decades in the optical industry and repairing and collimating more binoculars than most bino executives have ever seen in a warehouse—including thousands of military units.

The following is from a monograph on binocular realities:

*****

12. ZOOM BINOCULARS AND OTHER CONCEPTS FROM HELL

There are many reasons to be even more aware of “ZOOM” binoculars! To the uninitiated the ability to “ZOOM” is a feature; to the serious observer they are anything but! For the most part, the zoom is made possible by the movement of an auxiliary system in the ocular (eyepiece) assembly of each telescope. The tubes move fore and aft along the optical axis by means of a small brass screw which passes through helical slots in the walls of the auxiliary tubes. When the zoom is operated, a series of spur gears move the screws to send the auxiliary lens systems back and forth.

As you may have guessed, there’s going to be a lot of lost motion. And, even if the lenses were flawlessly matched in curvatures, spacings, thicknesses and glass types, the lost motion in the zoom mechanism is usually bad enough (especially as the instrument begins to age) to degrade the image. Also, while the brain can compensate for small errors in collimation, it can’t compensate for differences in magnification. That means your binocular could be collimated exceptionally well and you still wouldn’t have a good image!

Another negative attribute of almost all zoom binoculars is that they produce smaller fields of view than their fixed-power counterparts at any given magnification. Some are so bad, one might get the impression he or she is looking through a pipe instead of an optical instrument!

Finally, the auxiliary systems that make zooming possible are seldom sufficiently blackened. This causes a scattering of light and a loss of contrast across the entire field of view. So, can I recommend a really good zoom binocular? All the really good ZOOM binoculars I know of are listed in the box below:

(small rectangular box)

And, if you still feel it would be great to have a zoom mechanism on your binocular, please stop to consider why three of the most respected manufacturers of binoculars (Zeiss, Leica and Swarovski) don’t have a zoom binocular in their line-up. NOTE: The Leica Duovid only appears to zoom between its two fixed powers. If a high-quality zoom ever comes to the market, Leica is likely to be the company responsible.

*****

Yes, the above has been posted several times. But then, the problem has been raised several times, too.

If you still want a zoom instrument, please go ahead; sadly, experience is a far better teacher than I will ever be.

That monograph addresses several other bino misconceptions and I would be happy to send it to you should you send me your personal email address—my computer is full of them.

Again, welcome to our little family of misfits who might—just after taking the dog out at 3 a.m. in 18 degree weather—have to check the Cloudy Nights account before returning to bed . . . GUILTY!

Cheers.

BillC


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CuriousOne
member


Reged: 01/22/13

Re: Need advice on mechanical quality of zoom binos new [Re: BillC]
      #5636691 - 01/22/13 11:31 AM

Thanks everyone for warm welcome and friendly hints. But, I'd like to return to question I asked in the first post.

The cheap binoculars have very poorly made focusing system. So I asked, whenever such problem exists in larger ones?

Regarding the zoom binoculars, as I said, I can "convert" them into fixed zoom ones, by mechanically fixing the zoom components in place, so no miszoom will occur.

As I'm aiming mainly for daylight observation, say 15x80 will be less usable for me, than say 25x60.


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Jawaid I. Abbasi
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Re: Need advice on mechanical quality of zoom binos new [Re: BillC]
      #5636716 - 01/22/13 11:45 AM

Just wanted him to away from zoom binocular because I had it one time and the views were dim, do not stay focus, feel like seeing through straws and lot of false colours. I gaveup after few weeks.
I should have bought a $4000.00 fixed zoom instead the sub-$100 binocular but did not have that kind of money.


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SMark
scholastic sledgehammer
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Loc: Atlanta, GA USA
Re: Need advice on mechanical quality of zoom binos new [Re: Jawaid I. Abbasi]
      #5636772 - 01/22/13 12:17 PM

It's doubtful that anyone here will ever recommend a zoom binocular to anyone. There are many years of experience behind this.

You are going to be limited to looking at low quality Chinese made binoculars for the most part. Just try searching Amazon and other websites for the requirements you desire.

The best advice for you is simply to use a source that will allow you unlimited returns, since you should expect any binocular meeting your requirements to have quality issues. Just keep trying until you get one that is acceptable to you.

And most of all...

GOOD LUCK!


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Andresin150
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Reged: 08/14/07

Loc: Bogotá - La Calera / Colombia
Re: Need advice on mechanical quality of zoom binos new [Re: CuriousOne]
      #5636799 - 01/22/13 12:30 PM

Why would you want to buy a low quality zoom and then invest in "convert" them? there are also low and mid quality fixed power binoculars of 30x80. Any of them should be better than a zoom, let alone a "converted" one...
Are you capable of professionally "convert" it? or you are just planning on gluing the mechanism with gorilla glue when you feel the magnification is what you want? Having looked trough 100K optics is different than having the skills for doing that job, and for sure, someone that have the skills to do that job probably think is a waste of money and time.
And, I'm really not sure of having seen a $200 good high magnification 80mm binocular... maybe a bit more saving would help..


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KennyJ
The British Flash
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Reged: 04/27/03

Loc: Lancashire UK
Re: Need advice on mechanical quality of zoom binos new [Re: SMark]
      #5636813 - 01/22/13 12:37 PM

CuriousOne,

You have already been given most of the advice you need, whch amounts to STAY CLEAR OF ZOOM BINOCULARS, and ESPECIALLY ones that provide maximum magnifications above 15x.

I've tried many, and they are ALL A COMPLETE WASTE OF MONEY!!

Even your idea to fix the magnification at a high setting is fraught with danger and probably doomed to disappointment.

For one thing, to do so would do nothing to change the fact that the resulting exit-pupil would be around 0.5mm.

Another thing is it would only provide an acceptable image if the two sides were PERFECTLY aligned ( which they almost certainly WON'T be)

A third proviso is that BOTH sides are set to EXACTLY THE SAME MAGNIFICATION ( see Bill C's wise words about mechanical construction )

Your only hope I can think of within your stated budget would be a fixed focus 30x80, but every one I've tried has been pretty terrible too.
Kenny


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Jae
Pooh-Bah
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Reged: 04/13/06

Loc: New England
Re: Need advice on mechanical quality of zoom binos new [Re: KennyJ]
      #5636867 - 01/22/13 01:00 PM

Probably off topic from original poster of large zooms but.....

I always heard that the one zoom exception is the 8-16x40 XL Nikon zoom. So when I checked one out, I personally found that it was certainly usable and sometimes convenient.

But it's costly and nowhere to be found....

Jae


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CuriousOne
member


Reged: 01/22/13

Re: Need advice on mechanical quality of zoom binos new [Re: KennyJ]
      #5636868 - 01/22/13 01:01 PM

As I already noted, I DON'T LIKE 30X80. I need at least 40X or 50X zoom. I have used giant fujinon 25x150 binoculars, they are nice, but zoom is not enough!

Regarding the "conversion" I have acces to precise lathe and milling machine, also own light duty 3 axis CNC milling machine which can work with aluminum, brass and other soft metals, so, doing custom parts is not that hard for me.


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CuriousOne
member


Reged: 01/22/13

Re: Need advice on mechanical quality of zoom binos new [Re: CuriousOne]
      #5636873 - 01/22/13 01:03 PM

Again, I'm looking into "zoom" category, since they offer 40X and larger zooms. I found no cheap binocular with fixed magnification like 40X or higher.

I don't need zoom function at all.

even simpler: "gimme cheap 40x60, 50x70, 60x80" and so on


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Andresin150
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Loc: Bogotá - La Calera / Colombia
Re: Need advice on mechanical quality of zoom binos new [Re: CuriousOne]
      #5636880 - 01/22/13 01:08 PM

As Bill C noted:
"If you still want a zoom instrument, please go ahead; sadly, experience is a far better teacher than I will ever be"
So go ahead, buy, convert and share with us your experience...


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Patrik Iver
professor emeritus


Reged: 07/29/03

Loc: Kaarina, Finland
Re: Need advice on mechanical quality of zoom binos new [Re: CuriousOne]
      #5636884 - 01/22/13 01:09 PM

Where in the world are you located? If we knew, we might come up with realistic and available options for you.

Quote:

As I'm aiming mainly for daylight observation, say 15x80 will be less usable for me, than say 25x60.




Are you OK with short eye relief and individual focus? A used Kronos 26x70 might work. It is a Russian porro prism binocular with lightweight construction and fairly decent optical and mechanical quality. Works at full aperture, as opposed to most cheap Chinese alternatives. 65 degrees apparent field.


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Patrik Iver
professor emeritus


Reged: 07/29/03

Loc: Kaarina, Finland
Re: Need advice on mechanical quality of zoom binos new [Re: CuriousOne]
      #5636898 - 01/22/13 01:16 PM

So by "zoom" you really mean "high magnification" and not "variable magnification".

I'm afraid the others posters are correct in saying that you can't find a really high magnification binocular in your price range. The high magnification would require large aperture for usable exit pupil sizes, and that raises the cost. Perhaps even more important is that the mechanical quality required to maintain collimation at high powers can't realistically be found/done at the price level you are considering.


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CuriousOne
member


Reged: 01/22/13

Re: Need advice on mechanical quality of zoom binos new [Re: Patrik Iver]
      #5636901 - 01/22/13 01:17 PM

I live in Georgia, not state of U.S., but a small country, between Russia and Turkey. Sure, we have old soviet stock available here, but it's price went so high in last decade, that it now costs same as Leupold or similar brands ! Like used 12x60 binoculars costing around $300.

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Patrik Iver
professor emeritus


Reged: 07/29/03

Loc: Kaarina, Finland
Re: Need advice on mechanical quality of zoom binos new [Re: CuriousOne]
      #5636905 - 01/22/13 01:21 PM

I have a feeling that much of the old Soviet stock might actually be of a higher quality and better design and execution than much of the less expensive Asian stuff that is cheaply and easily available.

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BillC
on a new path
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Reged: 06/04/04

Loc: Lake Stevens, WA, USA
Re: Need advice on mechanical quality of zoom binos new [Re: Andresin150]
      #5636915 - 01/22/13 01:30 PM

THANKS EVERYONE FOR WARM WELCOME AND FRIENDLY HINTS. BUT, I'D LIKE TO RETURN TO QUESTION I ASKED IN THE FIRST POST. THE CHEAP BINOCULARS HAVE VERY POORLY MADE FOCUSING SYSTEM. SO I ASKED, WHENEVER SUCH PROBLEM EXISTS IN LARGER ONES?

The silliness of owning zoom binoculars rises exponentially as the aperture increases. Thus, I doubt you will find large zooms made by any company that comes even close to being respectable. And, as KennyJ points out, the exit pupil will be tiny—very, very dim image, especially for “daytime observations.”

REGARDING THE ZOOM BINOCULARS, AS I SAID, I CAN "CONVERT" THEM INTO FIXED ZOOM ONES, BY MECHANICALLY FIXING THE ZOOM COMPONENTS IN PLACE, SO NO MISZOOM WILL OCCUR.

If you’re talented enough to do that, you should already have enough money to buy whatever you want. I’ve been in optics for four decades and, as a Chief Opticalman for the Navy, know how to use a lathe, milling machine and pencil sharpener. I also have a background in optical geekology. Because of that, I wouldn’t touch the project with a ten-foot pole. There are too many variables you don’t know about.

I know that some people actually DO have “simple solutions” to complicated problems. I also know this is not a situation in which the previous sentence applies.

Finally, I could see from your last post, that you think all those who have chimed in to help you are missing the point and, not being one to enjoy peeing up a rope or being mistaken for being negative without provocation, I will just keep my mouth shut for a while. I would recommend that before you get too deep into your project you read a few books on binoculars (zooms in binoculars are 2 magnitudes harder to deal with) and that when you finish, you let us know the results.

BillC

PS When I see you repeatedly speak of ZOOMS with “FIXED” powers, I am told we have somewhat of a language barrier. Zoom binocular are not FIXED power and Fixed power binos can’t ZOOM. Thus, have another chunk of text from that monograph.

*****
1. I WANT THE MOST POWERFUL BINOCULAR YOU’VE GOT!

It is unfortunate that most consumers tend to want “power” (magnification) in a binocular over all other considerations. They throw the word around as if it were of singular importance and a binocular of any size could render any power. And why not? The work of well-meaning, but ill-qualified, freelance writers have given them few meaningful tools for understanding the laws of physics on which binoculars work. Instead, the consumer is met with a constant bombardment of “8x40 means,” or “field of view means,” ad nauseum!

Last year, a co-worker asked me a half dozen times or more what “power” binocular he should buy for hunting. I tried to answer his questions thoroughly and thoughtfully; I got nowhere. He had been too inundated by advertising buzzwords.

Finally, he threw his hands up in front of his face, put finger and thumb of each hand together, then separated his hands by about a foot (mimicking the actions of drawing out a telescoping telescope) and said, “I want something that will let me see far.”
The following day I gave him copies of two of my articles from Sea and Dockside magazines. Then, after giving him three days to digest the material, I asked if they had helped. Again, he duplicated the finger and thumb telescope draw and said, “I want something that will really reach out there.” He hadn’t learned a thing!

I tried to explain that binoculars don’t “reach” anywhere; they simply magnify the image formed from the light that strikes the objective lens — that’s all. However, years of reading poorly-investigated articles and grossly misleading ads overpowered my puny attempt to help his understanding.

The fact is, while “power” is the most talked about feature of any binocular, one should never choose an instrument offering more power than is necessary to do the particular job for which it was selected.

When magnification is increased:

* image brightness is decreased, because available light is spread over a greater area,
* field of view is decreased, making objects harder to find and keep centered,
* problems from body tremors are increased; you may need a tripod,
* atmospheric disturbances are accentuated, and
* imperfections in the objective lenses and prisms are accentuated.

Every week, hundreds of new amateur astronomers buy department store telescopes, advertised as offering 600x (power)! Virtually toys, they usually come in boxes adorned with photographs of celestial objects that the instrument wouldn’t be capable of revealing, should they be on a dark mountaintop . . . with perfect weather! Considering that a good telescope will provide a useful maximum of 60 power per inch of aperture, most of these little units shouldn’t be used at more than 120-power — even on nights of “good seeing”! Like it or not, whether viewing Jupiter, a bird in flight or a deer in the brush, the atmosphere is part of our optical system. Even the Hale telescope on Mt. Palomar, with its 16.6-foot mirror, is rarely used at powers greater than 1000!


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CuriousOne
member


Reged: 01/22/13

Re: Need advice on mechanical quality of zoom binos new [Re: BillC]
      #5636932 - 01/22/13 01:40 PM

The old soviet stock suffers from bad storage/handling (fungus, dirt, scratches, etc.) and also from fact that, optical coating was not so popular in soviet union, actually it became widely available only late 80s, when relatively small amount of optics were produced.

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KennyJ
The British Flash
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Reged: 04/27/03

Loc: Lancashire UK
Re: Need advice on mechanical quality of zoom binos new [Re: Patrik Iver]
      #5636948 - 01/22/13 01:46 PM

CuriousOne,

Are you SURE you understand the optical realities and practical difficulties inevitably associated with designing and producing,for example a 60x binocular of acceptable quality?

Putting aside that to successfully do so would probably cost around TWENTY TIMES your stated budget of $US200, have you considered that a typical field of view would be around 0.75 degrees ?

Would that REALLY provide the kind of viewing experience you are hoping to enjoy ?

Kenny


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CuriousOne
member


Reged: 01/22/13

Re: Need advice on mechanical quality of zoom binos new [Re: KennyJ]
      #5636965 - 01/22/13 01:59 PM

I've been at optical glass manufacturing factory at once. I know how glass is made (kron, flint, borosilicate, etc), which kind of optical glass exist, how they "boil" it into large piece, then splice it with minimal tensile deformations and machine the lens then. I also know that optical glass manufacturing is still mainly non-automated process and largerly depends on skilled personnel. But I don't get how all this relates to my initial question, which was like that: "eyepiece is very flimsy on my 10-30x50. Is same, weak construction used on larger ones, say 20-120x80 ?"

For field of view, my targets may be couple of miles away, easilly compensating narrowness of FOV.


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hallelujah
Post Laureate
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Re: Need advice on mechanical quality of zoom binos new [Re: CuriousOne]
      #5636978 - 01/22/13 02:05 PM

Quote:

I found no cheap binocular with fixed magnification like 40X or higher.

even simpler: "gimme cheap 40x60, 50x70, 60x80" and so on




They do not exist.


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KennyJ
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Re: Need advice on mechanical quality of zoom binos new [Re: CuriousOne]
      #5636994 - 01/22/13 02:11 PM

The simple answer to that question is YES, as you ought to have realised if you read what Bill C. wrote in his first reply to you.

From many years experience of long distance daytime terrestrial viewing through spotting scopes ( 48 years to be precise ) I can assure you that a TFOV of 0.75 degrees does NOT often provide satisfying views of wildlife nor much of anything else for that matter.

Kenny


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SMark
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Re: Need advice on mechanical quality of zoom binos new [Re: hallelujah]
      #5637025 - 01/22/13 02:21 PM

I cannot say anything about the quality of this one, but at least it is something for you to consider...

15x to 45x


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Mark9473
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Re: Need advice on mechanical quality of zoom binos new [Re: KennyJ]
      #5637026 - 01/22/13 02:22 PM

There is no cheap but decent solution for the requirements that have been set, it's as simple as that. A BT70 is one option, a telescope with binoviewer is probably going to be even better as it can be had it larger aperture without excessive weight.

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CuriousOne
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Re: Need advice on mechanical quality of zoom binos new [Re: Mark9473]
      #5637047 - 01/22/13 02:32 PM

Ok. Understood. If zooms are trash, I won't use them.

Since I have two of these 1000mm/F10 reflex lenses, maybe there's some solution to join them together, to form a giant "binoculars?" I tried by using old porro prism binocular with front lens removed, only eyepieces and prisms in place, but distance between tubes was still large to fit on both lenses.


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SMark
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Re: Need advice on mechanical quality of zoom binos new [Re: SMark]
      #5637048 - 01/22/13 02:33 PM

Quote:

I cannot say anything about the quality of this one, but at least it is something for you to consider...

15x to 45x




However...

Also take a look at this one which seems to fit your requirements almost perfectly... And then go down to the bottom of the page and carefully read the 3 reviews of this particular binocular. That should give you an idea of exactly what you might expect from just about any similar binocular...

20-140x80


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BillC
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Re: Need advice on mechanical quality of zoom binos new [Re: Mark9473]
      #5637052 - 01/22/13 02:35 PM

"as you ought to have realised if you read what Bill C. wrote in his first reply to you."

Judging by the artful dance around ALL the experience that has been laid before him. I respectfully submit that our friend is not into reading, but rather, in getting questions that can't be answered . . . answered. It's like the guy who feels that with enough steel wool he can knit a Mercedes.

I'm feeling the ghost of the Curmudgeon coming on, so I'm outta here for a time.

BillC


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hallelujah
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Re: Need advice on mechanical quality of zoom binos new [Re: SMark]
      #5637063 - 01/22/13 02:40 PM

This was posted on the Oberwerk.com website.

Zoom Models Discontinued-
Oberwerk has stopped production of zoom binoculars.
We've decided that the optical performance problems unique to zoom binoculars make fixed-power and multi-ocular binoculars a much better choice.
For more information, please see the article "Just Say No to Zoom Binoculars".
The Oberwerk 10-30x60 and 12-36x70 models will be supported indefinitely.

http://www.bigbinoculars.com/nozooms.htm


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Mark9473
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Re: Need advice on mechanical quality of zoom binos new [Re: CuriousOne]
      #5637181 - 01/22/13 03:43 PM

Quote:

Since I have two of these 1000mm/F10 reflex lenses, maybe there's some solution to join them together, to form a giant "binoculars?" I tried by using old porro prism binocular with front lens removed, only eyepieces and prisms in place, but distance between tubes was still large to fit on both lenses.



That experiment is not without merit. I understand you're saying the diameter of the two reflex lenses is larger than the distance between the binocular's prisms. Could you give a bit more detail, such as measurements? There may be certain binoculars that lend themselves better to do this.

Understand that you'll have a whole lot of tinkering ahead of you to properly align the two optical trains to give a good image.

Did you experience any particular back focus or other problems? In other words, does it work fine with just one tube?

Another option you have along the same lines is to take a binocular and replace the objectives with longer focal length achromatic objectives. Same amount of tinkering (at least) but it will ultimately get you your 40x to 60x binocular.

I expect that along the way you'll learn that a binoviewer on a telescope is just going to be a whole lot easier. I'm still uncertain why you've dismissed this actually.


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Jon Isaacs
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Re: Need advice on mechanical quality of zoom binos new [Re: CuriousOne]
      #5637473 - 01/22/13 06:05 PM

Quote:

As I already noted, I DON'T LIKE 30X80. I need at least 40X or 50X zoom. I have used giant fujinon 25x150 binoculars, they are nice, but zoom is not enough!

Regarding the "conversion" I have acces to precise lathe and milling machine, also own light duty 3 axis CNC milling machine which can work with aluminum, brass and other soft metals, so, doing custom parts is not that hard for me.




How about the optics? At 50x, an 80 mm binocular objective is going to show significant chromatic aberration, the achromatic objectives are too fast, color fringing will be a big problem.

Since you have the capability to mafhine your own parts, I suggest building your own 80mm zoom binoculars. Ideally you would want two 80mm ED-80 objectives, a couple of used ED-80s would be about $600. Add a couple of diagonals and a couple of zoom eyepieces and you would be set Optically. An ED-80 is good up to over 100x during the day. If that puts you over budget, some Surplusshed achromats might suffice, 80mm f/11 are reasonably color free at 60x. It would make for very long binoculars.

Mechanically they could be of the staggered over and under design, this allows for the use of the simpler telescope optics which can be sharper.

Starting with the optics from an inexpensive pair of zoom binos is a losing strategy because the optics themselves are inherently flawed and not capable of delivering acceptable images at 50x under any circumstance.

Jon


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Jawaid I. Abbasi
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Re: Need advice on mechanical quality of zoom binos new [Re: Mark9473]
      #5637493 - 01/22/13 06:21 PM

Send an email to "PAUL RANI" or "BILL" if you want to experiment and wanted to build 4" objectives for binocular purpose.

It will be fun and certainly give you experiance building the Binocular according by your needs.

Check the "OBERWECK" website for 3-axis alignment. Doing experiment is no harm.

Lastly, As "MARK" mentioned the 70mm binocular is the best option. I used my APM-100 Binocular telescope sometime at 60x and the views were not bad at all.

Buying "BAADAR ZOOM" and and "inter-changeable Binocular Telescope" will be the best solution.


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KennyJ
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Re: Need advice on mechanical quality of zoom binos new [Re: Jon Isaacs]
      #5637535 - 01/22/13 06:50 PM

Jon made some great points there.

However, on what may be considered a cautionary note,so far as "good for 100x during the day" goes, what I've found is that magnifications of around 100x can be tremendously exciting and awe-inspiring, but almost always ONLY when viewing objects that are located less than 100 yards away in the first place.Beyond that,atmospheric effects all too often come into the equation.

In an effort to further satisfy a lifelong lust for long distance daytime terrestrial viewing,for several years I owned one of the most expensive 85mm spotting scopes ever made.Yes,it was Zeiss.

Alas,even through that,the images could never compete with those through my TeleVue 76mm APO, due mainly to the presence of PRISMS.

Even through the amazing little TeleVue, very rarely indeed are atmospheric conditions so optics-friendly that magnifications in excess of 40x provide any real advantages over 40x itself.

Ground and/or higher air mist,mirage or heat-haze,even when unseen by naked eye, are magnified proportionately to magnification,and it interferes annoyingly with the level of detail the viewer hopes and wishes to see at those more exciting magnifications.

Lowering the magnification not only increases one basic ingredient essential for a satisfying viewing experience,BRIGHTNESS,but through any zoom lens or "like for like" fixed focal length eyepiece, considerably increases the field of view, which I consider even more important for daytime observing than for night-time sky viewing.

People wouldn't happily pay six or seven times more for a 100 degree AFOV eyepiece than they need to for an excellent 50 degree AFOV eyepiece if they didn't consider it worth the considerable extra cost.

Some of these eyepieces alone cost far more than the original poster is apparently prepared to pay for the entire instrument.

Kenny


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GlennLeDrew
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Re: Need advice on mechanical quality of zoom binos new [Re: KennyJ]
      #5637583 - 01/22/13 07:21 PM

Getting 40-50X out of a $200 binocular is not going to happen, if you want a view that's better than seen through a couple of jam jar bottoms.

Far better to adapt a couple of telescope objectives to a binocular body. For example, say you start with an existing 12X50. Such a bino has objectives of about 190mm focal length. Objectives having a focal length 4X longer, i.e., 760mm, will deliver 12 * 4 = 48X. Inexpensive achromatic objectives of 80-100mm diameter having a focal length of 600-700mm should be easy to locate. Surplus Shed is a good first source to check out.


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edwincjones
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Re: Need advice on mechanical quality of zoom binos new [Re: GlennLeDrew]
      #5637612 - 01/22/13 07:43 PM

I have a pair of zeiss 10+15x50s, a great binocular
but
not really a zoom, as has 10x, 15x, with effort can get something inbetween;
but heavy, expensive, not very popular to many

I used the vixen 25-75x125 once at a star party, but FOV was very small and seemed more like a binoviewer view
but it was a quality instrument

there is a 30-50x80 Doctor also

so it is possible but not cheap, with many compromises

edj


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Jon Isaacs
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Re: Need advice on mechanical quality of zoom binos new [Re: KennyJ]
      #5637647 - 01/22/13 08:09 PM Attachment (15 downloads)

Quote:


However, on what may be considered a cautionary note,so far as "good for 100x during the day" goes, what I've found is that magnifications of around 100x can be tremendously exciting and awe-inspiring, but almost always ONLY when viewing objects that are located less than 100 yards away in the first place.Beyond that,atmospheric effects all too often come into the equation.




Kenny:

I agree with you, a clear view at 100x a quarter mile away is pretty rare. It does happen, most often when viewing across a body of water.

Jon


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BillC
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Re: Need advice on mechanical quality of zoom binos new [Re: Jon Isaacs]
      #5637693 - 01/22/13 08:38 PM

BIG DEAL! Look at his nails; I can't tell if he's using Clinique or Loncome!

BillC


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CuriousOne
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Re: Need advice on mechanical quality of zoom binos new [Re: BillC]
      #5638029 - 01/22/13 11:40 PM

Is this website real?

http://www.fitsmybudget.com/OpSwiss-15-45x80-Zoom-High-Resolution-Binoculars-...

Price of these opswiss binoculars is exactly half of the price on amazon!


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SMark
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Re: Need advice on mechanical quality of zoom binos new [Re: CuriousOne]
      #5638065 - 01/22/13 11:59 PM

Quote:

Is this website real?

http://www.fitsmybudget.com/OpSwiss-15-45x80-Zoom-High-Resolution-Binoculars-...


Price of these opswiss binoculars is exactly half of the price on amazon!




Well... A cheap Chinese binocular is in fact... a cheap Chinese binocular.


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CuriousOne
member


Reged: 01/22/13

Re: Need advice on mechanical quality of zoom binos new [Re: SMark]
      #5638105 - 01/23/13 12:28 AM

Side question:

Will this:

http://www.ebay.com/itm/Tasco-1-25-ZOOM-telescope-ERECTING-eyepiece-8-to-18MM...

fit into this:

http://www.ebay.com/itm/Meade-1-25-refractor-telescope-eyepiece-focuser-NEW-/...

?


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BillC
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Re: Need advice on mechanical quality of zoom binos new [Re: CuriousOne]
      #5638383 - 01/23/13 08:16 AM

yes.

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Jon Isaacs
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Re: Need advice on mechanical quality of zoom binos new [Re: BillC]
      #5638597 - 01/23/13 10:27 AM

Quote:

yes.




I think a more complete answer is required.

Yes, but....

Jon


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CuriousOne
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Re: Need advice on mechanical quality of zoom binos new [Re: BillC]
      #5638630 - 01/23/13 10:42 AM

Thanks.

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Rich V.
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Re: Need advice on mechanical quality of zoom binos new [Re: CuriousOne]
      #5638639 - 01/23/13 10:47 AM

To create an erect image without prisms would require an eyepiece with a positive/negative Galilean design, I suppose. I can only imagine the "peep hole" view this Tasco 8-18mm zoom would provide. Not highly recommended.

Rich


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planetmalc
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Re: Need advice on mechanical quality of zoom binos new [Re: CuriousOne]
      #5638657 - 01/23/13 10:56 AM

Quote:

Ok. Understood. If zooms are trash, I won't use them.

Since I have two of these 1000mm/F10 reflex lenses, maybe there's some solution to join them together, to form a giant "binoculars?" I tried by using old porro prism binocular with front lens removed, only eyepieces and prisms in place, but distance between tubes was still large to fit on both lenses.




This is possible as long as the mirror lenses can be close-focused; this will bring the focal plane out far enough to use a suitable binocular with the objectives removed. As you've already discovered though, finding a binocular with widely-spaced objectives is not easy, and it would also have to be of very high quality because you might end up with an instrument working at about 50x magnification, which could be around 5 times greater than the binocular manufacturer had ever anticipated. Additionally, I seem to recall that photographic lenses have a slightly different colour correction when compared with optics that are designed for purely visual use (it's all to do with the colour bias of film stock, which differs from that of the eye).


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CuriousOne
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Re: Need advice on mechanical quality of zoom binos new [Re: planetmalc]
      #5638720 - 01/23/13 11:24 AM

Regarding binoculars, I have one, high quality soviet binocular, 12X60, which is wide enough to fit these two lenses together, but one of it's prisms is broken, so no much use.

Another question regarding these lens. As I know, the zoom ratio is determined by "length" of objective / "length" of eyepiece. So, say I have 1000mm objective (F10 power) and 10mm eyepiece (F1.8). Zoom will be 100x as I know, but what will be the effective F number?


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Tony Flanders
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Re: Need advice on mechanical quality of zoom binos new [Re: Rich V.]
      #5638797 - 01/23/13 12:05 PM

Quote:

To create an erect image without prisms would require an eyepiece with a positive/negative Galilean design, I suppose.




Not necessarily. You can make an image erector with lenses by bringing the light to a second focus.


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planetmalc
sage


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Re: Need advice on mechanical quality of zoom binos new [Re: CuriousOne]
      #5638833 - 01/23/13 12:29 PM

Quote:

Another question regarding these lens. As I know, the zoom ratio is determined by "length" of objective / "length" of eyepiece. So, say I have 1000mm objective (F10 power) and 10mm eyepiece (F1.8). Zoom will be 100x as I know, but what will be the effective F number?




You may be having a language-translation problem: what you are referring to as 'zoom' is what we'd call 'magnification'. In the example above, your magnification would be 100x, your F number would still be 10, and your exit pupil would be 1mm. There WOULD be an 'effective focal ratio' if you were using the combination photographically, but you don't need to consider this if you're using it visually.

Any instrument with a 1mm exit pupil would give dim images on terrestrial subjects and would not make for comfortable viewing when used at night (over lengthy periods of time, anyway). It would, however, be great for the Moon and the brighter planets.

Edited by planetmalc (01/23/13 12:34 PM)


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BillC
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Re: Need advice on mechanical quality of zoom binos new [Re: Jon Isaacs]
      #5638887 - 01/23/13 12:58 PM

Quote:

Quote:

yes.




I think a more complete answer is required.

Yes, but....

Jon




A 1.25-inch EP is made to fit a 1.25-inch focuser. Short or long the answer is still "yes." CuriousOne said nothing about vignetting, aberrations or overall quality.

BillC


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CuriousOne
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Re: Need advice on mechanical quality of zoom binos new [Re: planetmalc]
      #5638893 - 01/23/13 01:00 PM

Thanks, how size of exit pupil was calculated in that case?

1000mm/10mm/F10 ? but still 10, not 1 ?


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Mark9473
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Re: Need advice on mechanical quality of zoom binos new [Re: CuriousOne]
      #5638897 - 01/23/13 01:01 PM

exit pupil = entrance pupil (lens diameter) divided by magnification.

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CuriousOne
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Re: Need advice on mechanical quality of zoom binos new [Re: Mark9473]
      #5638907 - 01/23/13 01:08 PM

Ok, so considering my previous experience with binoculars, where I found exit pupil of 2-3mm quite acceptable for my purposes, this means, that if using that 1000mm lens, I should target 30-50 magnification range, which itself translated to eyepiece mm, means that I need eyepiece with 20-33mm range, right?

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Mark9473
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Re: Need advice on mechanical quality of zoom binos new [Re: CuriousOne]
      #5638962 - 01/23/13 01:41 PM

Exactly! I'm happy you're coming to that conclusion. Not much fun in daytime viewing below an exit pupil of about 2 mm in my experience too.

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CuriousOne
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Re: Need advice on mechanical quality of zoom binos new [Re: Mark9473]
      #5638982 - 01/23/13 01:57 PM

Ok, here's another question.

I have medium format camera lens 150mm/F2.8. It's front element is 82mm in diameter. Say I want 30x magnification. This will give me 82/30=2.7mm, which is fine. Considering the zoom needed, eyepiece should be 150/30=5mm.

OK

Now, above mentioned 1000mm lens can provide same exit pupil at 100/2.77=36x magnification. Not that much difference, right?

So, regarding the image, in which case from above mentioned, it will be brighter? if this was a photography question, I definetly know that F2.8 lens provides much much brighter image than F10 lens. But, in astronomy, where pupil matters, F number has no use?


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Patrik Iver
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Re: Need advice on mechanical quality of zoom binos new [Re: CuriousOne]
      #5639048 - 01/23/13 02:52 PM

Quote:

Since I have two of these 1000mm/F10 reflex lenses, maybe there's some solution to join them together, to form a giant "binoculars?"




These are Maksutov-type, right?

Then they are probably focused by adjusting the distance between the meniscus/secondary and the primary mirror. To get the focal plane pushed far enough back through the porro prism cluster for you to reach the eyepiece focal plane (thus reaching infinity focus) might be difficult using the standard tele-lens body, as the focal plane in a camera is pretty close to the lens rear port, and they probably never were designed to focus that far back. And even assuming it can be done, I think you might get some other aberrations from locating the meniscus/secondary closer to the primary than originally intended, plus the effective focal length will increase (giving higher magnification) and the effective aperture might decrease.

Still, an interesting concept to experiment with, but I pessimistically predict that reaching and maintaining collimation will be mechanically very challenging.

Being a pessimist means you rarely get disapponted, and when you are proven wrong, you get pleasantly surprised! Win-win


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CuriousOne
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Re: Need advice on mechanical quality of zoom binos new [Re: Patrik Iver]
      #5639067 - 01/23/13 03:10 PM

Yes, these are Maksutov type. Model is MC MTO 11: http://lzos.ru/en/index.php?page=shop.product_details&flypage=shop.flypag...

Focus is done via rotating the parts against each other, which itself changes the distance between them. Interesting, they do not have "infinity" focus, for example, after I focus on moon, I still have about half of a turn to rotate. It was designed for deep space exploration?

In soviet times, focuser/eyepiece attachments were manufactured and sold for this lens, but they are almost impossible to get now.


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Mark9473
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Re: Need advice on mechanical quality of zoom binos new [Re: CuriousOne]
      #5639151 - 01/23/13 04:04 PM

Quote:

So, regarding the image, in which case from above mentioned, it will be brighter? if this was a photography question, I definetly know that F2.8 lens provides much much brighter image than F10 lens. But, in astronomy, where pupil matters, F number has no use?




That's correct. The focal ratio only determines the focal length and therefore the magnification. For questions about brightness, specifically for daytime use, exit pupil is what you need to look at. For nighttime use, when it comes to point sources (stars) it is the aperture that matters; the exit pupil will then determine the brightness of the sky background and the very diffuse nebulous objects.


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BillC
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Re: Need advice on mechanical quality of zoom binos new [Re: Mark9473]
      #5639466 - 01/23/13 07:35 PM

“I have medium format camera lens 150mm/F2.8. It's front element is 82mm in diameter. Say I want 30x magnification. This will give me 82/30=2.7mm, which is fine. Considering the zoom needed, eyepiece should be 150/30=5mm.”

Curious:

When I read phrases like “Considering the zoom needed . . .,” I am left to believe you still don’t understand what “zoom” connotates in the world of optics. If I am correct, it is going to be difficult to impossible to answer some of your questions accurately—at least without covering the same topic again and again. Reading between the lines for your meaning, I think you would do well to forget the term “zoom” exists.

Because of my often too matter of fact mannerisms, I am frequently thought to be harsh when I have no such intention. So PLEASE take what I am about to say as just an old fool trying to be helpful.

Phrases like “A stitch in time saves nine” (popular, but not totally original structure) and “Don’t put the cart before of the horse,” came to be out of necessity and they seem germane to where this thread has gone . . . at light speed. And, while getting many very good responses, I don’t believe you are at the point of putting it all together, just yet. This is NO reflection on any language barrier or issue of aptitude, as you appear quite bright. It is, instead, an issue of general optics knowledge.

Newton or Leibniz could have the total attention of a 9-year old for an hour without having the youngster grasp the simplest point of calculus (You can substitute “BillC” for “9-year old,” if you want; I was just trying to save face.)

And, again, there are things with which only we opto-twidgits are going to be familiar.
For example: in GENERAL TERMS, 1000mm lens in camera talk refers to FOCAL LENGTH. Telescope makers might speak of a 1000mm objective in terms of DIAMETER.

EdZ and Glenn know the math you need and, if required, Stan could pull up a link for the best method of cleaning a rusty grill using banana oil in about .08 seconds. Ask those guys to send you some downloads pertinent to your questions. And, don’t forget the PDF I offered you.

Then, get a bowl of popcorn, a Coke, a highlighting marker and tell your wife, “Not tonight dear; I have a headache.” Then, get in bed with a good bedside lamp and read away!

There no shame in reading; I kept optics books by my bedside for 30 years . . . they make great coasters.

Go over the material, and over the material and over the material, until it becomes part of you. As you do, you will find that answers to your questions will become more understandable. Heck, with enough reading, you might even be able to understand KennyJ. Hey . . . it could happen!

Cheers,

BillC


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GlennLeDrew
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Re: Need advice on mechanical quality of zoom binos new [Re: BillC]
      #5639539 - 01/23/13 08:39 PM

Just to clarify. A 150mm focal length f/2.8 imaging lens has an actual working aperture of 150 / 2.8 = 53mm. The clear aperture of 83mm is only to allow off-axis light to get through to the image plane without suffering too much vignetting. And the reason for this larger aperture is because the front element is located some not insignificant distance in front of the lens's iris, or entrance pupil, which is also known as the nodal point.

And as you seem to have divined already, an imaging objective and an afocal system are quite different items. For direct imaging, an objective's focal ratio directly controls image surface brightness at the focus. An afocal system (e.g., a telescope) sends parallel light exiting the eyepiece into the eye, which the latter focuses on the retina. And so image surface brightness is controlled by the exit pupil, or the eye's own pupil, whichever is the smaller.

As BillC has pointed out, it must be asked... When you use the word "zoom", do you mean higher magnification (fixed, but 'zoomed in', so to speak), or instead a variable magnification (where you can smoothly zoom in and out over some range)?


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CuriousOne
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Re: Need advice on mechanical quality of zoom binos new [Re: GlennLeDrew]
      #5639737 - 01/23/13 10:57 PM

Well, that was my fault, yes, I used "zoom" where I should used "magnification".

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planetmalc
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Re: Need advice on mechanical quality of zoom binos new [Re: CuriousOne]
      #5640385 - 01/24/13 10:41 AM

If you are serious about the idea of using your two Maksutovs to make a large binocular, you need to: close-focus the lens to its limit; form an image of a DISTANT object onto a screen; measure the distance between the screen and the end of the focuser; then let us know what this distance is so that we can tell you whether or not your scheme is feasible.

Edited by planetmalc (01/24/13 10:48 AM)


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Rich V.
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Re: Need advice on mechanical quality of zoom binos new [Re: planetmalc]
      #5640421 - 01/24/13 10:56 AM

How does one propose getting a proper interpupillary distance with two 100+mm diameter optics if these Maks are used? Do they have enough back focus for prism assys to be incorporated? Did I miss something here?

Rich


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planetmalc
sage


Reged: 10/21/09

Re: Need advice on mechanical quality of zoom binos new [Re: Rich V.]
      #5640429 - 01/24/13 10:59 AM

This is what we're trying to determine, Rich.

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BillC
on a new path
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Re: Need advice on mechanical quality of zoom binos new [Re: planetmalc]
      #5640458 - 01/24/13 11:17 AM

Quote:

This is what we're trying to determine, Rich.




Understood. However, just as it easier to make a 6-inch mirror AND a 12.5-inch mirror than a 12.5-inch mirror alone, it will be easier for CuriousOne to make better decisions and ask more pointed questions by taking some time off to read a little on optical realities. Stuffy or not, without doing so, this thread will grow to be 10 pages in 4 more days and CuriousOne will know little more than he does now. But, I have approached that logic several times to no avail, so I will stop recommending it.

Cheers,

BillC


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Rich V.
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Re: Need advice on mechanical quality of zoom binos new [Re: BillC]
      #5640521 - 01/24/13 11:54 AM

It just seems to me that an inexpensive 30x80 bino will provide all the reasonable magnification that can be had for terrestrial use. More magnification at long distances more often than not just doesn't cut it due to surface atmospheric disturbance which has already been discussed here. A 30x80 provides a usable ~2.5mm exit pupil with a usable focusing mechanism and IPD adjustment incorporated into a handy package. Hard to beat, IMO.

For me, even my higher quality 22x binos show too much air turbulence at long distances under many circumstances.

This query seems to be headed to a lot of trouble for little realized good.

Just my opinion, of course...

Rich


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Mark9473
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Re: Need advice on mechanical quality of zoom binos new [Re: Rich V.]
      #5640551 - 01/24/13 12:17 PM

Quote:

How does one propose getting a proper interpupillary distance with two 100+mm diameter optics if these Maks are used? Do they have enough back focus for prism assys to be incorporated? Did I miss something here?



The idea was to mount a porro binocular body with the objective barrels removed, behind the two lenses. He tried with one binocular but that wasn't wide enough. He had another one that was wide enough, but that was defective on one side.


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CuriousOne
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Re: Need advice on mechanical quality of zoom binos new [Re: Mark9473]
      #5643813 - 01/26/13 05:22 AM

Say the 3 fold calendar, like this:

https://sites.google.com/site/giffitti/3FOLDSHIPPINGCALENDAR.jpg

is hang about 180 meters away and binoculars allow to distinguish and read smallest text ("week") on them. Such binoculars are considered good or bad?


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EdZ
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Re: Need advice on mechanical quality of zoom binos new [Re: CuriousOne]
      #5644070 - 01/26/13 10:01 AM

Quote:

Say the 3 fold calendar, like this:

https://sites.google.com/site/giffitti/3FOLDSHIPPINGCALENDAR.jpg

is hang about 180 meters away and binoculars allow to distinguish and read smallest text ("week") on them. Such binoculars are considered good or bad?




without knowing the actual size of the letters and the power at which the binocular is used, this question, which really measures only one aspect, resolution, cannot be answered. Even if yyoou knew alll the above and were abble to ansswer the question, theres's at leastt anotheer 10 aspets of performaancce to measure to determine if ythe binocular is good or bad.


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planetmalc
sage


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Re: Need advice on mechanical quality of zoom binos new [Re: EdZ]
      #5644306 - 01/26/13 12:21 PM

Instruments like this HAVE been produced commercially: I went to the London Astronomy Show a few years ago and one of the Russian companies - Intes, maybe - had produced a pair of 6" Maksutovs with Porro 1 prism/eyepiece units for in-line viewing. They gave a very sharp image.

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CuriousOne
member


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Re: Need advice on mechanical quality of zoom binos new [Re: EdZ]
      #5644332 - 01/26/13 12:42 PM

Actual size is about 20mm x 6mm.

Power unknown, since this is homemade binocular.


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EdZ
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Re: Need advice on mechanical quality of zoom binos new [Re: CuriousOne]
      #5644516 - 01/26/13 02:35 PM

Quote:

Actual size is about 20mm x 6mm.

Power unknown, since this is homemade binocular.




Which letter the W?

that would be appropriate for testing a 10x to 12x binocular at that distance. Any higher magnification than that and those letters would not be small enough to test the resolution of the poweer being used.

edz


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Simon S
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Re: Need advice on mechanical quality of zoom binos new [Re: EdZ]
      #5644640 - 01/26/13 03:55 PM

You will find none of the High end binocular manufacturers selling zoom binoculars, although Nikon ans a few others do sell a zoom to cater for public demand.

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SMark
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Re: Need advice on mechanical quality of zoom binos new [Re: Simon S]
      #5644992 - 01/26/13 07:41 PM

Quote:

You will find none of the High end binocular manufacturers selling zoom binoculars, although Nikon ans a few others do sell a zoom to cater for public demand.




Has anyone here actually tried either of the Nikon Action Zooms?


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GlennLeDrew
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Re: Need advice on mechanical quality of zoom binos new [Re: SMark]
      #5645076 - 01/26/13 08:25 PM

Fellas,
It's been established already that the word 'zoom' in the title actually should have been 'high magnification'. What we know of as a zoom bino is not what is being sought.


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stormbird
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Reged: 04/28/04

Loc: Western Idaho
Re: Need advice on mechanical quality of zoom binos new [Re: Jae]
      #5657549 - 02/02/13 03:21 AM

I have the Nikon 8-16x40 XL binoculars. Sharp as any binos I have ever owned (30+). They are much smaller than your requirement, but very handy. At 8x the fov is fairly tight, but better at 12-16x. My 2 cents.


Quote:

Probably off topic from original poster of large zooms but.....

I always heard that the one zoom exception is the 8-16x40 XL Nikon zoom. So when I checked one out, I personally found that it was certainly usable and sometimes convenient.

But it's costly and nowhere to be found....

Jae




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CuriousOne
member


Reged: 01/22/13

Re: Need advice on mechanical quality of zoom binos new [Re: stormbird]
      #5657602 - 02/02/13 05:49 AM

Specs are fine, but instead 8-16x40 I'd prefer 16-32x80

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Rich V.
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Re: Need advice on mechanical quality of zoom binos new [Re: CuriousOne]
      #5658256 - 02/02/13 02:18 PM

The above now discontinued Nikon zoom is the only zoom binocular that I've ever heard positive reports about.

I'm sure BillC has had some of those pass through his hands over the years; he could tell us if there's anything to it or whether it's just the luck of the draw for those owners. I'd trust Nikon to do a better job of it than some of the other suppliers we've been discussing...

Rich


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Sean Puett
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Re: Need advice on mechanical quality of zoom binos new [Re: Rich V.]
      #5661286 - 02/04/13 08:41 AM

I had some of the Zhumell zoom 10-30x50 binoculars. They were pretty good for daytime use if you are not overly critical. They were only $50 new so you need to factor that in. Night time use was another matter. They weren't perfectly collimated so that was part of the issue. Then when you zoom, it made collimation errors worse.

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CuriousOne
member


Reged: 01/22/13

Re: Need advice on mechanical quality of zoom binos new [Re: Sean Puett]
      #5670897 - 02/09/13 03:11 PM

Tomorrow, I'll post a series of photos, which shows what I was questioning about, and what I got as answer

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SMark
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Re: Need advice on mechanical quality of zoom binos new [Re: Simon S]
      #5707894 - 03/01/13 10:15 PM

Quote:

You will find none of the High end binocular manufacturers selling zoom binoculars, although Nikon ans a few others do sell a zoom to cater for public demand.





This one REALLY caught me by surprise...

A Fujinon Zoom... Really?


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hallelujah
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Re: Need advice on mechanical quality of zoom binos new [Re: SMark]
      #5708024 - 03/02/13 12:31 AM

http://www.ebay.com/itm/BUSHNELL-POWER-VIEW-BINOCULAR-7-15X-ZOOM-PRISM-SYSTEM...

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