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Equipment Discussions >> Binoculars

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hallelujah
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Reged: 07/14/06

Loc: North Star over Colorado
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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Reged: 06/16/04

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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
Carpal Tunnel
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Reged: 06/19/07

Loc: LEVITTOWN, PA
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
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: 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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Reged: 06/18/08

Loc: Ottawa, Ontario, Canada
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
Close Enough
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Reged: 04/10/04

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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Reged: 06/16/04

Loc: San Diego and Boulevard, CA
Re: Need advice on mechanical quality of zoom binos new [Re: KennyJ]
      #5637647 - 01/22/13 08:09 PM Attachment (14 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
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: 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
member


Reged: 01/22/13

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
scholastic sledgehammer
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Reged: 08/29/11

Loc: Atlanta, GA USA
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
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: CuriousOne]
      #5638383 - 01/23/13 08:16 AM

yes.

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Jon Isaacs
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Reged: 06/16/04

Loc: San Diego and Boulevard, CA
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
member


Reged: 01/22/13

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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Reged: 01/02/05

Loc: Lake Tahoe area, Nevada, USA
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
sage


Reged: 10/21/09

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
member


Reged: 01/22/13

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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Loc: Cambridge, MA, USA
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


Reged: 10/21/09

Re: Need advice on mechanical quality of zoom binos [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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