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Factory collimation vs self-collimation discussion

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#1 decep

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Posted 28 April 2019 - 11:38 AM

I recently picked up a used pair of Zhumell 20x80 giant binoculars.  I own multiple telescopes, but this was my first pair of "astronomy" binoculars.  Before buying, I performed a little due diligence research to get a feel for the general consensus of how they perform and what to expect.  Of particular interest was "collimation" which I fully expected to have to perform.

 

I found many posts where people had purchased and returned low priced binoculars--sometimes 3-4 times--with the only reason being the binoculars were not factory collimated.

 

Coming from the world of telescopes, this attitude seems very bizarre to me.  I understand [telescope] refractors do not usually require collimation, but all reflectors, no matter if you spend $100 or $20,000, require self-collimation.  Collimation comes with the territory.

 

I suppose I could understand if you spent $1,000+ on a pair of binoculars and expect them to be reasonably collimated out of the box, but not at the sub $200 price point.

 

Am I missing something?


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#2 ngc7319_20

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Posted 28 April 2019 - 12:14 PM

Often binoculars are not designed for easy collimation.  Eccentrics on the objective lenses require special tools... spanner wrench at minimum... custom made spanner for that exact bino model preferably.  Some have prism adjustment screws that can be accessed under plastic or rubber coverings that can be re-glued afterwards.  Others require disassembly of the eyepiece holders to access the screws, and then dry nitrogen purge afterwards.  Not quite like collimating a Newt or SCT.


Edited by ngc7319_20, 28 April 2019 - 12:15 PM.

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#3 TOMDEY

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Posted 28 April 2019 - 01:22 PM

Yep, you could and should develop the capability to ~collimate~ your various binos at home. Start with Bill Cook's books and then get the tools to perform the 3-axis collimation. If your binos are only for your personal use, "conditional" 2-axis collimation will suffice... but anyone with eyes closer or farther apart than yours might not be able to use them. Far as I can tell, most hobbyists don't care to develop that capability at home. I worked at Bausch & Lomb, back when it actually was a full-capability optics company, not-yet morphed to only contact lenses and eye drops. Several of us (typically engineers) built home shops. Ralph Dakin (yes, that Ralph Dakin!) set up a complete Bino refurb shop at home with bench collimator etc, etc. and all the tools. He also knew every make and model and how to tune them up!

 

My opinion is that it borders on insanity to ship binos like the APM 100 out for collimation... when you could do them at home, in half an hour... and even tune them to your own personal viewing comfort!    Tom

Attached Thumbnails

  • 110 APM dedicated spanner 60.jpg
  • 111 80 adjustable spanner wrench B.jpg

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#4 ngc7319_20

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Posted 28 April 2019 - 03:37 PM

Yeah, someone needs to invent "Bob's Knobs" for binoculars... Couple thumb screws sticking out here and there...


Edited by ngc7319_20, 28 April 2019 - 06:38 PM.

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#5 decep

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Posted 28 April 2019 - 03:49 PM

I guess when I say collimate, I am mainly referring to aligning the prisms.  The posts I have seen indicate some [qualified] people are not even willing to adjust the prisms when the only obstacle is the rubber cover.

 

Of course, I suppose there is one aspect to adjusting binoculars... if you do not know the prisms are physically situated and you do not know how the collimation screws function, it is quite literally, a black box.  Adjusting the screws is just "magic".

 

I have adjusted prisms before, but the prisms were still a bit of a mystery until I took apart an old pair of Tasco binoculars.

 

It just seems like you would expect an $100 pair of giant binoculars to require a little adjusting.



#6 tomykay12

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Posted 28 April 2019 - 05:47 PM

Well, if they were meant to be field adjustable, wouldn't the adjustment screws be accessible without dissection of the coverings? 


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#7 ngc7319_20

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Posted 28 April 2019 - 06:39 PM

I guess nothing would stop someone from poking holes in the rubber covers, and replacing the little set screws with thumb screws...  Hmmm....


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#8 TOMDEY

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Posted 28 April 2019 - 07:39 PM

I guess nothing would stop someone from poking holes in the rubber covers, and replacing the little set screws with thumb screws...  Hmmm...

Taking that approach to its logical terminus... we should have little strings sticking out, here and there, attached to out appendix, spleen, aorta and Reticular Formation.



#9 MartinPond

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Posted 28 April 2019 - 08:07 PM

"

Am I missing something?

"

 

The most important missing thing is....

complaints about new large high-power binoculars (like 20x80) are very common,

and complaints about new lower-powered binoculars (like 7x35, 7x50, 10x50) are extremely rare,

even at under $100.

It would be a hasty generalization to leave the size of the binoculars out of a statement. 


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#10 Jon Isaacs

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Posted 28 April 2019 - 09:06 PM

Coming from the world of telescopes, this attitude seems very bizarre to me.  I understand [telescope] refractors do not usually require collimation, but all reflectors, no matter if you spend $100 or $20,000, require self-collimation.  Collimation comes with the territory.

 

 

Collimating a telescope means centering the optical axes of a single tube.

 

Collimating binoculars is something different, it means aligning the two halves so they point at the same point.  This must be done so they are within spec for all distances as well as IPD's (InterPupillary Distance).

 

Collimating the halves can actually throw an individual side out of collimation with itself.

 

Jon


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#11 Galaxy_Mike

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Posted 28 April 2019 - 09:30 PM

I have celestron 20x80''s, probably about the same as zhumell, and possibly came out of the same factory.

 

I assume I'll have to collimate or conditionally align them myself. And it's relatively easy,  and you might be able to pick up a suitable tool at the Dollar store for a few bucks or less. 

 

Then you have the binoculars with the eccentric rings. I think they hold collimation a lot better, but harder to adjust, and get the proper tool to break the rings free. I think the reverse porro were a bit different, but relatively easy?

 

Roof prism you supposedly can't do anything about the collimation. A lot of those are under $200, although I'm not aware of big roof prism binoculars

 

Id rather be able to collimate in house, in case there's a big comet or something. Hate to have to send out then. But, maybe eccentric rings wouldn't have a problem.  But still, stuff can get dropped. 

 

Enjoy your 20x80s, saw about 30 galaxies in mine Fri  night!



#12 decep

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Posted 28 April 2019 - 09:45 PM

Well, if they were meant to be field adjustable, wouldn't the adjustment screws be accessible without dissection of the coverings? 

I had the same thought, but binoculars are handheld devices and meant for less controlled environments vs telescopes.  Dropping binoculars is almost expected.  Adjustment screws are probably covered for protection.



#13 Vondragonnoggin

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Posted 28 April 2019 - 10:00 PM

I recently picked up a used pair of Zhumell 20x80 giant binoculars.  I own multiple telescopes, but this was my first pair of "astronomy" binoculars.  Before buying, I performed a little due diligence research to get a feel for the general consensus of how they perform and what to expect.  Of particular interest was "collimation" which I fully expected to have to perform.

 

I found many posts where people had purchased and returned low priced binoculars--sometimes 3-4 times--with the only reason being the binoculars were not factory collimated.

 

Coming from the world of telescopes, this attitude seems very bizarre to me.  I understand [telescope] refractors do not usually require collimation, but all reflectors, no matter if you spend $100 or $20,000, require self-collimation.  Collimation comes with the territory.

 

I suppose I could understand if you spent $1,000+ on a pair of binoculars and expect them to be reasonably collimated out of the box, but not at the sub $200 price point.

 

Am I missing something?

How many sub $200 binoculars have you collimated?

 

How long did it take you to get comfortable peeling up glued rubber covering to get to collimation screws on brand new binoculars? I ask because some people are on real limited budgets and not great at DIY stuff they don’t understand fully and might not be as comfortable as you sound with the process.

 

have you ever found a pair you wanted to collimate and could not find adjustment screws? 

 

How long did it take to collimate them your first time? How much faster were you doing it the second time?

 

Do you need any specialized tools?



#14 Rich V.

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Posted 29 April 2019 - 12:31 AM

I recently picked up a used pair of Zhumell 20x80 giant binoculars.  I own multiple telescopes, but this was my first pair of "astronomy" binoculars.  Before buying, I performed a little due diligence research to get a feel for the general consensus of how they perform and what to expect.  Of particular interest was "collimation" which I fully expected to have to perform.

 

I found many posts where people had purchased and returned low priced binoculars--sometimes 3-4 times--with the only reason being the binoculars were not factory collimated.

 

Coming from the world of telescopes, this attitude seems very bizarre to me.  I understand [telescope] refractors do not usually require collimation, but all reflectors, no matter if you spend $100 or $20,000, require self-collimation.  Collimation comes with the territory.

 

I suppose I could understand if you spent $1,000+ on a pair of binoculars and expect them to be reasonably collimated out of the box, but not at the sub $200 price point.

 

Am I missing something?

Do you understand the difference between the state of true binocular "collimation" and "conditional alignment"?  Collimation is where both optical axes and the central hinge axis are made parallel (which generally requires a test bench setup at a shop) which makes a bino aligned through the full IPD range. With conditional alignment, the user may tilt the prisms on one side or the other (or both!) to get merged images at one point of their IPD arc.  Neither side may have best intra-barrel alignment; both could be tilted way out of whack yet still be merged at that one IPD.  The resulting conditional alignment may or may not get you anywhere near true collimation, nor provide you with optimal views due to excessive tilt in the optical system (like a misaligned reflector).

 

Does that matter to you?  It's not necessarily a requirement that a bino be truly collimated; that depends on your individual needs or standards. Do you view alone and never share?  Alignment at one IPD may be sufficient.  If you share the bino with others having different IPDs, though, you need one that's collimated.

 

Rich


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#15 Jon Isaacs

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Posted 29 April 2019 - 12:46 AM

I had the same thought, but binoculars are handheld devices and meant for less controlled environments vs telescopes.  Dropping binoculars is almost expected.  Adjustment screws are probably covered for protection.

 

Best not to drop any binocular.  However, however binoculars like the Zhumells and Skywatcher 15x70s do not need to be dropped, they'll shift collimation with just normal handling.

 

Read carefully what Rich V. wrote, his explanation is better than mine.  

 

Collimation is more than just adjusting a prism.

 

Jon



#16 Ant1

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Posted 29 April 2019 - 05:57 AM

Hi

 

Most big binoculars will shift commimation with just normal use. Exactly like a telescope does. This is mostly due to the lack of stiffness of the housing, and even a slight deformation of one part will shift some parts of the optical train relative to others. High magnification make the problem obvious.

Big binoculars which don't shift collimation exist for military application but their housing is usually precision machined from bronze alloy and their weight makes them a difficult to handle instrument. Lightweight consumer grade binoculars are a lot easier to handle but be prepared to tinker with these any day (the cheapest ones get out of collimation the quickest...)

 

Regards,

Ant1



#17 ngc7319_20

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Posted 29 April 2019 - 06:20 AM

Taking that approach to its logical terminus... we should have little strings sticking out, here and there, attached to out appendix, spleen, aorta and Reticular Formation.

Just dont tell Cigna, ok?.... shocked.gif


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#18 Gyna

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Posted 29 April 2019 - 07:21 AM

...

Dropping binoculars is almost expected.

...

 

I feel sick just thinking about the sound of a falling binoculars...

 

Marco


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#19 TOMDEY

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Posted 29 April 2019 - 10:28 AM

Collimating a telescope means centering the optical axes of a single tube.

Collimating binoculars is something different, it means aligning the two halves so they point at the same point.  This must be done so they are within spec for all distances as well as IPD's (InterPupillary Distance).

Collimating the halves can actually throw an individual side out of collimation with itself.

Jon

Yep; contextual ambiguity in the world of optics! And add to that, Bill Cook's complete three-Axis Binocular Collimation! (where the hinge is the third axis).    Tom



#20 Galaxy_Mike

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Posted 29 April 2019 - 10:42 AM

Here's the oberwerk page for conditionall alignment:

https://oberwerk.com...mariner-series/

It's not really that hard I guess, though a bit on the picky side. I don't enjoy it but I've thought about getting a pair of celestron 7x50's because the screws are generally pretty easy to turn on new binoculars, as opposed to something that's stuck, on old ones.

I was looking through an ornithologist's pair of rood prism binoculars and felt pretty good about my efforts on my pair I had with me. Better alignment though not perfect, and I didn't have to send mine in for an expensive repair.

I think even Bill Cook told me he could be OK using conditional alignment, if he didn't have a shop.

I suppose it's a bit nerve wracking the first time you try it, pulling back the cover, but if the screws aren't stuck a cheap set of jewelers screwdrivers should be all you need bur be sure that your binoculars have the screws and not eccentric rings etc

Edited by Galaxy_Mike, 29 April 2019 - 10:44 AM.


#21 Vondragonnoggin

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Posted 29 April 2019 - 11:13 AM

Yes, conditional alignment is an option we have for binoculars out of warranty or exchange date after purchase as well as possibly contacting a binocular repair and service shop to do it, but for brand new binoculars still within exchange period or warranty, you would think that having them properly collimated would be better than digging into them yourself and voiding warranty or exchange terms to conditionally align them.

 

Probably why those folks mentioned by the OP have exchanged their new uncollimated pair for another pair that is collimated.

 

Some people buy new products to use as intended without having to futz around trying to fix a problem that shouldn’t be there in a new binocular in the first place and might require some dissassembly of a brand new optic.

 

Believe it or not, some people even return new telescopes with pinched optics or improperly working focusers rather than take it apart themselves to fix it. 

 

I guess it would make sense that not everyone wants to be a handyman with their new gear.

 

I believe Newtonian telescopes would be different because collimation is an expected task and why they make great products like laser collimators, refractor collimating eyepieces, and such to accomplish the task or if intended, have adjustment screws easily accessible like in the case of EMS Matsumoto binobacks or the adjustment screws on reflectors, SCT’s, most refractor focusers or push/pull lens cells, etc


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#22 Cory Suddarth

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Posted 29 April 2019 - 07:21 PM

Am I missing something?

"

The most important missing thing is....

complaints about new large high-power binoculars (like 20x80) are very common,

and complaints about new lower-powered binoculars (like 7x35, 7x50, 10x50) are extremely rare,

even at under $100.

It would be a hasty generalization to leave the size of the binoculars out of a statement.

 

While Running the repair and optical testing department at Orion (Watsonville, CA) in the late 90's, every 70mm and larger got de-boxed and set up on a tilting table in front of a C-8 laser set up as part of a go, no-go collimation test. I got Garrett Optical Tulsa set up with a similar rig. They (Orion) only randomly tested collimation on the 50mm and under sizes. I still work on large military binoculars as well as the Chinese consumer grade stuff you guys are referring to (I believe).  Large binoculars need and use large heavy prisms. And unbelievably undersized everything holds the Chinese stuff (optics) in place compared to military. While it might seem like an unfair comparison, the consumer grade designs are clearly done so for cost savings. Super small, low quality screws, prisms epoxied in place, but with no securing straps. Stuff like that makes these extra delicate. Just my two cents worth.

 

Cory


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#23 MartinPond

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Posted 29 April 2019 - 07:49 PM

Yup...it's the same now.  

And yet the sensitivity of the image to displacement is (power) * (aperture...thus fl) worse.

I googled for 20x80s.....it seems over 90% are from $90 to $140.  The chassis, where the

prisms are, is small, usually less than a plain 7x50.  I suppose you could make the prisms

smaller at 20x, given the EPs, but it seems even odd thermal expansion of the long plastic

barrels would skew things....

 

We have 20x80 Skymasters here, but rarely take them out.

They can be adjusted easily, but they are ~1985. Still...

And they get handled like a baby with spinal damage when we do use them.  


Edited by MartinPond, 29 April 2019 - 07:51 PM.

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#24 Neil Sanford

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Posted 29 April 2019 - 10:24 PM

Here are the APM collimation instructions.  I am most interested to read all forum comments on them.

 

https://www.apm-tele...Version_1_3.pdf

 

Later edit:  By googling "cloudy nights apm binocular collimation" I learned all I need to know (and plenty more).  My initial error was searching on (my) APM 70.  All issues relevant to my 70 were discussed in this forum (how could I doubt it) under threads on the APM 100 & 120. 


Edited by Neil Sanford, 30 April 2019 - 08:07 AM.


#25 FrankL

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Posted 30 April 2019 - 10:15 AM

Here are the APM collimation instructions.  I am most interested to read all forum comments on them.

 

https://www.apm-tele...Version_1_3.pdf

 

Later edit:  By googling "cloudy nights apm binocular collimation" I learned all I need to know (and plenty more).  My initial error was searching on (my) APM 70.  All issues relevant to my 70 were discussed in this forum (how could I doubt it) under threads on the APM 100 & 120. 

These instructions do not describe collimation. They describe conditional alignment.  




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