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Eccentric Ring Collimation on a Fujinon 14x70

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#1 ailevin

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Posted 23 July 2005 - 10:34 PM

I have recently acquired some very surplus Fujinon 14x70s. While they are in mechanically rough shape, the optics look pretty good to me. The former owner demonstrated the removal of the locking ring on one objective and displayed the eccentric rings. The fact that he had a homemade tool to remove the locking ring and could demonstrate how to collimate raises the question of whether the binoculars are currently well collimated. Assuming that collimation is necessary (A quick look during daytime did not demonstrate obvious severe miscollimation at my ipd), I have a few questions.

1. Is there an online description of using eccentric rings to collimate ?

2. What is the proper technique for me to perfect the conditional collimation for my ipd?

3. Who does Fuji service and repair? Is there anyone in the Southern California Area who can properly collimate them?

4. What will it cost to perperly collimate these binoculars?

Help and advice is appreciated. I was inspired by the current thread on modestly priced binoculars being delivered out of collimation, but did not want to hijack that thread.

Thanks,
Alan

#2 BillC

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Posted 23 July 2005 - 10:50 PM

3. Who does Fuji service and repair? Is there anyone in the Southern California Area who can properly collimate them?Thanks,
Alan


First, those binos need--and deserve--professional care, and if you don't have a real collimator--and I am not talking about some cobbled up misfit in plywood--and someone trained to use it, you're not doing justice to yourself or the bino.

Baker Marine (Brian Osterberg) on Shelter Island in San Diego will do a bang up job for you. Except for some Navy OM (Second Class or above) I wouldn't trust anyone else in CA with them.

This list has a lot of folks to make other recommendations. However, some of the techs thrive on folks not really knowing what to expect.

Boy, would I LOVE to say more on this. But, that's a tune for another day.

I don't know what Baker would charge, I would charge $80- to $120 if there were no broken prisms.

'Hope this helps.

Cheers,

Bill

#3 ailevin

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Posted 23 July 2005 - 11:32 PM

Bill,

I apreciate the quick response, and I'm probably pushing on a bruise here (justice and injustice), but that servicing would double my investment in these binos. I don't know how they have been fiddled with previously, whether they have a seal anymore (former owner doubted it) etc. Visual inspection down barrels, exit pupils, daytime look through were quite good. Just got enough break in the fog here to spot Jupiter and sitting back 6 inches from oculars I can see miscollimation. I need to check the spacing of the moons to estimate it.

Is reasonable to expect that I can get decent conditional collimation by fiddling myself? Also, will my attempts make it any harder for a professional to do it right?

Thanks,
Alan

#4 BillC

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Posted 24 July 2005 - 01:44 AM

Bill,. . . Is reasonable to expect that I can get decent conditional collimation by fiddling myself? Also, will my attempts make it any harder for a professional to do it right?

Thanks,
Alan


It is not reasonable that you will get it right as an amateur without a collimator. HOWEVER, if the error is small, and if you only deal with one side, and if you are going to be the only one using the instrument, there should not be a problem.

It is not "sealed" at the objective, but it DOES have a nice greased "o" ring. That helps make things more uniform in collimating with the rings.

Will your work make it harder for a professional tech? Probably. But, not much. If you hear a bunch of sob stories and prices start getting raised, tuck it under your arm and leave.

Cheers,

Bill

#5 Claudio

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Posted 24 July 2005 - 02:53 AM

Hello Alan,

there are quite a few members able to describe with sketches and words how eccentric rings work, but please consider that:

conditional alignment = each optical axis is parallel to the other one but not to the mechanical axis.
Number of different conditional alignments you can get for your IPD: infinite

true alignment = optical axes are also parallel to the mechanical axis.
Number of conditional alignments you can get for your IPD: just one, and will work for every IPD

Only in true alignment the lenses of each barrel are all centered, allowing the binocular to get its best optical quality

My suggestions:

to learn more on collimation, spend few dollars for a cheap Japanese binocular of the sixties or seventies, play and learn with it. But don’t risk with your 14x70.

Moreover, you cannot be sure whether prisms are still squared or not. Not squared prisms can produce “alignment turbulence” especially far from the centre of the FOV.

So give to Caesar what is Caesar’s, and to the bino technician what is of the technician.
Even paying the overhaul, your 14x70 would still be a real buy.
But make sure he is really a binoculars specialist, there are tons of self-appointed bino technicians!

#6 KennyJ

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Posted 24 July 2005 - 02:57 AM

< So give to Caesar what is Caesar’s, and to the bino technician what is of the technician.
Even paying the overhaul, your 14x70 would still be a real buy.
But make sure he is really a binoculars specialist, there are tons of self-appointed bino technicians! >

Well put Claudio !

My thoughts exactly.

Kind regards ,

Kenny

#7 ailevin

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Posted 24 July 2005 - 02:34 PM

First and foremost, I really appreciate the thoughtful comments and good advice.

Now on to last night's science experiments. In my own defense, I probably should have described their condition in more detail, rather than simply using the term "very surplus." I'd like to describe it for the curious, but those who own well cared for Fujinon binoculars and are squeamish may not want to read what follows :shocked: .

The eyecups and any other eyepiece coverings are long gone. There is a sort of calibrated reticle that used to be in the right hand eyepiece (previous owner removed). He also mentioned that he had replaced or tightened some of the screws in the top housing covers. I don't know the proper term, but there is no plastic or rubber ring on either objective barrel, so you can see a metal sleeve with a notch in it protuding from each barrel, and inside that is a locking ring with two holes that imply a tool (spanner?) to remove it. Below the locking ring is a thin metal ring the same width as the locking ring with a tab that nicely fits into the notch in the sleeve. Below that are a set of two concentric and slightly eccentric rings that together are about the width of the locking ring. Moving one or both of these rings moves the objective laterally in the barrel. Once an adjustment is made, the ring with the tab goes in as a sort of pressure washer so you can screw in the locking ring without moving the eccentric rings. The previous owner added a couple 3" rubber pipe fittings that are pressed over the barrels which actually make decent objective shades and cover the objective end collimation hardware nicely.

As I said earlier, looking down the barrels there is nothing lose, cracked, obviously misplaced, or growing. The exit pupils are nice and round with the pleasing oversized prism look that I am used to in Fujinon binoculars. Of course I am no optical tech, and I'm sure a trained eye would see much more and be better able to diagnose these binoculas even upon casual inspection.

After looking at Jupiter last night, and knowing what direction I wanted to move the left objective, I was able to make surprisingly small adjustments to the eccentric rings to improve the collimation. The sensitivity was an indication to me of why I need to have it done professionally. BTW, I chose the left barrel to work on since that is the side on which the previous owner had demonstrated the collimation technique.

Through some miracle, I would estimate that the collimation at infinity for my ipd now looks like it is within 10 arc seconds. I judged this based on looking at a star with my eyes about 6 inches behind the oculars. I also tried defocusing the star slightly in one ocular to see how concentric the focused star was in the defocused star. This compares with an error previously of at least 2-4 arc minutes as judged by the spacing of the Galilean sats of Jupiter earlier in the evening.

I intend to do some dark site observing and compare these binoculars with my Obie 15x70s and Canon 15x45s next weekend. Then I will pay a visit to San Diego to get a professional opinion on the condition of the binoculars and cost to refurbish them.

Thanks again,
Alan

#8 EdZ

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Posted 24 July 2005 - 03:18 PM

Through some miracle, I would estimate that the collimation at infinity for my ipd now looks like it is within 10 arc seconds. I judged this based on looking at a star with my eyes about 6 inches behind the oculars. I also tried defocusing the star slightly in one ocular to see how concentric the focused star was in the defocused star. This compares with an error previously of at least 2-4 arc minutes as judged by the spacing of the Galilean sats of Jupiter earlier in the evening.



I suspect the good news is you seem to have these adjusted very close. But frankly, you could not see 10 arcseconds with a 14x binocular. If you can see any misalignment at all, then it is certainly greater than 10 arcseconds.

Have a look at the double star 100 Hercules, a very nice even mag6 double star, easily seen separated at 14x. Hold your eyes back 6" and let the merge drift together while you are looking at this double. Is the misaligment closer than this double? If not, it's not 10 arcseconds.

#9 ailevin

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Posted 24 July 2005 - 04:07 PM

I suspect the good news is you seem to have these adjusted very close. But frankly, you could not see 10 arcseconds with a 14x binocular. If you can see any misalignment at all, then it is certainly greater than 10 arcseconds.

Have a look at the double star 100 Hercules, a very nice even mag6 double star, easily seen separated at 14x. Hold your eyes back 6" and let the merge drift together while you are looking at this double. Is the misaligment closer than this double? If not, it's not 10 arcseconds.


Thanks Ed. I will try tonight or as soon at the sky is willing. As you correctly point out, my guess at 10" is probably overly optimistic, but I was estimating the possible error I could detect compared to the width of Jupiter in the binos which IIRC is around 30". With one ocular defocused on a star so that the blur was similar to the size of Jupiter, the star image of the other ocular seemed to be centered to the central third of the width of the blur as best I could estimate.

Alan

#10 EdZ

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Posted 24 July 2005 - 05:21 PM

To view a focused image inside a defocused image, i suspect your eyes have already gone beyond the stage of viewing the separation of miscollimation and have already pulled the images together. Once your eyes view the separation in the images, the next thing your eyes want to do is correct for it and overlap the images. Even on binoculars that are out by 3 or 4 arcmin, your eyes will pull the images together. So, either you have no real measurable misalignment, or your eyes are pulling the images together.

edz

#11 ailevin

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Posted 01 August 2005 - 10:15 AM

Have a look at the double star 100 Hercules, a very nice even mag6 double star, easily seen separated at 14x. Hold your eyes back 6" and let the merge drift together while you are looking at this double. Is the misaligment closer than this double? If not, it's not 10 arcseconds.


Ed,

Finally got an evening of dark sky observing in last night with the 14x70s. 100 Herculis is a nice double, reminds me of Nu Draconis, like two headlights, though fainter and closer. My collimation error is indeed greater than that separation, and it is slightly cross-eyed. (I think the proper term is converged?). Before I messed around, the error was larger and in the other direction, which I understand is more difficult for the eyes to correct without strain.

At any rate, I observed for several hours with no eye strain or headaches to report. Comparing these older 14x70s to Oberwerk 15x70s, the Fujis definitely show tighter star images, and the split on 100 Her was much cleaner. I read your comparison review of 70mm binoculars and will try for gamma Delphinus next time out.


I have not done careful side by side comparisons to estimate which one saw deeper, but it seemed pretty close looking for faint star chains in M24. Examining the binoculars in the daytime, the Obie's coatings seem to reflect less light and look a deep green/blue, while the Fuji coatings look clear (white). My 7x50 Meibos had dark green coatings if I remember correctly. Since these were IDF surplus, is it possible that their coating specs are different?

I also contacted Brian at Baker Marine about having the binoculars examined and professionally collimated/repaired as necessary. However, I don't think I will ship them out until after new moon. I'm having too much fun with them.

Thanks,
Alan


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