Checking collimation at home (1 Viewer)

[William Lewis]

Hi All.

So I picked up a pair of opticron srga's a few weeks back for sentimental reasons- they were just about to be discontinued and I used them extensively when I first got back into birding properly in my 20's after a few years of birding hiatus when my favourite past time changed for a period to getting smashed.

They didn't seem quite right and I wasn't sure if it was collimation, I can usually see if a bins way off alignment instantly but these were ok just not quite as sharp as I remembered and I wasn't sure if I'd just been spoilt by the view of my regular bins.

So I did a bit of googling and ended up doing a star test, very small hole in something very opaque with a bright light behind it in a dark room. Stood about 10m away, focused the non diopter eye piece precisely, wound the diopter till the diopter eye piece was really blurry and checked if the sharp point of light in the non diopter eye piece was in the middle of the blurry circle of light from the diopter eye piece.

It wasnt, it was slightly off to the right but still within the circle. Before I send the bins back into opticron (I've read a bit about proper loads of axis' collimation and am certainly not attempting it) though I just wanted to check if my methodology was correct and if anyone else has the same problem and this helps solve it all the better!

Thank in advance.

Will

 

[Foss]

The test I use is to focus the binoculars on a telephone pole with cross-beams at the top, a block or so away. Then shift the binoculars so the EPs are a couple inches away from your eyes. Close your eyes for one second and open them suddenly. Repeat a few times. Any colimation error should show up as ghost image of the cross-beams.

 

[William Lewis]

Thanks Foss. I did try that method but I don't think the collimation is "off" enough for it to be obvious, also as there 8x32's it's a struggle to line up the exit pupils at distance.

 

[WJC]

220806

If I ever mention my books by name, Lee will whack my wrists ... that hurts. So, I will just offer images of the covers. Book #1 has 38 pages on collimation vs. conditional alignment which has been accepted as fact by SPIE (the Society of Photo-Optical Instrument Engineers) and Book #2, which is a 68-page expanded treatise on the same subject.

So far, I have pointed out that the “collimation tips” on the Internet are 100% ... WRONG! And will only work if the error is small and the observer’s accommodation for a misalignment is adequate. Furthermore, I know that the ego-driven wannabe’s get their noses bent out of shape if I say anything that deviates from the pabulum-soaked information they try to promote. (This is the fourth time I have pointed out that I was NOT speaking of Foss or any of the other real players. There will not be a fifth.)

However, with 52 years in the industry and more than 12,000 repair and collimation jobs under my belt, and the respect of the serious players on other continents. I think I’ll just continue doing things my way.

Besides, it’s the empty wagon that makes the loudest NOISE.

“When I first came to Cloudy Nights, I thought you were the biggest jerk in the world. Since then, I have used several binoculars. I see you have been right straight down the line. You have taught me a lot and I thank you.” — Mttafire

 

[William Lewis]

Hi Bill

I was hoping an expert may weigh in at some point and your pretty much the world expert in collimation if I'm not correct.

Flattery will get me nowhere but given I have no optical measuring equipment at home some practical advice might.

I know I can't test collimation properly at home but if you were in the same situation as me and most binocular users how would you test if there out before troubling/paying a professional to test it thoroughly and correct any misalignment?

 

[WJC]

Hi Bill

I was hoping an expert may weigh in at some point and your pretty much the world expert in collimation if I'm not correct.

Flattery will get me nowhere but given I have no optical measuring equipment at home some practical advice might.

I know I can't test collimation properly at home but if you were in the same situation as me and most binocular users how would you test if there out before troubling/paying a professional to test it thoroughly and correct any misalignment?

Hi William,

Thanks for the kind words. I hope you know you will probably be burned in effigy for it. The most hated man is the one who tells the truth.

First, if you have to TEST for collimation precision, you don’t really need to. The eye / brain combination is a pretty neat arrangement. Some people like to quantify ... everything. Even when such renders no real value to the observer. Thinking that way helps raise the bar of optical understanding. The problems arise when the those who know little about the subject want to convince others their opinions are tantamount to facts. That builds ego but damages the craft.

Secondly, precise “measuring equipment” is very nice to have (see attached). But for one who knows what he or she is after, there are workarounds.

A collimator is just a large bore telescope backwards and the auxiliary scope is easy enough to build or buy. Too many people, however, find it much easier to pontificate than it is to do what needs to be done. Having a graduated reticle is also very nice (also attached). However, the superimposition of two dots of light is all that is required.

“When one is in water over his head, he does not need to know how deep the water is. He needs to know how to swim.”

Cheers,

Bill

 

[William Lewis]

Thanks Bill. Swimming lessons it is!

What would your method be of overlaying 2 dots of light with the usual stuff people tend to have around there homes, what distance would you use between them and how would you set up the binoculars and at what distance with regard to the lights?

P.s the first book with the yellow cover (naming no names!) looks an interesting read for me, where's it available?

 

[WJC]

No

Thanks Bill. Swimming lessons it is!

What would your method be of overlaying 2 dots of light with the usual stuff people tend to have around there homes, what distance would you use between them and how would you set up the binoculars and at what distance with regard to the lights?

P.s the first book with the yellow cover (naming no names!) looks an interesting read for me, where's it available?

All are available for amazon.com

 

[William Lewis]

Hi Bill.

That's a shame for the current discussion but it's your knowledge and entirely up to you whether to share it or monetize it. I can understand both perspectives.

Interestingly this is the thread i've had most PM's from offering advice which is all most welcome, I might check in with the members concerned and post up some anonymised responses for the sake of the discussion.

Will

 

[Ted Y.]

Oh no! A new prolonged series of retaliatory, vengeful, or hostile acts or exchange of such acts??
Please tell me I am wrong about it.

 

[William Lewis]

Hi Ted.

None such thing, I'm just trying to see if my bins are straight!!!

 

[William Lewis]

One response -


outside of the usual trick- put it on tripod or ledge or stable platform that allows you to view easily at a suitable target, a utility pole with crossbar or perhaps a squarish building with a line at the top that's flat - perhaps a shingled roof. Aim the bino's at the target, step back perhaps 12 inches and look through the eyepieces and see how the images align. You might even try slightly further away and adjusting the IPD on the bino's and see if that makes a difference in alignment. I commonly use the star test with a bright star and a dark night- aiming at the bright star and defocusing the diopter side and then seeing how the 2 images overlap- again on a tripod or stable view mount of some sort. Off topic a bit, but do you go for eye checkups yearly? They do change and people sometimes have differences from the norm that make bino usage a bit problematic. I'd say that if you look at the object, then pull back momentarily and the eyes have to adjust back to stereo vision, then you have a miscollimation. Have a friend with good vision and bino experience? Having a second opinion might be helpful.

 

[Brink]

Here is a simple and effective way to do it with items you have around the house. I’ve used this method a number of times.

5 - Nuevos artículos - Collimation of Binoculars with a Lamp, a Mirror and a Screen (recommended)

Method for Collimation of Binoculars Based on Projection of Images of a Lamp after Reflection on a Mirror By Rafael Chamón Cobos Created September 2017 Last update April 2021 (added collimation with 8 screws) Last update July 2023 (added values of misalignment of the binculars under test versus

sites.google.com

 

[William Lewis]

Cheers Brink. When I get a minute or 20 I'll try all the methods and see what they produce. Thank you!

 

[Maljunulo]

Sounds brilliant to me, but I’m really not qualified to judge that.

 

[Binastro]

There are two things here.

Seeing if a binocular is out of alignment for one IPD.

And correcting it if the binocular is out of alignment for one IPD.

Personally, I have little problem seeing if there is a problem.
Either I get a slight headache or just see that the two images are not merged.

If there is no problem in long term use, then the binocular is fine for me.

The binocular might be in conditional alignment just by luck for my IPD or it may be properly collimated.

If there is a problem then I will either get it professionally collimated or put it aside for attention at a later date, which may mean I never get it fixed.

If the binocular is new and from a reputable source, one just needs to send it back for repair or replacement.

If one wants to attempt a repair then it is at the owner's risk.

B.

 

[Hauksen]

Hi,

The binocular might be in conditional alignment just by luck for my IPD or it may be properly collimated.

What's the difference between conditional alignment and proper collimation?

Regards,

Henning

 

[Binastro]

Proper collimation is where all the axes, mechanical and optical are parallel.

Conditional alignment is where the alignment happens to be correct for one IPD, but if the binocular is opened or closed alignment is lost.

No doubt I will be corrected if I have got this wrong.

Although there used to be many technicians able to use a collimator correctly and provide full collimation, in this throwaway society there are very few able to do this properly now.
Some may know how to do it correctly but take short cuts to make their work profitable.

Regards,
B.

 

[pat mitchel]

I agree with Binastro; As the thrifty (more like miserly) purchaser of many older porros, conditional alignment is the most I can manage most of the time. As I am the only user, it's not a problem for me +- 1 degree either way. Regards, Pat

 

[WJC]

Hi,



What's the difference between conditional alignment and proper collimation?

Regards,

Henning

I have addressed this many times in lectures, articles, and books since 1972.