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How are roofs colimated? (1 Viewer)

CliveP

Well-known member
Are they collimated or are the prisms just placed in the barrels and rely on those to do the alignment?

The reason I ask is I think my Pentax 8x20 DCF ED are out judging by the eyestrain I'm getting in my right eye and the last time that happened was with a Hawke Sapphire which when replaced by Hawke completely eliminated the problem although in both cases there was never any double image so it's hard to tell but I don't get eye strain from my other bins and that includes my very similar RSPB 8x20 HD.

So I think they are buggered. I put in a query to Pentax but probably won't hear anything for a few days given it's the weekend.

I don't think this Pentax is as bad as the Hawke was so it's taken me a while to be sure that the Pentax is causing me the eyestrain but it seems pretty much certain now and could partly explain why I've been having some difficulties with it when trialing it outdoors.

Hoping that I can get it fixed as working properly it could be very nice.

Hope Pentax will be able to help.

One thing I do notice is that the prisms are not mirror symmetrically aligned but I'm not sure if this is even important. The right one is about 180 deg rotated compared to the left i.e. the sort of arrow side to the prism looking at the eyepieces is pointing NE on the right and SE on the left side when the left I think should mirror the right side and point NW???

In other words the right side prism is upside down. Actually this might just be the problem as when I turn the bin upside down and try the right side just with my right eye it seems less straining.

I think writing this I may have worked through the problem ;)

I doubt this though as I've never found orientation to affect my roof prism monoculars but it does seem less straining when I rotate the bin 180deg and try the right side again???

Ok maybe it's not that as when I try the rotated left side it's still much clearer than right side so maybe some fuzziness in the right side but the right side does get less fuzzy when it is rotated.

Ok I'm confused and I'm sure anyone reading this is now also. The eyestrain is definitely real though. That is a certainty.

If I don't get anywhere with Pentax (already got ticket request ref no. back from them to respond to my query within two days) I might be tempted to wrench the right eyepiece off and rotate the prism. It looks as though it is just threaded to the main body of the bin. That's if it becomes a nothing to loose situation as it seems now that I will not be able to use them as they are and ok I will loose any gas filling if there is any but if it fixes them otherwise it has to be worth a try as what I have seen with them as far sharpness, contrast, general quality of view is good and impressive.
 
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CliveP

Well-known member
Ok, pulled the eyepiece off. Curiosity got to me.

I see the prism with 4 retaining screws around the prism holder rim base so I guess these are adjusted to accomplish collimation or else they are just holding it there as how would they tilt it?

Seems I will need to remove the leatherette grip to get at these but I'll wait to see what Pentax come back with but I now think I could sort this fairly easily myself ( I did it with my Carson 7x18 the other day) although I might need a new leatherette part but maybe that's easy enough got?

One way or the other it's gonna get worked on.

Disappointed it wasn't just a matter of popping out the prism and rotating it but we live and learn as they say.

I'll mull it over in my bubble bath :)
 
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CliveP

Well-known member
I think I sorted it.

Seems it was collimation and the screws are for adjusting but it's an awkward system so I can see how it could easily be out after manufacture assembly or maybe a knock of some kind but the 4 screws seem to hold firmly so I doubt this.

I still have to see how they fare outdoors but from indoors I've been able to use them without getting any further ache and they are just all-round better. More equal sharpness in both sides and much better focus with resulting sharp image and I seem now to be able to use them with a wider ipd even fully extended so fuller view and eye positioning seems to have improved so a lot to be gained and lost with collimation.

I actually adjusted both sides in the end and I also swopped eyepieces and prisms between barrels to see if I could sort out the slight softness in the right side and I seem to have sorted that also.

It's easy to see how they could have been collimated a bit out during assembly as it is a very fiddly system that can easily become off until everything is tightened and even the final tighten can knock them out a little again so I spent a lot of time getting it as best as I thought it could be and I think I got it which is actually pretty good so I'm pleased with that and glad to know a bit more about it but that should be it firmly set now.

I accidentally touched one of the prism surfaces and in trying to clean it some smear is left so I should have been more careful but really it's just cosmetic and not affecting the bin. Once you get anything on a prism its basically impossible to get it factory clean as far as I know especially these caged roof prisms.

Tomorrow I will replace the leatherette (after checking them outdoors first just in case they could do with another tweek or something weird happens with them?) as they came off without damage and that will be that. No visit to Pentax required I expect.

Not recommended to do this on your best bins. This pair are a spare I bought cheap - probably sold by some-one who got eyestrain with them - so no real risk to my attempting this repair and I could always have sent them to Pentax to get professionally serviced and still can but I expect it's about £60 min for them to look at it so seems I will avoid that for now. I'll try and get a quote for info anyhow but way more important is that I do seem to have made an improvement to them from pretty painful and difficult to use for long to good or very good.

So if they work well outdoors in a real test and I don't see why they shouldn't then that will be fantastic. I may even perform a similar op on some of my other bins just to fine tune them remembering to be extremely careful with the prisms next time athough I managed to have no problem with the second prism or any of the lenses so all in all I think an improvement and worthwhile. It's actually quite good fun but a bit of a puzzle.
 
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ronh

Well-known member
No expert here, but have read that the final collimation on better roofs is made through eccentrically mounted eyepieces. The convention seems to be to do the tweak on the right side, which has been blamed for the commonly worse optical performance of that telescope than the left. It sounds easier than opening up and adjusting the prism.

I have adjusted a Porro having eccentric objectives. I gave it careful thought, but trial and error would probably have worked just as well. I guess eyepiece adjustment would be essentially the same thing.

Ron
 

CliveP

Well-known member
Hi Ron

Yes I would love some lab type specialist setup if that really would make a difference but in the end of the day with these roofs it's just 4 grub screws N,S,E and W more or less and and if you tighten one it moves it towards that direction or loosen it for away.

With porros it's easier as you only have one screw for N & S and one for E & W.

I adjusted my little reverse porro the other day a bit haphazardly but I've been using it since (although not outdoors yet) and it's great.

This roof is tricky. I'm getting a good view but I think I'm still getting eyestrain and the left side still seems a bit softer so I think it's putting more strain on my right eye to focus and therefore tiring it out maybe. I still think the collimation is improved though and hope to get a try outdoors with them later today but I'm now starting to suspect it may be a problem with the objective or focussing lens on the right side and then it needs to go to Pentax.

I've just done a bit of an A-B with my RSPB and I get no eyestrain with that especially on the right side and it's sharp there also so I think there is something wrong with the Pentax in that regard. It's looking like an expensive trip to Pentax after all.

I've just realised I can screw the objectives off and swop them to see if it transfers the problem from the right to left side. So that's my next move. Worth a try.
 
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WJC

Well-known member
Hi Ron

Yes I would love some lab type specialist setup if that really would make a difference but in the end of the day with these roofs it's just 4 grub screws N,S,E and W more or less and and if you tighten one it moves it towards that direction or loosen it for away.

With porros it's easier as you only have one screw for N & S and one for E & W.

I adjusted my little reverse porro the other day a bit haphazardly but I've been using it since (although not outdoors yet) and it's great.

This roof is tricky. I'm getting a good view but I think I'm still getting eyestrain and the left side still seems a bit softer so I think it's putting more strain on my right eye to focus and therefore tiring it out maybe. I still think the collimation is improved though and hope to get a try outdoors with them later today but I'm now starting to suspect it may be a problem with the objective or focussing lens on the right side and then it needs to go to Pentax.

I've just done a bit of an A-B with my RSPB and I get no eyestrain with that especially on the right side and it's sharp there also so I think there is something wrong with the Pentax in that regard. It's looking like an expensive trip to Pentax after all.

I've just realised I can screw the objectives off and swop them to see if it transfers the problem from the right to left side. So that's my next move. Worth a try.


Hi Clive:

You may perform a very good conditional alignment—for yourself, or Someone with your IPD—by following the instructions plastered all over the Internet. However, if you are going for TRUE 3-axis alignment (real collimation), in which the bino is aligned for all user (all IPDs), you will find those instructions fall very, Very, VERY short of doing the job, possibly causing you to do more damage than good. In addition, through the Internet, one could get the idea that the prism-tilt convention is all there is, ignoring the eccentric ring, push-pull, and 3-point eyepiece adjustment conventions, altogether.

When it comes to collimation, so many armchair experts . . . Aren’t! :cat:

Good luck.

Bill
 

Troubador

Moderator
Staff member
Supporter
Clive

This eyestrain in your right eye.
Have you considered that you might be winking at the girls too much?

Lee
 

CliveP

Well-known member
Hi Clive:

You may perform a very good conditional alignment—for yourself, or Someone with your IPD—by following the instructions plastered all over the Internet. However, if you are going for TRUE 3-axis alignment (real collimation), in which the bino is aligned for all user (all IPDs), you will find those instructions fall very, Very, VERY short of doing the job, possibly causing you to do more damage than good. In addition, through the Internet, one could get the idea that the prism-tilt convention is all there is, ignoring the eccentric ring, push-pull, and 3-point eyepiece adjustment conventions, altogether.

When it comes to collimation, so many armchair experts . . . Aren’t! :cat:

Good luck.

Bill

What is this mythical True 3 axis alignemnt you speak of as I've never ever seen a bin with it and I've seen quite a few. Where's your adventure spirit Bill and your chirpy cheerfulness?

I'm off out to do a short test and see if my effort is any good. If it isn't I can just bin them as I've had enough but I may just have got it sorted or they may do for a few spare parts or I could see if I could jam the remaining clean prism into my 6x16 monocular to give it a turbo boost. The possibilities....

Actually I messed about swopping the objectives and it made no difference so I contacted Pentax again or rather their service contractor which they referred me to. I then realigned the prisms as I had described way back and this time took the bins outside to collimate them and I seemed to get a good result with the sharpness returning to the right side of the bins and I even seemed to get a vast improvement in glare resistance performance as these bins had been really bad with sun before but this time much much better so I'll go for a little trial and hope they continue to give a good impression.

Took them out earlier before I worked on them again and tried them on the way to the supermarket and so so thoughts on them then but I let a worker in the supermarket try them breifly and his comment was " wow very high magnification", lol. Yes 8x.

Going to take my 8x20 monc along also as I reconfigured the eyelenses in that a few days ago so will see how that goes.
 
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WJC

Well-known member
What is this mythical True 3 axis alignemnt you speak of as I've never ever seen a bin with it and I've seen quite a few. Where's your adventure spirit Bill and your chirpy cheerfulness?

I'm off out to do a short test and see if my effort is any good. If it isn't I can just bin them as I've had enough but I may just have got it sorted or they may do for a few spare parts or I could see if I could jam the remaining clean prism into my 6x16 monocular to give it a turbo boost. The possibilities....

Actually I messed about swopping the objectives and it made no difference so I contacted Pentax again or rather their service contractor which they referred me to. I then realigned the prisms as I had described way back and this time took the bins outside to collimate them and I seemed to get a good result with the sharpness returning to the right side of the bins and I even seemed to get a vast improvement in glare resistance performance as these bins had been really bad with sun before but this time much much better so I'll go for a little trial and hope they continue to give a good impression.

Took them out earlier before I worked on them again and tried them on the way to the supermarket and so so thoughts on them then but I let a worker in the supermarket try them breifly and his comment was " wow very high magnification", lol. Yes 8x.

Going to take my 8x20 monc along also as I reconfigured the eyelenses in that a few days ago so will see how that goes.

Hi Clive:

If purchased new, EVERY “bin” you’ve seen has had it! That’s why a 6-footer can hand his binocular to his 6-year old daughter with both of them enjoying the same good image. The last time it was addressed in literature for consumers was 1953.

It is not “mythical.” I recognized it back in 1976, have fought to get the reality recognized for 40 years, and finally got the concept recognized by SPIE in 2012 and published in their magazine PROCEEDINGS.

Please read the attached PDF, and you will see why my “chirpy cheerfulness” has been brushed aside trying to wrest inaccurate notions from those who would help their neighbors screw up their binos by saying all you need to collimate your binocular is a roofline and a screwdriver.

Bill

PS The reason you haven’t seen Conditional Alignment is because I coined the term. But, fortunately, it has been used, referenced, and explained on BF, and other forums, many times over the last few years.

I was speaking about the condition with a professor at the University of Arizona’s Optical Sciences Center, and in mentioning the “problem,” he said: So!?

I told him to think about it, and the phone got really quiet for a while. Then I heard:

Oh … Oh, my … OH, MY!!!

A few hours later, I was invited to give a lecture on the topic at the 2012 SPIE Conference in San Diego. The PhD types never have a need to address the issue and the public doesn’t even know they should. It was a harsh reality that needed a name and, having worked with binoculars for decades, I gave it one.
 

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CliveP

Well-known member
I was thinking of changing this armchair to the expert model but no I think I will keep this old battered genius ass repository but I don't like to brag, much. I am quite surprised by how my field test went though as I wasn't entirely optimistic about it.

Ok the results of the field trial are in and I do believe the ^**"£$%^&* thing works. Not only that I was quite impressed with the monocular also except for the glare whereas the Pentax handled glare very well for a change.

Basically it seems to behave like a normal (compact) binocular now and I haven't got any eye ache or headache so something must have gone right. It's not like you put it up to your eye and go holy whatever that's amazing, more like oh that's good , that works, that is useful for it's size, very sharp and you get some pretty nice views but they are still compact views as per the bin.

So I think I'm satisfied. If I bought a new 8x20 and it worked like that while I don't think I would be raving about it I would find it acceptable and think it functioning properly and now I actually think I will take it along quite a lot though my Vistron 8x25 would still in general outperform it but then it is larger and doesn't fold down.

The eye positioning is not a problem now and it's easier to use the bin with the eyecups in any position of extension whether down or up. It does now just remind me of a smaller Vistron with better quality glass etc but with a correspondingly smaller view but one which is still ok given that I seem to have transformed it from unusable to working.

Whether it works for others with different IPD is getting further down the road than that which I was aiming to accomplish.

The Pentax service will only quote for repair after they inspect the bin and you need to pay £24 to get it back if you don't want to go ahead with whatever they subsequently quote but I don't think I need to bother with that now. They won't be able to improve it any further in any noticeable operational way and I have a new working RSPB HD 8x20 in any case although they do have different colour/brightness/contrast outputs and I like both. Hard to choose a favourite but the RSPB probably is the winner with the most contrasty brightness and it takes a lot to have more than the Pentax.
 

WJC

Well-known member
"Whether it works for others with different IPD is getting further down the road than that which I was aiming to accomplish."—CliveP

That’s a totally respectable and realistic position! On occasion, I have done a conditional alignment on one of my own binoculars, when nothing more was needed. I, too, was not worried about anyone else; most had their own binos and my kids are LONG grown.

I just get wrapped around the axle when people start talking about how the “collimated” their binocular, when I know bloody well they haven’t, and that, more often than not, they have taken their bino farther away from a clinical collimation job by following the silly, screw tweaking instructions plastered all over the Internet. Of course, it’s mostly a matter of semantics. But, it’s a matter of semantics that can take the uninitiated down a costly road.

I’ll bet that even with what you have done, you are relying heavily on your spatial accommodation to make the images acceptable. I have had customers tell me the collimation on their binos was perfect, even when the collimator showed the instrument to be out of alignment by 5 or 10 times the most lenient industry standards.

My whole gig was: if they’re happy, I’m happy for them. BUT, please guys, don’t call it what it’s not!

Good viewing.

Bill
 

NDhunter

Experienced observer
United States
Bill:

I find the collimation information is interesting. I just got an old Japanese 7x35 monocular,
of porro construction. It has a pleasing view.

How do I check to see if it is in proper collimation ?

Jerry
 

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ceasar

Well-known member
Bill:

I find the collimation information is interesting. I just got an old Japanese 7x35 monocular,
of porro construction. It has a pleasing view.

How do I check to see if it is in proper collimation ?

Jerry

Jerry,

Try closing one eye and then look through it!;)

Don't wink!;) with either eye!:-O


Bob
 

WJC

Well-known member
Bill:

I find the collimation information is interesting. I just got an old Japanese 7x35 monocular,
of porro construction. It has a pleasing view.

How do I check to see if it is in proper collimation ?

Jerry


Hi Jerry:

Now, we're getting deeper. The short answer—although not thorough, but MORE thorough than you need—is that ... you don't.

Collimation may refer to the alignment of the optics in a single telescope. However, it almost exclusively refers to the parallelism of THE TWO TELESCOPES. Thus, in the immortal words of Aristotle:

“Don’t worry; be happy.” :cat:

Bill
 

NDhunter

Experienced observer
United States
As you may have suspected, I was just trying to get some
attention. o:D

Bill, you were too nice you should have read me the riot act !

Jerry
 

WJC

Well-known member
As you may have suspected, I was just trying to get some
attention. o:D

Jerry


Heavens, no! I have been asked so many questions over the years that would bring one to think of the common sense challenged, I took you seriously. Besides, I know what those cold North Dakota winds can do to the brain.

And, too, you have to remember, this is America, where guns cause crime, spoons cause obesity, marriages cause divorce, and pencils cause spelling errors. :cat:

Bill
 

WJC

Well-known member
Bill, you were too nice you should have read me the riot act !

Jerry

Nope! I'm saving that for the marginal humanoids who want me to milquetoast all my comments. I have always liked and respected you—as so many of the others. There are others who I think should take a long walk on a short pier.

Bill
 

Steve

Surfing
Staff member
United Kingdom
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ronh

Well-known member
Curious times we live in, when three axes (left telescope, right telescope, and connecting axle) being parallel is politically incorrect. But I will be nice, and try to be offended.

Ron
 

WJC

Well-known member
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How are roofs colimated?
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This is the reason that the user gave:

This persons constant derision and name-calling when referring to people who don't see things his way is sickening. It has no place on a public forum. Can the moderators *please* do something about this???

This message has been sent to all moderators of this forum, or all administrators if there are no moderators.

Please respond to this post as applicable.

I AGREE PLEASE TAKE NOTE OR GO AWAY

Well, it is obvious that you’re speaking of me, so I have to give you one.

Recently, I did embark on name calling; I’m just human. But, were you around to see any of the unwarranted, inaccurate, and hurtful barbs that were thrown at me? Or, was that all right because I stand by fact in a world of speculation?

Did you note that I voluntarily left BF for 90 days just to make a detractor happy? Would you have done so? Do you think other detractors would have done so?

Before I offer more evidence of support, I would like to address a portion of your comments.

“...when referring to people who don’t see things his way is sickening.”

My way? I suppose by that you have evidence of something (technical) I have said that was wrong? If you do, I think you owe it to the forum to point it out, along with the credentials you posses that give you the wherewithal to highlight it as such. I think that’s fair and honorable; don’t you? By doing so, you can edify the group and put me in my place at the same time. If you can’t find fault with anything technical I have said, you’ve lost 50% of the wind from your sails. And, with me falling on my sword for my errant behavior, it would seem the other 50% as well.

PLEASE KEEP IN MIND THAT I THOROUGHLY ADMIT, WITHOUT THE SLIGHTEST RESERVATION, THE ERROR ON MY PART. I SHOULD HAVE BEEN BIGGER; I’M SORRY. And, are you aware that one who seems able to read minds has accused me, on the open forum, of saying “I’m sorry” when I “never” really mean it. But, when I have even been chastised for just trying to defend myself, I often feel trapped and confused.

Just today, on the open forum, I read:

“Bill: Now all should see how your knowledge and help is a great thing. Keep up the good work. Jerry”

[Please read post 3 through 6 on the Broken Binoculars thread. Tell me, how many times have you gone to sleep past 2 or 3 in the morning because you were trying to thoroughly answer the questions of someone in need. I’m prepared to be impressed. I have done it many times and, to date, it hasn’t put so much as a nickel in my pocket.]

And, last week, one of your own countrymen wrote:

“People from Yorkshire, UK, are renowned for 'telling it as it is' Take no notice and keep posting your views.”

You say I get upset when people don’t see things MY way. But, when do FACTS have anything to do with somebody’s opinion? At the risk of offending again, I see BF as a room to learn in, not a sandbox to play in. And, I am aware that there are those who want BF to be the home of endless speculation, and that anyone who comes along to help the HONEST TRUTH SEEKER in a non-milquetoast fashion is seen as some kind of enemy—to some, anyway.

Sadly, I don’t see it that way. One would think if I were that bad that Ed (PhD), Ronh (PhD), or Holger (PhD) would put me in my place. Yet, it seems that those who want to cause a conflict are those who lack that understanding and think BF was created for nothing more than chatter. I respect that view to a point, and hope you will come to respect mine ... to a point.

I allowed myself to be pushed over the edge by a couple of guys who obviously had no respect for what I was trying to do; I am working to curb my feelings. I didn’t put in my 40+ years in optics to be a hotdog; it was just a byproduct of loving my career and trying to put food on the table. But, if I can help someone with an honest need, I will use it to do so. And, I’m sorry, but there will always be those offended by straight talk. And, after working face to face with binocular customers for many years, I’ve come to learn that, in order to really be of service, you have to take on some things with a 50 megaton show of force. I wish it were not so; I truly do. But then, I didn’t set the rules for trust and attention spans. :cat:

Cheers,

Bill
 
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