Binocular collimation

[sorrimen]

Hi all 

Sorry that this is a slightly lazy post, but I’ve seen a pair of bresser binoculars for £10 with the description being ‘slight double vision until adjusted to the bridge of your nose’. Looked up double vision w binos and saw that it’s normally miscollimation. Is collimation easy on binos? Do you reckon it’s worth grabbing these for a fun little £10 pair? https://www.gumtree.com/p/binoculars/bushnell-binoculars-10x50/1436317307

Thanks! 

Ross  

[DaveL59]

If you wanted them professionally collimated that'd cost several times more than the purchase price which on a cheap pair isn't worth it unless they are rare or of sentimental value. You might be able to align the prisms so that they work for you (conditional alignment) but a lot would depend on how they are built/assembled. I don't know if that one has tilt screws under the outer covering on the body or if you'd need to dismantle and use thin shims to tilt the prisms until they are aligned. There's info out there on the web, but random fiddling with the screws can make things much worse or even chip the prisms.

For sure a lot of patience, a good understanding about how to adjust and appropriate tools (good jewellers screwdrivers etc) would be needed as well as a suitable target to test against. Stars at night will do pretty well for the testing tho since its much harder for the brain to match up the dissimilar images in each eye with so little detail to stitch together.

Personally I'd pass, I think those often sold at Lidl so better to wait till they have them again and go in, check several pairs carefully and buy a pair that is already right 🙂 

 

Edited July 12, 2022 by DaveL59

[sorrimen]

1 hour ago, DaveL59 said:

If you wanted them professionally collimated that'd cost several times more than the purchase price which on a cheap pair isn't worth it unless they are rare or of sentimental value. You might be able to align the prisms so that they work for you (conditional alignment) but a lot would depend on how they are built/assembled. I don't know if that one has tilt screws under the outer covering on the body or if you'd need to dismantle and use thin shims to tilt the prisms until they are aligned. There's info out there on the web, but random fiddling with the screws can make things much worse or even chip the prisms.

For sure a lot of patience, a good understanding about how to adjust and appropriate tools (good jewellers screwdrivers etc) would be needed as well as a suitable target to test against. Stars at night will do pretty well for the testing tho since its much harder for the brain to match up the dissimilar images in each eye with so little detail to stitch together.

Personally I'd pass, I think those often sold at Lidl so better to wait till they have them again and go in, check several pairs carefully and buy a pair that is already right 🙂 

 

Thanks for the detailed response, Dave. In that case, I’ll keep working towards a good £100 pair! 

[BinocularSky]

As DaveL59 noted, it's usually miscollimation. The "until adjusted to the bridge of your nose" usually means "only looking through one tube" . Unfortunately, the Gumtree ad is no longer available, so I can't see which Bressers it is, but the very cheap ones are usually quite simple to conditionally align (full collimation is not easy without a proper optical bench). If you can let me have a pic of them, if it's one I've done in the past, I can send you details of how to do it.

[DaveL59]

9 minutes ago, BinocularSky said:

As DaveL59 noted, it's usually miscollimation. The "until adjusted to the bridge of your nose" usually means "only looking through one tube" . Unfortunately, the Gumtree ad is no longer available, so I can't see which Bressers it is, but the very cheap ones are usually quite simple to conditionally align (full collimation is not easy without a proper optical bench). If you can let me have a pic of them, if it's one I've done in the past, I can send you details of how to do it.

ahh you're braver than me then. While I'd take on a pair that are out if they were at the right price and have a fair few in the collection here, I balk to recommend to someone who's never tried/done this to avoid disappointment if things don't work out or get damaged 🙂  

[sorrimen]

13 hours ago, BinocularSky said:

As DaveL59 noted, it's usually miscollimation. The "until adjusted to the bridge of your nose" usually means "only looking through one tube" . Unfortunately, the Gumtree ad is no longer available, so I can't see which Bressers it is, but the very cheap ones are usually quite simple to conditionally align (full collimation is not easy without a proper optical bench). If you can let me have a pic of them, if it's one I've done in the past, I can send you details of how to do it.

Seems I missed out then! Very much appreciate the kind offer though, and if the slightly pricier pair I settle on somehow fall out of collimation I’ll be sure to send you a message.

[tony210]

Hi-I've collimated binoculars several times now and it is fairly easy with good quality pairs as they have adjustable prisms and using a star and doing slight adjustments on ONE prism only you can get there - if not sometimes rotating one of the objectives will achieve the same result - anyway always go slowly and do nothing you cant reverse- hope that's some help - best wishes Tony.

Incidentally it improves terrestrial viewing dramatically if you get it right.

Edited July 20, 2022 by tony210

[WJC]

[WJC]

And Stephen, the below is why I've been gone so long ............. I can't speak Hindi.

[Chaz2b]

Another thing to note, is that on cheap ( build not cost) binoculars the prisms can be held in place with only glue, constant battles with hard objects when travelling can losen the contact and problems really appear!

 I have also taken binos apart, more for my curiosity, but learnt a lot about their construction. I’ve also taken apart a pair of binoviewers, actually easy, learnt about their construction and enjoyed the experience. 
Some always advocate not to touch them if you have no experience, so how are you going to learn? 
If they are that cheap then it will be at worst a very inexpensive lesson.

chaz

[DaveL59]

45 minutes ago, Chaz2b said:

Another thing to note, is that on cheap ( build not cost) binoculars the prisms can be held in place with only glue, constant battles with hard objects when travelling can losen the contact and problems really appear!

 I have also taken binos apart, more for my curiosity, but learnt a lot about their construction. I’ve also taken apart a pair of binoviewers, actually easy, learnt about their construction and enjoyed the experience. 
Some always advocate not to touch them if you have no experience, so how are you going to learn? 
If they are that cheap then it will be at worst a very inexpensive lesson.

chaz

There's a certain degree of truth in that and in my case like you, learned by doing and buying cheap and fixing up. But those bressers retailed new for around £15, £20 tops IIRC so are they really worth spending £10 on when they're out of whack? There's better quality ones out there like older Swift models after all.

Another reason I didn't suggest it was easy (is it, to do it right?) is that I could easily see the outcome in picture C in WJC's post, some of the ones I've got hold of cheap were just exactly like that. Sure they seemed aligned when you look, images merge ok etc, but what you see is offset from what you aimed at. For me if looking at a bino that's misaligned generally it'd need to be one that I wanted for the collection or have some reasonable worth/rarity, like the Nikon Sportster EX 8x25 that I got also for a tenner and were out of alignment. A bog standard low-end porro pair I'd pass and look for something better. In my case I picked up a mint pair of Minolta Classic sport 10x50 WP for £22 a couple years back which I think were much more worthwhile and no work needed on those at all.

Unless there's an urgent rush to get something/anything then OK, but if prepared to wait and search, you can find the pearls scattered in amongst the dross. Sorry if OP feels he missed out because I suggested it wasn't worth it but that's the reason behind my thoughts. 

[tony210]

Some great points here- I think star alignment as with telescopes is the best way to go and was very satisfied when I realised I could bring the star images together- as the above shared article mentions when you get near your brain aligns the images so perhaps this will hinder perfection but most misalignments are gross and not minor in those binoculars I have aligned- Swift 8x42s have an excellent push pull screw system that made the process easy and they have stayed aligned. Interesting area but I would agree that as with many things the learning process is at least as  enjoyable as the result -hopefully!😀

Edited August 22, 2022 by tony210

[WJC]

Hi Tony,

As described, this is Conditional Alignment and not 3-Axis Collimation. Please see my post and pages from my book from August 13. If that does the trick, be happy. Just know there are downsides to CoAl. The brain wants to see things in alignment right away, and can be detrimental in the way described, if one is not careful. You are not just dealing with MECHANICAL alignment, but PHYSIOLOGICAL alignment as well. The first you can have total control over. On the later, you have almost NO control over. As Dirty Harry said: “DO YOU FEEL LUCKY!”

Any time I can off any assistance, don’t hesitate calling on me.

Cheers,

Bill

Edited August 22, 2022 by WJC

[sorrimen]

Hi all

A wealth of information and replies here! Still yet to purchase my binoculars, but if a good used pair come up I’ll feel more comfortable having all of this here. And don’t worry, Dave, my first plan is to buy new even after all this help so don’t think it was your comments that put me off! 

Thanks all

Ross

[DaveL59]

2 hours ago, sorrimen said:

Hi all

A wealth of information and replies here! Still yet to purchase my binoculars, but if a good used pair come up I’ll feel more comfortable having all of this here. And don’t worry, Dave, my first plan is to buy new even after all this help so don’t think it was your comments that put me off! 

Thanks all

Ross

Thanks Ross, I'm sure you'll find a good pair with patience 🙂

As I mentioned it can seem easy to adjust some, but as WJC points out it is also easy to get it wrong. The first pair I sorted didn't have those handy tilt screws, I had to make shims with tin foil to tilt those prisms. A long and frustrating trial and error tho I did get there and they hold perfectly since the overhaul. Some of the Swift porros and other unibody designs of that type are easier as Tony said, roof aren't quite so. Thing is some you adjust the collimation using offset rings in the objective rather than prism tilt so its harder to advise when not knowing the specific bino and also the person's potential skills, no offence meant there. Add in that most of us don't have the training and test kit that Bill has so the best we can hope for is to get it aligned enough to work for us and perhaps reasonably OK for some others, aligned as opposed to collimated.

If you do buy new and find they aren't quite right, don't fiddle, just send them back for replacement. Always best if you can to test them before you buy but not always possible of course. When testing I try to relax my eyes and be looking directly ahead rather than concentrat on the images presented as you'll naturally force the sides to merge. You could try looking through and have one side covered, then quickly uncover that side and see if the image initially jumps before merging. 

I do recall seeing reports of those Bressers like the ones you were interested in in Aldi/Lidl where some opened several boxes to find a pair that were aligned before buying, so either poor QC or they went out of alignment during shipping/shelf stacking. To me that says that even if they give a good view today, they're a pair that are likely to go out of alignment at some stage during use. Same can be said of some Celesteron and other large binos, can't recall the model but one series was said to go out of alignment if you simply looked at them 😉 

[WJC]

So many people seem to want to make binocular collimation a DEEP DARK SCIENCE! It's not! Twenty minutes of PATIENTLY reading—something more mature than that, "Look at a power pole or roof line and turn a few screws; it's so easy. Just like the doctor who gave me a brain transplant." My graduated reticle is wonderful. HOWEVER, the superimposition of two dots of light is all that is required.

"Any fool can KNOW. The point is to UNDERSTAND!" — Albert Einstein

Edited August 23, 2022 by WJC

[WJC]

Please Help: I have tried to shrink the last few graphics I have posted. But each effort has failed! For example, that least image would do the job if it were 1/8th the size.

[DaveL59]

3 minutes ago, WJC said:

Please Help: I have tried to shrink the last few graphics I have posted. But each effort has failed! For example, that least image would do the job if it were 1/8th the size.

not sure Bill, was it from a picture you added or a snippy that you pasted in?

Generally I open a photo then size it to suit by adjusting the photo viewer window size and then use the snippy tool to grab the bit I want and paste that in. Saves messing with suitable formats if you don't happen to have jpg or other supported file types.

Edited August 23, 2022 by DaveL59

[globular]

If you’re on a PC then

• edit the post
• hold CTRL and right click the image
• select edit image
• change the pixel size to be 1/8 of whatever it is
• making sure keep aspect ratio is selected
• click update
• save your changes

If you’re on a phone or tablet then I think double tapping the image does bullet points 2 & 3 in one go.

Edited August 23, 2022 by globular

[WJC]

Than you very much. 'Next time I post, I'll give that a try!