Dropped Binoculars out of collimation? (1 Viewer)

[Carless]

Dear all,

I have a pair of 20x60 Tento binoculars, which we've had for some years.

Unfortunately, my partner dropped them onto concrete. They now have double images. I'm not knowledgeable about the workings of binoculars, but figure that it won't be worth the cost of getting them professionally fixed.

Is there anything I can try to fix them. I found this page on collumating binoculars http://www.cloudynights.com/item.php?item_id=416 but I don't know how to open up the binoculars to access the prism adjusting screws.

Any advice?

 

[Simon Wates]

Its best not to open them up yourself - I don't think it costs so much to have them done - someone from the UK will recommend somewhere I'm sure.

 

[MSA]

If you decide not to go down the professional repair route, and just want the binoculars to be functional (if not completely weatherproof), you could try unscrewing one of the objective lens barrels slightly. When I was a 13 yr old birder with bins from the local Exchange and Mart and no money for repairs (paper rounds didn't pay that well!), I found that slight double-vision could be cured thus! It's only an option prior to chucking the bins though, and a proper repair would be best.

 

[Carless]

Its best not to open them up yourself - I don't think it costs so much to have them done - someone from the UK will recommend somewhere I'm sure.

I looked into it, and it seems that it will cost £60-£70 plus postage to have them fixed at http://www.binoculars-uk.co.uk/optical-repair-service.html

That's many times more than they cost in the first place. Though, they're difficult to find.

 

[typo]

Might be best to give a repair company a call. These seem to be the two place that get the most mentions on the forum, but I have no personal experience of either.
Glasgow Binocular repairs.
0141-248 7179
and
http://www.opticalrepairs.com/notices.htm

David

 

[Carless]

If you decide not to go down the professional repair route, and just want the binoculars to be functional (if not completely weatherproof), you could try unscrewing one of the objective lens barrels slightly. When I was a 13 yr old birder with bins from the local Exchange and Mart and no money for repairs (paper rounds didn't pay that well!), I found that slight double-vision could be cured thus! It's only an option prior to chucking the bins though, and a proper repair would be best.

I found a thread online where someone fixed the Tentos like this, though it may have been more luck than design. It seems that they have rings to adjust the prisms, rather than screws. It looks as if learning more about them before trying anything will be a good idea. So, I'm looking for more information.

How do you unscrew the objective lens barrel? I can unscrew one of the rings from around the lens, but even if I take it off, there's no obvious way to change anything concerning the lens itself. And removing the ring and putting it back on doesn't change the double image problem (and hence the collimation is not changing I would presume).

I did see another thread where someone said that nobody ever learned anything about binoculars unless they had a pair that they were prepared to experiment on with the risk of ruining them. Since the binos are unusable now, and it seems uneconomic to repair, I might at least have a go.

 

[kensinten]

I can recommend this chap for repairs:

http://www.intrasights.co.uk/

He's repaired a pair of Zeiss for me recently, cost should be less than £50 for collimation/cleaning.
I've re-colimated cheaper bins myself in the past just using trial and error but I've also wrecked a pair by overtightening the prism screws and chipping a prism. If they're worth less than £50 you may as well have a go yourself, it's either that or throw them away.

 

[Carless]

I can recommend this chap for repairs:

http://www.intrasights.co.uk/

He's repaired a pair of Zeiss for me recently, cost should be less than £50 for collimation/cleaning.
I've re-colimated cheaper bins myself in the past just using trial and error but I've also wrecked a pair by overtightening the prism screws and chipping a prism. If they're worth less than £50 you may as well have a go yourself, it's either that or throw them away.

They cost me £20. Before I spent a lot of money on them, I'd certain want to watch ebay for some time to work out what they going rate is.

 

[kensinten]

It seems that they have rings to adjust the prisms, rather than screws.

Normally the collimation is adjusted by screws on porro-prism bins (which I assume that 20x60s will be). The eccentric ring ajustment is more often found on roof prism bins and is extremely difficult to adjust without the correct equipment and some experience. It's always possible that misalignment after a fall can be corrected by re-seating the barrels where the impact has been taken by the rim of a barrel but more likely the prisms have moved slightly.

 

[MSA]

How do you unscrew the objective lens barrel? I can unscrew one of the rings from around the lens, but even if I take it off, there's no obvious way to change anything concerning the lens itself. And removing the ring and putting it back on doesn't change the double image problem (and hence the collimation is not changing I would presume).

This may not be applicable to your make of bins, but with the ones I had as a lad you'd just grasp the barrel and twist clockwise whilst looking through eyepiece - there was a screw thread where the barrel joined the body of the bins.

To be honest, for a £20 pair of bins that had already served me well, I'd be tempted to try dropping them again to see if that worked!

 

[kensinten]

They cost me £20. Before I spent a lot of money on them, I'd certain want to watch ebay for some time to work out what they going rate is.

It's not what you paid for them it's what they're worth to you. Sounds as if you got them for a good price anyway. I've just sent off a pair of old Dekarems for repair, the repair will cost much more than I paid for them a few years ago but they'll still be a pair of damn fine bins once they're fixed.

There are a couple of pairs of 20x60 Tento bins on Ebay ATM, might be worth having a bid?

 

[Carless]

It's not what you paid for them it's what they're worth to you. Sounds as if you got them for a good price anyway. I've just sent off a pair of old Dekarems for repair, the repair will cost much more than I paid for them a few years ago but they'll still be a pair of damn fine bins once they're fixed.

There are a couple of pairs of 20x60 Tento bins on Ebay ATM, might be worth having a bid?

I might have a try, but my standard ebay bid strategy is to bid low for a while until I work out the prices things go for, then bid realistically. There are no completed auctions for me to look for.

Advice on which 20x60 or better (e.g. 20x80) brands and models are similar to the Tentos would be appreciated.

Edit: Maybe 20x80 would be too heavy - the Tentos are already quite heavy. Reviews suggest that the Celestron 25x70s are worth considering.

 

[FrankD]

Carless,

I wish I could help with suggestions on this one but binoculars of this size/configuration are not something I tinker with regularly. Binoculars of this configuration are usually more in the realm of amateur astronomers. The "cloudy nights" forums are great for this type of info. They even have a subforum relegated specifically to addressing binocular suggestions/usage. I often see the Celestron Skymaster 15x70 referenced there as a potential candidate for those on a tight budget. Quality control is hit/miss though from what I have read.

Hope this helps some.

 

[Carless]

Eventually I gave up on these. My partner claims they are still usable, but I just can't get on with one eye observation or bins out of collimation. I eventually decided I couldn't afford really good bins, so I've just bought a cheap pair of bins. Reading reviews and reading between the lines, I don't think I'm as fussy as some. A few weeks ago while part of a nature group I viewed a dog across a lake with both some Aldi zoom binoculars, and a £700 pair of Nikons belonging to someone who was guiding our group. No surprise that the Nikons were obviously better, but it made me think that I can still be satisfied with less than the best. Another in this group had an identical pair of Tentos to ours.

Tentos didn't turn up enough on ebay, and the ones that did sold for many times what I paid for ours. So, eventually I gave up and ordered a pair of these: http://www.picstop.co.uk/celestron-skymaster-binocular-25x70 The reviews on Amazon (where they cost £100 instead of £70) seem quite good, though they are a bit mixed - I hope I get a good pair. There is of course the distance selling regulations if I get a bad pair.

I'm not expecting the optics to be as good as the Tentos, but at least I'll have a pair of working large magnification binos to go with our Pentax Papillios. Thinking about it, the Papillios cost the same as the Celestrons I've just bought, and we've had years of enjoyable use out of those. So maybe it's not unreasonable to hope that the Celestrons will be as good for us as they have been for some of the amazon reviewers.

 

[Simon S]

Just check the objective housing has not cross threaded. There tough as old boots these, but the weak spot in the housing to binocular body joint.

 

[Carless]

Just check the objective housing has not cross threaded. There tough as old boots these, but the weak spot in the housing to binocular body joint.

(assuming that you mean the Tentos)

I couldn't get any part of it to unscrew. The only bits I could get off were the plastic seals around the objective lenses. The rest looked old and ultra-solidly screwed and slightly corroded together. Eventually I ended up using full body force to try to get them to unscrew and nothing doing. That was part of what made me give up.

When the Celestrons arrive, presumably in the coming week since they've been dispatched, I'll know whether I did the right thing or not.

 

[Carless]

The Celestron binos are OK. They're a bit cheap looking - but then they are cheap. But, I can look through them and see things. The image isn't the best - I don't think the optics match up to the Tentos. But they're new, and the Tentos were old, and now broken. So, I'm happy with the Celestrons for the price I paid. The carry bag (can't call it a 'case') for them is exceptionally cheap looking.

 

[Jon Turner]

I once repaired some slight discollimation by hitting the object lens with a heavy book! Good as new!

At 20 quid you're not going to much worse off!

I wouldn't do it to a decent pair!

 

[paj1234]

Same thing happened to me, with Tento 10x50s. Here is how I fixed them:

https://www.ifixit.com/Guide/Repairing+Tento+10x50+binoculars+Image+alignment+(Collimation)/35230

 

[Binastro]

Carless,
. The Celestron 25×70 that I have is pretty dreadful, regarding resolution and chromatic aberration.

The Tentos can be excellent if they are Soviet era. You can tell the year they were made from the serial number. The many later Russian 20×60 binoculars that I've tested are very much worse in comparison. After the breakup of the Soviet Union they still carried on making them but to a much lower standard.

I have a specially selected Soviet 20×60, which is as good as they come.

All of the repairers mentioned above should be okay, and also Action optics would be good as he was the repairer for Soviet binoculars originally.

The Glasgow repairer is excellent.

The fact that the binocular cost £20 is not really relevant if you have a high quality Soviet era 20×60.

The cheap Chinese 70 mm binoculars are fragile, although the Revelation 15×70 can be good if you buy one that is in collimation and don't knock it.

A repairer might charge about £60 for a complete clean and re-collimation, which is well worth it if you have a really good Soviet era 20×60, but not if it is of lower quality.