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Feb
18

So what can go wrong with binoculars?

So what can go wrong with binoculars?

The truth is almost anything that is man made can, and probably will fail, eventually! Binoculars are precision instruments and as such are vulnerable to misuse or mishandling. There is a lot of truth in the old saying that ‘you get what you pay for’ an expensive pair of binoculars from a manufacturer like; Swarovski, Leitz or Zeiss costing over a thousand pounds will be built to a much higher mechanical standard than a binocular costing less than two hundred pounds, and will consequently stand up to a lot more punishment than the cheaper pair will. That said, properly cared for, you can get some binoculars these days with stunning optical quality for a very modest outlay, but be warned, treat them with care and above all don’t drop them on to a hard surface from any sort of height, it will cause you pain and expense!

Generally speaking there are four major causes of binocular failure; Faulty manufacture; Wear and Tear; Accidental damage; Collimation problems.

Faulty manufacture

If your binoculars are within their guarantee period any fault, apart from accidental damage, is probably covered by the manufactures guarantee against faulty workmanship. If that is the case we would strongly advise you not to tamper with them in any way that might invalidate your guarantee. There is a list of contact details for all the major binocular manufacturers and importers in our ‘Links’ section. Make them your first port of call. Most if not all will deal with your guarantee repair quickly and efficiently, but if they don’t we are here for you to fall back on.

Wear and Tear

Can cover almost anything that can go wrong with a binocular in the fullness of time. All mechanical parts are subject to wear and tear and most of these type of faults are repairable, but some very cheap binoculars are just not built to last, if they loose their lubrication soft metal parts will wear quickly resulting in ‘focus lag’, ‘floppy optical tubes’ etc. These kinds of faults won’t affect the optical performance of the instrument but will severely diminish the pleasure of using it, to the point where you just won’t bother any more because it’s too much hassle. If we receive a binocular that we think is not economically viable to repair we will be frank and tell you that it’s not worth repairing because it is worn out!

Accidental Damage

Often the result of neglecting obvious signs of ‘wear and tear’. Top Tip – check your binocular carrying strap for any sign of wear to the strap itself or to the fastenings, and if you find any wear replace what is worn immediately. We see more binoculars needing repair or readjustment due to carrying strap failure than for any other reason. The results of most accidental damage can be successfully repaired provided spare parts are readily available.

Collimation problems.

By far and away the most common fault that binoculars suffer from are collimation problems. A binoculars collimation can be the result of any of the above problems and in some cases all three. So what is collimation and how does it affect binoculars. Wikipedia offers the following definition: Binoculars, field glasses or binocular telescopes are a pair of identical or mirror-symmetrical telescopes mounted side-by-side and aligned to point accurately in the same direction, allowing the viewer to use both eyes when viewing distant objects. The crucial part is that both halves of a binocular point accurately in the same direction, if for any reason they no longer point in precisely in the same direction the binocular is said to be out of collimation. Depending on how badly aligned the binoculars are, they can be mildly uncomfortable to totally unusable. If you feel that your binoculars feel like they are trying to pull your eyes out your head they are almost certainly out of collimation. The effect is the same as if you cross your eyes on purpose, and just as uncomfortable! The human brain, the most wonderful organ yet discovered in the universe, is very good compensating for minor misalignment of our eyes, it deals with the problem every day, and we have to have a pretty hefty smack to the head before the brain can’t compensate anymore and we see double. Collimation issues become more apparent as soon as we use binoculars because the greater magnification exacerbates the problem.

Unless a binocular has become so badly damaged that it is apparent that the two halves are pointing in different directions it is almost impossible to tell from the outside that a binocular is out of collimation. This is because the problem will almost invariably be with the alignment of the internal prisms. There are a number of reasons that binoculars lose their collimation. The most common cause is a drop or knock that physically moves the internal prisms. Another major cause which is less obvious is to leave a binocular in direct sunlight for a prolonged period. This can have a number of disastrous consequences for a binocular. The temperature internally can climb rapidly, the different materials that the binocular is made of will expand, probably at different rates, causing the materials to flex as the temperature rises, and go out of alignment. You may be lucky in so far that all the components contract to where they were before they got hot, but there is a very good chance they won’t and the next time you go to use them they will have lost their collimation.

In all but the cheapest binoculars it is possible to get them re-collimated but it is a job for the experts.

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