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Binocular Heat

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Binocular Heat

Postby S I H on Sun Feb 19, 2012 1:32 am

Dear All
My binocular Steiner 10x26 Safari roof prism , was left on car dashboard in direct sun for several hours. The bin was in it's own (black) case. When recovered, the binocular was hot to touch ! It was left to cool in shade. The bin does not show obvious damage to body or the optics. Performance seems OK. Please let me know, what damage, if any, may have occurred to lenses, sealing, collimation etc. The newer Steiner catalogue lists temperatures -30 to +70 as safe. Probably due to non-metalic Makrolon body. Please advise how to check my bin for function or damage. Thanks in advance. S I H 19-2-2012

Re: Binocular Heat

Postby Jne_K on Sun Feb 19, 2012 6:55 pm


Bad idea to leave a bino in a car, of course, but we've all done it. The biggest danger is to the seals, because that kind of rapid heating causes them to expand to the max, then back to contracting as the temp drops. What this means is that there is a chance of the binoculars fogging, internally, due to seal failure under extreme conditions. If your Steiner hasn't fogged, I would just say it was a close call, but no harm done. I would, however, keep an eye on it for a bit and watch for fogging.
Thanks for posting with us
Joanie K - Your personal optics expert


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