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Do all binoculars have individually focussed eyepieces?


Gissajob
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I'm looking to buy a pair of bins, but I have a specific question which I'm wondering if anyone has the answer to. My eyesight in my left eye is significantly different to my right eye due to the fact that I had a cataract a couple of years back. This means that I really need a pair of bins where I can focus the eyepieces indvidually. BinocularSky reckons that most bins do this, but I'm looking at the Helios NatureSport 10x50s on FLO, and it doesn't mention this. The Revelation 10x50s are also a possibility, but again not sure if they have this feature.

Anyone have either of these who can answer the question?

Thanks

Alan

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I've never seen a decent binocular that doesn't allow for this , usually it's just the right-hand EP that's adjustable .

You focus the binocular with the main wheel with your left eye only , then close the left and tweak the right-hand side with the diopter adjustment with your right eye until it's focused.

Both sides should now be tuned to your sight and further focusing is done with the main wheel only.

It's worth noting the setting on the right for future use , the EP will have a scale on it , usually from -3 to +3.

It's worth giving FLO a ring to check though.

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I've always found that individual focussing bins are better for astro in that when they're focussed they're less likely lose their focus.

The Helios Apollos are a good example but they only come in the 7x50 .....or 10.5x70 and above. They also start at about £180 .......but they are good.

I found centre focussing to more prone to slipping when above 45º but these were larger bins , 20x80s and 25x100s so the smaller bins maybe less prone to this.

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The only binoculars I have encountered that don't permit some degree different focusing for each eye are the "focus-free" (i.e. fixed focus) ones and anything of a Galilean configuration (opera glasses, cheapo plastic binocs in part-works and "suitable for 6 years and over" naturalist and commando kits). However, those with independently focusing eyepieces tend to have a wider range of focus (nominally +/- 4 dioptres on the ones I have) than the centre-focus and right dioptre adjustment ones (nominally +/- 2 dioptres on the RDA).

Both the binoculars you mention are of this latter configuration, but I do not know what the RDA dioptre range is on either -- you should probably ascertain whether it is adequate for you.

Also, I think I recall Pete Gamby saying on here somewhere that he could arrange for the focus of some of his (Opticron) binoculars to be altered to individual needs. Might be worth getting in touch.

Edited by BinocularSky
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Thanks everyone for your information. I was fairly sure this would be the case, but good to have it confirmed.

Also, I think I recall Pete Gamby saying on here somewhere that he could arrange for the focus of some of his (Opticron) binoculars to be altered to individual needs. Might be worth getting in touch.

Now, funnily enough I noticed some Opticrons on FLO which looked good. A bit more money than the others, but not silly money. So I may go for those.

Thanks for the info!

Alan

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Just to reassure you about the Helios Naturesports. I have a pair and they do have focus adjustment on the right eyepiece as well as central focussing controlling both eyepieces so you should be fine with them. They are lovely binoculars and I would recommend them.

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How do focus-free bins work?
They are set at a hyperfocal distance for people with normal eyesight (usually around 25m/80ft). They then rely on having a depth of focus that will then cover infinity to half the hyperfocal distance, relying on the focus mechanism of your eye. This is aided by use in bright conditions where the contracted pupil increases the depth of focus. Fine for the young; less good for us older people with presbyopia....
Especially for people with dodgy eyes (like me)?
They probably don't. :laugh:
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Just to reassure you about the Helios Naturesports. I have a pair and they do have focus adjustment on the right eyepiece as well as central focussing controlling both eyepieces so you should be fine with them. They are lovely binoculars and I would recommend them.

Thanks Hobbes.

Steve - presbyopia? Is that an ability to see Scottish churches clearly?

Alan

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