New glasses, maybe something is wrong. (1 Viewer)

New binoculars, maybe something is wrong.

Just got a Olympus 8x25 pc1, (porro prism) and its like the view is made of two circles overlapping(is that a word? im danish so..) eachother almost completely, but NOT completely, only like 95% or more. Is it normal? Or has it something to do with collimation?
Thanks,
Carsten J

keithdrengen said:

Just got a Olympus 8x25 pc1, (porro prism) and its like the view is made of two circles overlapping(is that a word? im danish so..) eachother almost completely, but NOT completely, only like 95% or more. Is it normal? Or has it something to do with collimation?
Thanks,
Carsten J

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I'm no expert, but that sounds like they're badly collimated. You should be able to get the two circles to overlap completely into one, as far as I understand.

Its worse when close to an object. Today i went to a store and compared with a Nikon 8x20 High Grade, and it showed the same issue with not overlapping completely( it was better though than my Olympus, maybe because of a wider field of view) so it might be normal.

keithdrengen said:

its like the view is made of two circles overlapping(is that a word? im danish so..)

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FYI: "Overlapping" is indeed an English word. However, you used the word "glasses" to refer to "binoculars" in the title of your thread. That is not correct English and confused me. "Glasses" means "eyeglasses" or "spectacles", so I thought you had new eyeglasses and were having problems seeing with them. People on this forum do sometimes use the word "glass" as an informal expression to refer to binoculars, but I have never seen the word "glasses" used until now. Anyway, I hope this makes sense; English is one confusing language, and I am certainly glad I did not have to learn it as a second language!

I am not sure about your problem, but your approach of comparing with other binoculars seems like the best way to determine if there is a problem.

Cheers,
Jim

Title edited ; )
Why did i compare my cheap olympus with that Nikon HG anyway!....



edit: hm, thought i could edit it, but nothing happened..

keithdrengen said:

Its worse when close to an object. Today i went to a store and compared with a Nikon 8x20 High Grade, and it showed the same issue with not overlapping completely( it was better though than my Olympus, maybe because of a wider field of view) so it might be normal.

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I am not sure about this, it may be a collimation error, but what it sounds like is when you look at the circle edges your eyes are at close focus and you are seeing the IPD offset. At far focus, when you are indeed focused far away, the circles appear as a blur and overlap but as soon as you look at the circles your eye shift to close focus and you see the offset again.

The main thing to check for is to pick an object some distance away and make sure you only see one of them. If you see two objects out about 30 m, then I would say, indeed, collimation.

J. Moore said:

..............you used the word "glasses" to refer to "binoculars" in the title of your thread. That is not correct English and confused me..............Cheers,
Jim

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I would be inclined to disagree, Jim...."Field Glasses" is a term for binoculars, perhaps a little archaic nowadays, and sometimes abbreviated to "glasses" as long as the context is understood. :t:

Sancho said:

I would be inclined to disagree, Jim...."Field Glasses" is a term for binoculars, perhaps a little archaic nowadays, and sometimes abbreviated to "glasses" as long as the context is understood. :t:

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OK. Good point. Not only "field glasses", but also "opera glasses". But it definitely confused me. And I think it would typically only be used without the modifier if the modifier had already been used in the discussion--precisely because it would be confusing otherwise.

Best,
Jim

If you have a narrow IPD (that's the distance between your eyes) and your binoculars don't close to that distance, then you will have difficulty seeing a single image and this will get worse as you focus closer.

Michael

Glasses is a perfectly acceptable term for binoculars in "English" English as opposed to "American" English which is often different. LOL.

Thanks replying! I think they are fine, 30 meters out its no problem to get a "single picture".
Cheers from Denmark

keithdrengen said:

Thanks replying! I think they are fine, 30 meters out its no problem to get a "single picture".
Cheers from Denmark

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Okay, but IPD could still be a factor. When you look at close objects your pupils move inwards, so that the IPD that works fine at 30m no longer works at 2m or 3m. As long as it happens only at close range, you don't have a problem. You either adjust the IPD temporarily or put up with the overlapping. Obviously, the smaller the exit pupil, the more this will be a factor.

Michael

(keeping this other problem in same thread),
The oculars easily fogs up when using them inside the house, have yet to test outside.
Any lens-cleaner that can help prevent that? Some window cleaner used in cars, stops fogging.

keithdrengen said:

(keeping this other problem in same thread),
The oculars easily fogs up when using them inside the house, have yet to test outside.
Any lens-cleaner that can help prevent that? Some window cleaner used in cars, stops fogging.

Click to expand...

Hi;
I have never tried these on binoculars, I bought some for the field crews to try with our survey optics and they reported mixed results. They never asked for anymore of them (bought a year or so ago) so I do not know if they are still using the original 3 packs I bought them or just gave up. There does not seem to be much that helps dewpoint fogging. I will ask tomorrow at work.

I do not understand the fogging inside though.

http://www.amazon.com/Nikon-8073-Fog-Eliminator-3-Pack/dp/B0007M6GJ0

Ron

Hi Keith;

Curiosity got the best of me. I took a Nikon Fog Eliminator and rubbed a stripe on the side of a glass and then ran a standard test to measure the dewpoint. The dewpoint calculated to be 47 F and worked out to be very close. I ran the glass temperature down to 35 F and remained fog free. So they seem to be somewhat effective.

Best,
Ron

Thanks for the tip!
When i tried them outdoors the other day there were no fogging though..
When indoors i think its because the heat of my eye(!) makes the ocular fog. The problem decreases when "heating" the binoculars by holding them in my hands, or close to my body. When outside it seemed no problem, because of wind - lowering the impact of my bodyheat. In this particular case its not a problem anymore for ME, because i sent them back the other day..
Happy holidays
Carsten

[its like the view is made of two circles overlapping...eachother almost completely, but NOT completely, only like 95% or more. Is it normal? ]

This is normal. I had this to say in a recent article

"Close Focus
Most of these (42mm roofs) have 6-7ft. close focus. ... With slight variation +/-, they all have only about 70% of the field of view overlapped in binocular vision at 7ft. However, when focused at 20ft., they all have approx. 90% of the field overlapped for binocular vision.

What you really get with these small binoculars when it comes to close focus (assuming at 10ft) is a "binocular vision" field of view about 10 inches wide (at 10 feet). Both the Bushnell Legend 8x42 (6.5° fov) and the 10x42 Regal (6.0°fov) show nearly identical results. At a distance of 10 feet they can see 31-32cm with only 25 cm of that field overlapped, so for binocular vision they see 10 inches out of just over 12 inches. In these same binoculars, when viewing at 100 feet (30m) the barrel overlap is off by less than 5% of the fov and you get a 10 foot wide view with binocular vision while only 6-8 inches is not overlapped."

Out of approx 50 binoculars tested not one has the fov completely overlapped for total binocular vision at close focus. In fact very few have total ovelap even at 100feet. This does not mean the binocular is out of collimation. collimation is the merging of two points in the fov. The overlapping of the fov is a related issue, but unless extremely mis-lapped, not serious.

Typical small roofs are mislapped by 10% at 20feet focus. Typical small porros are mislapped by 20% at 20 feet focus. Both the Nikon SE 12x50 and 10x42 are mislapped by more than 20% when focused at 20 feet, the Nikon SE 8x32 by nearly 20%. You cannot change this by adjusting the IPD. If you can then your binoculars are only conditionally aligned, a less desireable condition.

edz