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Old Tuesday 30th December 2014, 06:29   #1
Saturninus
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Pentax Papilio - Collimation and convergent lenses

Hi All - I'm a bit new to this so bear with me. I just received a Pentax Papilio 6.5x in the mail. They are amazing! But I can't tell if my pair is out of collimation, or if this is just how they are because of the unique focusing system...

I've done the quick test of collimation by focusing on a telephone wire and holding the binoculars about 6 inches away from my eyes to see if the line remains unbroken. Vertical collimation seems fine, but the lateral collimation is either way off...or it's just supposed to be like that? When at close focus settings, I noticed that the fields of view from each eye do not overlap perfectly. For instance, the outer left 20% of the view in the left barrel is not visible in the inner left view of the right barrel, and vice versa. The result is that the together the fields of view from each eye look like that Mastercard symbol - two overlapping circles, not a single merged circle. If I close my left eye, I see a different scene than my right eye. The field of view is shifted left or right by 20%.

And yet, I do not have trouble merging images in the center of the overlapping fields of view. In addition, when focused to infinity, the view is a single circle like you would expect.

This leads me to think that what I am experiencing at close focus is just the effect of the convergent lens system. Either that, or binoculars are going out of alignment at close focus.

Is it the binoculars? Or is it my eyes? Or is this how it is supposed to be? Unfortunately, there are no retailers close to where I live, so I can't look through another pair to compare.
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Old Tuesday 30th December 2014, 15:23   #2
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Welcome Saturninus,
Is the IPD set correctly for your eyes?
Try changing it.
You may need prism correction for your eyes or it could be the binocular.

Iapetus
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Old Tuesday 30th December 2014, 17:20   #3
ceasar
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I was thinking the same thing about the IPD. Saturninus mentioned that every thing looked good at infinity so I assume his IPD was spot on. One usually has to make the IPD more narrow when looking close up in order to get a full circle view.

Papillos are reverse Porro prisms and focus by moving the objective lenses in and out. You change the IPD by moving the ocular lenses on it.

http://www.us.ricoh-imaging.com/spor...!product-specs

Bob

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Old Tuesday 30th December 2014, 17:26   #4
Binastro
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I have the Papilio and it is very nice.
The lens system also tilts as you focus close.
Maybe patented?
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Old Tuesday 30th December 2014, 17:43   #5
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I have the Papilio and it is very nice.
The lens system also tilts as you focus close.
Maybe patented?
Don't know about any patent but if you go to the link above and click on the highlights it says it has a special design technology " that "compensates for misalignment in right and left fields at close range." I had an 8.5x21 that worked well. I used to use them on a friends deck to watch humming birds at his feeders close up. He ended up with them. We usually watched them from 5 to 10 feet.

Bob

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Old Thursday 1st January 2015, 05:14   #6
WJC
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Originally Posted by Saturninus View Post
Hi All - I'm a bit new to this so bear with me. I just received a Pentax Papilio 6.5x in the mail. They are amazing! But I can't tell if my pair is out of collimation, or if this is just how they are because of the unique focusing system...

I've done the quick test of collimation by focusing on a telephone wire and holding the binoculars about 6 inches away from my eyes to see if the line remains unbroken. Vertical collimation seems fine, but the lateral collimation is either way off...or it's just supposed to be like that? When at close focus settings, I noticed that the fields of view from each eye do not overlap perfectly. For instance, the outer left 20% of the view in the left barrel is not visible in the inner left view of the right barrel, and vice versa. The result is that the together the fields of view from each eye look like that Mastercard symbol - two overlapping circles, not a single merged circle. If I close my left eye, I see a different scene than my right eye. The field of view is shifted left or right by 20%.

And yet, I do not have trouble merging images in the center of the overlapping fields of view. In addition, when focused to infinity, the view is a single circle like you would expect.

This leads me to think that what I am experiencing at close focus is just the effect of the convergent lens system. Either that, or binoculars are going out of alignment at close focus.

Is it the binoculars? Or is it my eyes? Or is this how it is supposed to be? Unfortunately, there are no retailers close to where I live, so I can't look through another pair to compare.
When viewing at very close range, you will see the fields overlap. Some folks think the bino is out of collimation. When you see that, you are focusing INSIDE the bino. When you do that, you are crossing you eyes. When you cross your eyes, YOU are out of collimation, NOT the bino.

Bill

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Old Saturday 3rd January 2015, 00:19   #7
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Thanks for that clarification - that makes sense. To me, the experience of looking at something at very close range takes a bit of getting used to. I tried looking at a something on my screen door at minimum focus distance and the indistinct, repetitive pattern of the wire mesh tied my optic nerves into knots. I thought my head was going to explode. I am going to conclude that there is nothing wrong with the collimation.
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Old Saturday 3rd January 2015, 04:48   #8
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Thanks for that clarification - that makes sense. To me, the experience of looking at something at very close range takes a bit of getting used to. I tried looking at a something on my screen door at minimum focus distance and the indistinct, repetitive pattern of the wire mesh tied my optic nerves into knots. I thought my head was going to explode. I am going to conclude that there is nothing wrong with the collimation.
When you look at a DISTANT object--concentrating on the object--and then see the fields overlap, you COULD have a problem. If the distant object (2,000+ yards) provides a double image, you definitely do.

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Old Tuesday 6th January 2015, 20:41   #9
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In my experience using several units of the Pentax Papilio, I can confirm that as WJC noted, both sources of alignment error are possible (and, of course, they aren't mutually exclusive). When using the Papilio and quickly raking the focus, it is possible to get the strange feeling that something isn't collimated, where that something is your own eyes. However, as with any bin, the unit can be out of alignment. From the samples I've seen, alignment accuracy seems to vary as much as it does in other reverse porro compacts at this price point, which is to say quite a lot. The one I own has excellent alignment, but it was the best of five that I tried, the worst of which was grossly off (though not to the point that I couldn't, with discomfort, compensate with my eyes to prevent getting double vision).

--AP
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Old Wednesday 7th January 2015, 05:22   #10
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I checked collimation at infinity using the imprecise method of comparing the distance to the edge of field of a distant point object in each barrel, and it seems to be ok. Not perfect, but within what I generally find tolerable. Having said that, while vertical collimation is easy to get a good idea of, I have a hard time assessing horizontal collimation.

Is it the case that because of the close focus mechanism, errors in horizontal collimation become magnified at close focus distance in the papilio? Or, because of the moving parts, the binoculars might go out of collimation after the lenses move into position for close focus?

I've gotten used to view in the papilio over the past several days. I think when I first starting looking through it, the experience was so novel I didn't know what to make of it. No headaches, and I don't have any trouble merging the view. I'm very happy with it now.
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Old Friday 9th January 2015, 18:50   #11
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Originally Posted by Saturninus View Post
I checked collimation at infinity using the imprecise method of comparing the distance to the edge of field of a distant point object in each barrel, and it seems to be ok. Not perfect, but within what I generally find tolerable. Having said that, while vertical collimation is easy to get a good idea of, I have a hard time assessing horizontal collimation.

Is it the case that because of the close focus mechanism, errors in horizontal collimation become magnified at close focus distance in the papilio? Or, because of the moving parts, the binoculars might go out of collimation after the lenses move into position for close focus?

I've gotten used to view in the papilio over the past several days. I think when I first starting looking through it, the experience was so novel I didn't know what to make of it. No headaches, and I don't have any trouble merging the view. I'm very happy with it now.
Step--dipvergence--is easier to spot because we can accommodate far less separation in the vertical axis.

Bill
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Old Saturday 10th January 2015, 16:52   #12
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From the samples I've seen, alignment accuracy seems to vary as much as it does in other reverse porro compacts at this price point, which is to say quite a lot.

--AP
Hi Alex

I had a look through my uncle's Papillio last year and was horrifed at how bad the collimation was. My uncle hadn't noticed because he only has vision in one eye.

Lee
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Old Sunday 22nd March 2015, 15:57   #13
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When I bought mine I tested them out first and ran into one bad pair out of three that just did not focus properly. I bought the 6.5x because the coatings aren't the best and I thought the 8's were too dim.

So now I have 2 pairs of the 6.5x that collimate and focus perfectly. One pair I never took out of the box when I got it home from the store. Was going to give it as a gift but now I'm just going to sell them.
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Old Wednesday 8th April 2015, 03:06   #14
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I find it easier to check collimation if I look at a distant point. There's a small piece of something, 2-3 inches in diameter, on a telephone pole about 125-150 yds away. If I can relax my eyes and look at that, that seems to make it easier to pick up how far off it is, more easily than wires or tree branches

A bobber in a tree or streetlight or distant mailbox works, too.

Probably not 100%, but seems like a pretty good way to check.
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Old Saturday 11th April 2015, 01:57   #15
WJC
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I find it easier to check collimation if I look at a distant point. There's a small piece of something, 2-3 inches in diameter, on a telephone pole about 125-150 yds away. If I can relax my eyes and look at that, that seems to make it easier to pick up how far off it is, more easily than wires or tree branches

A bobber in a tree or streetlight or distant mailbox works, too.

Probably not 100%, but seems like a pretty good way to check.
Hi your Redness:

"125-150 yards" is too close to get the FULL benefit of the alignment. When you get it good enough at that distance, your spatial accommodation will take over and do the rest for you--close, but no C-gar.

I've said what I've said to be TECHNICALLY accurate. If it works good enough for you, don't worry about it; just have fun.

Some folks are too into semantics and academics to have any fun. 'Pity, really!

Bill
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