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Misaligned Pentax 20x60 PCF WP II ?

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#1 Jarrod

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Posted 30 January 2013 - 04:01 PM

B&H just delivered. Unpacked the binos and wow, these are well built. Adjust the diopter, achieve focus, and no merging of the circles at MFD. Drat!

At 27 feet, the right tube points 5" to the right of the left tube. If I did my trig right, that means it's .88 degrees off.

Return them for a new set?

#2 BillC

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Posted 30 January 2013 - 04:06 PM

Oh, I've seen people happy with much worse than that! As A matter of fact, I'm selling some Ocean Front property just west of Ellsworth, Kansas to one of those guys, this week!

Send'em back; you shouldn't have to deal with that, especially on THAT bino.

BillC

#3 Jarrod

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Posted 30 January 2013 - 04:23 PM

Thanks. Yeah if I look at something far away I can merge the images reasonably well. Not sure I'd really have noticed in that case. But yeah, this set is kind of useless for watching birds in the back yard.

Now that I'm paying attention, my Leupold 8x50s are not perfectly aligned either. Probably also 4-5" at 27 feet. But I can merge it at the closer distances for some reason. Is it just the lower magnification? The bigger exit pupil?

I'm going to ask a dumb question. If you close the right eye, look through the left tube at an object, then look through the right tube and close the left eye, should the image be exactly the same if the binos are properly setup? Or is there supposed to be some separation, so your brain gets stereo?

#4 ronharper

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Posted 30 January 2013 - 04:35 PM

The right barrel should point to a place a few inches to the right of the left barrel if they are parallel, that distance being simply the distance between the centers of the objectives. 5" sounds pretty reasonable, measure your objective spacing and compare.

Not saying you don't have a collimation problem! This distance thing is just not a good test for that, is all. Normal use will tell that much better.
Ron

#5 BillC

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Posted 30 January 2013 - 05:00 PM

Thanks. Yeah if I look at something far away I can merge the images reasonably well. Not sure I'd really have noticed in that case. But yeah, this set is kind of useless for watching birds in the back yard.

Now that I'm paying attention, my Leupold 8x50s are not perfectly aligned either. Probably also 4-5" at 27 feet. But I can merge it at the closer distances for some reason. Is it just the lower magnification? The bigger exit pupil?

I'm going to ask a dumb question. If you close the right eye, look through the left tube at an object, then look through the right tube and close the left eye, should the image be exactly the same if the binos are properly setup? Or is there supposed to be some separation, so your brain gets stereo?


IF you can switch fast enough and
IF you were not allowing your Spatial Accommodation to get involved in the first place. Don't feel bad; I GUESStimate that that more than 80% of bino users are using instruments that are out of alignment, many of whom don't know binos NEED to be aligned.

BillC

#6 Jarrod

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Posted 30 January 2013 - 05:07 PM

OK, let me do a better job describing what I'm seeing, without jumping to any conclusions. Bear with me - I've never had anything more than an 8-power binocular...

When I'm focused on something at or near the MFD (25-40 feet or so), my brain *can* merge the two images. But I don't see a single circle, I see the "binocular mask" shape thingy that they use in movies to show that someone is looking through binoculars. So I see a stereo image in the center, plus partial left- and right-eye images on the left and right edges of the view. When I look at something farther away, I see a single circle - stereo from edge-to-edge. The view is perhaps ever so slightly oblong, or it could be my imagination...

Until today, I've never even thought about the fact that binoculars, unlike eyeballs, cannot change the point in space where they converge. So it makes intuitive sense to me that such artifacts could be possible. But I have no idea how 20x binocs are really supposed to behave in this regard.

And yes, the objectives are about 4.5" apart when set to my IPD of ~60mm. Which is the offset I measure between the left and right eye images when I alternately close my left and right eyes while fixed on an object 27' away.

#7 BillC

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Posted 30 January 2013 - 05:12 PM

"When I'm focused on something at or near the MFD (25-40 feet or so), my brain *can* merge the two images. But I don't see a single circle, I see the "binocular mask" shape thingy that they use in movies to show that someone is looking through binoculars."

At "25-40 feet" you are STILL crossing your eyes a little. And when you do, you will see that "'binocular mask' shape thingy that they use in movies." It's just optics doing what optics do.

Now look at a small target a mile or more away. If your bino is near collimation, the field stops wont be obtrusive.

BillC

#8 Jarrod

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Posted 30 January 2013 - 06:24 PM

Someone just clued me in to the term "Master Card effect". That is what I'm seeing. I have never seen that with a pair of binoculars before, but I have never critically looked through anything more than a 10x before today. It's getting dark and the weather is nasty. More looking tomorrow.

#9 BobinKy

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Posted 30 January 2013 - 06:31 PM

Return them for a new set?


Yes, do it tomorrow, without delay.

#10 Jarrod

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Posted 30 January 2013 - 06:33 PM

Bob! So I take it from that comment you don't see the master card effect in your set, when viewing objects within 40-50' of you?

#11 BillC

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Posted 30 January 2013 - 06:48 PM

Bob:

Did you say anything about that, or simply suggest that Jarrod return the bino?

Jarrod:

You're welcome to reinvent the wheel all you want. However, the optical wisdom gained over that last 400 years suggest that you pick a REALISTIC distance--6,000+ feet and not 40 to 50. It DOES make a difference!

BillC

#12 BillC

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Posted 30 January 2013 - 06:48 PM

Bob:

Did you say anything about that, or simply suggest that Jarrod return the bino?

Jarrod:

You're welcome to reinvent the wheel all you want. However, the optical wisdom gained over that last 400 years suggests that you pick a more REALISTIC distance--6,000+ feet and not 40 to 50. It DOES make a difference!

BillC

#13 hallelujah

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Posted 30 January 2013 - 07:03 PM

Someone just clued me in to the term "Master Card effect". That is what I'm seeing. I have never seen that with a pair of binoculars before, but I have never critically looked through anything more than a 10x before today.


It is noticable with my Pentax PCF WP 20x as well as my Pentax PCF WP II 20x.
Not as exaggerated with my Pentax PCF WP 16x60.

Very noticable with my Minox 10x44 Porro.

I experience it when focusing at the closest distances.

http://www.google.co...epad.com/.a/...

Stan

#14 Jarrod

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Posted 30 January 2013 - 07:32 PM

Not trying to reinvent the wheel. I'm sure these things are obvious to an expert but I am just trying to understand if what I'm seeing with this set is because of optics "doing what they do", or some alignment issue. Bob has this same set so I was curious if he noticed it as well.

I will do as you suggest when there is daylight and it isn't raining out. The furthest thing I can see from my window is less than 100 yards away, and although the effect is much reduced at that distance I don't believe it is completely gone.

#15 Jawaid I. Abbasi

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Posted 30 January 2013 - 07:32 PM

This is normal if viewing less then suggested. For a close look; buy Pentax papelio and you will nôt see the effect.

It seems to me that the error is within the 150"-200" (correct me if I am wrong)

#16 Jarrod

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Posted 30 January 2013 - 07:42 PM

Thanks for confirmation Stan. Jawaid, yes I think you are right - the furthest I was able to look with these today was about 200' at most and while the effect was greatly reduced it isn't 100% gone at that distance. It sounds like this is the norm for this model and I simply shouldn't plan to bird with it in my backyard.

That's OK, I put the Canon 10x30 IS on my Amazon wishlist today :grin:

#17 hallelujah

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Posted 30 January 2013 - 07:52 PM

Thanks for confirmation Stan.

It sounds like this is the norm for this model and I simply shouldn't plan to bird with it in my backyard.


I have used my Pentax 20x60, for birdwatching, from my backyard, for many years;
maximum focusing distance, within my backyard, is approx. 60'.

I have no problems with the views.

Stan

#18 BillC

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Posted 30 January 2013 - 07:57 PM

"the furthest I was able to look with these today was about 200' at most and while the effect was greatly reduced it isn't 100% gone at that distance."

So, if it is REDUCED at THAT distance, there's probably a chance that objects seen at more than a mile will be right on. And, if they're right on with you just staring, you're good to go. Many a problem has had it's origin in ill-formed opinion.

Good luck and happy viewing!

BillC

#19 Jarrod

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Posted 30 January 2013 - 08:33 PM

I have used my Pentax 20x60, for birdwatching, from my backyard, for many years;
maximum focusing distance, within my backyard, is approx. 60'.

I have no problems with the views.


Now that you mention it, I was clearly reading 12 point helvetica from 27' across the house, with the master card effect. I guess I could just ignore it. But then this removes an excuse to get the Canons :grin:

Many a problem has had it's origin in ill-formed opinion.


Yes indeed. :foreheadslap:

#20 GlennLeDrew

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Posted 30 January 2013 - 09:55 PM

Binoculars are (normally) axially aligned so as to be parallel at infinity. At close distances, parallax causes the image displacement you noted. This is perfectly normal.

Do not return until you verify collimation for a *very* distant target!

#21 Rich V.

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Posted 30 January 2013 - 11:03 PM

Jarrod, I'd be more concerned about the alignment when the binocular focused at infinity. That's the reference the binos are aligned to.

As you focus on closer targets, your eyes must cross a little to merge each image to adjust for parallax, the closer, the more so. That happens with all binoculars; some more than others by design.

Do you see stars or the Moon double when you first put the binos up to your eye? Your eyes should be able to relax "just as if you were gazing out into space". No crossing or straining! ;)

If you still feel you're straining to keep a merged image, don't hesitate to send them back.

Rich

#22 BobinKy

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Posted 30 January 2013 - 11:57 PM

Jarrod...

If I am not mistaken, you bought the Pentax 20x60 for viewing the night sky. Why not wait until you have a clear night and begin with viewing a bright star, planet, or the Moon. Then decide if you like the view.

To answer your question about the mastercard effect on close focusing--with the Pentax 20x60 I really do not remember, as I am always looking at targets 1000 yards away or in the night sky. If Stan says he sees the mastercard effect with his Pentax 20x60 and other binoculars at close focus, then that is good enough for me. The effect must be there--I have just not paid any attention to it. I guess I am more concerned about what I see than how I see it.

Relax and enjoy. You have 30 days for the trial period. And B&H Photo is an excellent online vendor who will work with you. You can also contact Pentax and ask them a few questions. Here is the link for Pentax Sports Optics: Customer Support. Remember Pentax has a very nice "Worry Free" warranty on their products. :)

Best of luck.

#23 Man in a Tub

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Posted 31 January 2013 - 12:39 AM

About three years ago, I received a query about this effect from a member who had just bought a Brunton Eterna 15x51. I had never thought to focus my 15-power Brunton inside my apartment. Sure enough, it was just like in the movies, and unlike my Celestron Skymaster 20x80 at the time, the Brunton was (and remains) collimated.

Using a high-power binocular for close viewing strikes me as almost the inverse of wanting fantastic views of planets — that is, a similar misuse with inevitable frustration.

#24 hallelujah

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Posted 31 January 2013 - 01:24 AM

Using a high-power binocular for close viewing strikes me as almost the inverse of wanting fantastic views of planets — that is, a similar misuse with inevitable frustration.


Todd,

Well shucks, I use more than one 20x binocular, close up, for backyard viewing of birds & squirrels and such.

I have yet to reach the point of frustration. :doah:

Thanks for pointing it out, now I know what I have been missing all these years. :lol:

BTW, if I want Fantastic Views of the Planets, with my 20x binoculars, I'll just hang one of my astronomy books
on my fenceline & view it from approx. 35'-40' away. :p

Stan

#25 Jarrod

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Posted 06 February 2013 - 08:04 PM

My p-mount arrived today (hurray) and there is some sky to look at tonight, so I was finally able to take these out for a look.

Junk. My initial reaction last week was correct. I saw two jupiters, partially overlapping, diagonally (so, very close together). But if I then defocus the right tube, the two jupiters snap FAR APART. A bit more than half the radius of the FOV, so somewhere between 0.5 degrees and a degree. If I then refocus the diopter while still viewing they *almost* snap back together. Amazing what the brain tries to do for you....

Back they go for another set. Wish me better luck this time.






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