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Is it Phase Coated?

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#1 bananas

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Posted 14 October 2019 - 11:48 PM

My binocular is advertised to be phase coated.  When I did the polarizer test by using my computer monitor and a lens polarizer I can see the split in the field of view.  One half changes colors from blue, green, pink and then it switches to the other half.  Are the prisms truly phase coated?



#2 TOMDEY

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Posted 15 October 2019 - 12:24 AM

I just read up on it... their literature... sure looks like old fashioned marketing mumbo-jumbo pseudotech to me. Probably no more or less than trademark/tradename mystique.   Tom



#3 sg6

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Posted 15 October 2019 - 02:43 AM

What are the binoculars?

Only applicable to roof prism binoculars.


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#4 Rich V.

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Posted 15 October 2019 - 11:30 AM

My binocular is advertised to be phase coated.  When I did the polarizer test by using my computer monitor and a lens polarizer I can see the split in the field of view.  One half changes colors from blue, green, pink and then it switches to the other half.  Are the prisms truly phase coated?

Doing the above "test" with binos I know to be phase coated, I see the same results.  It's much easier to see the roof edge if you point the eyepieces towards the screen and look into the objectives through the polarized filter.  You can turn the binos or the polarizing filter to see the "spit screen" effect.

 

https://www.birdforu...84&postcount=16

 

I wish I has some non- PC binos to compare results with.  I'd be interested if anyone has both PC and non-PC binos to compare this way just to see what difference may show up.

 

Rich


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#5 Pinac

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Posted 15 October 2019 - 02:16 PM

.....

.....

..... I'd be interested if anyone has both PC and non-PC binos to compare this way just to see what difference may show up.

 

.....

I do.

Most of the better ones are of course phase coated today, but e.g. the Docter 7x40 is a well-known exception, at least to my knowledge.

I know the physics involved, but have never done the test myself. Also not sure how strong any effect will be with 7x binos, the effect seems much more felt with 8x, 10x or more.

Let me try sometime this or next week and report back.


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#6 FrankL

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Posted 15 October 2019 - 08:48 PM

"I'd be interested if anyone has both PC and non-PC binos to compare this way just to see what difference may show up."

 

If non-phase coated about 1/2 of the view is white or off-white and the other half is black, grey or dark brown. There aren't any blues, reds, greens, pinks etc. Attached in the view from a WW II bmj (Hensoldt) Dienstglas (militarized version of Dialyt) 7x56 having a non-phase coated A-K prism.

Attached Thumbnails

  • bmj 7x56 5 (469x460).jpg

Edited by FrankL, 16 October 2019 - 09:12 AM.

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#7 Foss

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Posted 16 October 2019 - 09:29 AM

Hi Frank,

Can't quite figure out what the image shows. Is it a prism edge photo taken thru and objective?

Thanks,

Jack



#8 FrankL

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Posted 16 October 2019 - 10:30 AM

Hi Frank,

Can't quite figure out what the image shows. Is it a prism edge photo taken thru and objective?

Thanks,

Jack

The photograph was taken through 3-D movie glasses through the objective lens with the binocular eyelens facing a computer monitor screen having a white background.The dividing line between the two colors is the roof edge of the roof prism.


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#9 bananas

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Posted 16 October 2019 - 04:12 PM

phase-coating.gif

 

 

 

Hopefully you can see this animated gif.   The polarizer coating on my sunglasses are uneven so I used a camera lens polarizer to make a more uniform color rendition.  The colors are much more saturated when viewed with my own eyes.  The bino eye piece is about four inches away from the monitor screen and the camera is four inches away from the objective lens.  I'm rotating the polarizer.


Edited by bananas, 16 October 2019 - 04:15 PM.

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#10 Rich V.

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Posted 16 October 2019 - 04:42 PM

Well, I'd say they were PC based on the colors seen and examples shown.  I also used a camera polarizing filter when inspecting my PC roof binos and the colors seem similar to your example.



#11 FrankL

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Posted 16 October 2019 - 05:00 PM

Looks like they're phase coated. Note that although phase coated prisms will show an array of  colors when viewed through polarizers, the colors and arrangements of them can differ from one model of phase coated roof prism binocular to another. This is due, I imagine, to different types and most likely varying qualities of phase coatings. 


Edited by FrankL, 16 October 2019 - 05:01 PM.


#12 Rich V.

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Posted 16 October 2019 - 08:11 PM

It's interesting, though, that roof prisms create variable wavelength polarization effects even if they are phase coated.  Wouldn't that suggest that some phase interference exists between the two roof faces?  Is there a way to quantify the visual effect?

 

I compared one of my Nikon Porros with the Pentax roofs mentioned above and as you'd expect, no effects seen.

 

Rich



#13 bananas

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Posted 16 October 2019 - 09:42 PM

I just did the same test to my Olympus WP I 8x25 and a generic 8x42.  Neither of them were listed to be phase coated.  They both showed similar changing color patterns as my first binoculars.  So now I'm confused.  What are the chances that the Chinese will apply a phase coating to a $30 binoculars and not tell me about it?   Perhaps this is  not a good test after all.



#14 Pinac

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Posted 18 October 2019 - 05:00 AM

Here is my take on the subject, after playing around with a number of instruments, for whatever it's worth:

 

 

1. The colors as such are not a reliable indicator whether or not a binocular is phase coated. As mentioned by FrankL, even between non-phase coated ones, they change from bino to bino (e.g.: my 1950s Hensoldt Dialyt 8x56 shows very different colors, more in the blue, than the ones shown in post 6 above).

 

2. Binos WITHOUT phase coating show mainly two colors, always separated by a sharp diagonal line. Most of my glasses display colors in the blue area of the spectrum. When rotating the filter (or the bino), the colors can change a bit in tone and will "switch places" during the turn. But there always remains a sharp separation between the two halfs of the image, and the type of color displayed remains more or less the same.

 

3. Binos WITH phase coating display a variable array of colors, many more than two, when rotating the filter or the bino, and in addition, the colors change in intensity. The separating diagonal line can at some point in the rotation almost completely disappear and reappear upon further turning. Every binocular exhibits its own characteristic pattern. I am sure that with further study and practice, we can learn to assess not only the presence, but also the quality of the phase coating.

 

Is the above in line with what other forum members are seeing?

 

 

Thanks to all posters in this thread for their contributions and for bringing up the subject. I had not done this test before and will now complete the specs of my binocular collection accordingly.

 

Pinac


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#15 mooreorless

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Posted 18 October 2019 - 06:46 AM

Here is a link from BF of difference between with phase-coating and with out phase coating.  I hope Mods do not mind the link.

https://www.birdforu...88&postcount=19


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#16 FrankL

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Posted 19 October 2019 - 07:12 AM

“Is the above in line with what other forum members are seeing?”

 

Pinac, this is a perfect description of what I have also seen testing about 6 or 7 binoculars both phase coated and non-phase coated. 

 

Interesting that not all makers of binoculars will label them as phase coated even if the are. I suppose this is because phase coating may now almost 30 years after introduction have become an industry standard.



#17 j.gardavsky

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Posted 19 October 2019 - 08:46 AM

I have right now made the test, both with the linear pol filter, and with the linear/circular pol filter, on my Leica Ultravid 7x42 (Schmidt-Pechan roof prism), and on my  Swarovski EL Swarovision 8.5x42 (Abbe-König roof prisms).

Just nothing, no split line visible, no colors.

 

It looks like, there is a difference on what the marketings understand, or let us believe, about the phase coatings on the roofs.

 

JG


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#18 bananas

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Posted 10 November 2019 - 10:41 PM

I did another polarizer test but this time I was standing eight feet from the binoculars holding the filter.  This time the split was not visible and the color transitions appeared to occur throughout the surface area like a smooth gradient.



#19 j.gardavsky

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Posted Yesterday, 04:34 PM

No colors in the polarization filter test on the leica Ultravid 7x42,

and very faint colors on the Swarovski 8.5x42 EL Swarovision.

No split line in the both, either.

 

Best,

JG



#20 MartinPond

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Posted Yesterday, 08:47 PM

A note on monitors:

 

----The entry referenced was from 2012, when polarization was

    still commonly used to control the brightness

 

-----For some time now, TV/PC/Laptop displays have been

     a matrix of tiny LEDs.....that do NOT rely on polarization.

 

Your results will vary widely and by chance, at best.

They will be...uninspired in ~2015 and beyond.

There were also "twist" and "supertwist" displays before...

   ...those act differently from each other.

 

There is also an awkward conflation of

    polarization and phase coating there...they are not the same

   or related effects.


Edited by MartinPond, Yesterday, 08:47 PM.


#21 MartinPond

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Posted Yesterday, 08:54 PM

A better way to see if there is phase coating on

 roof prisms:

---mount the binoculars somehow, with a star

   or stars in the middle of the field

---(the tricky bit) put a 4-7x monocular on the 

  eyepiece (both focused to infinity, focus binocs

   again for the monoc)..

----the stars will show a spike sprouting out on 

    just one axis (usually vertical)..

   .....if:   there is no phase coating

   ....or if:  the angles were not precisely ground (even if phase-coated)

 

Baader makes an Amici (the heart of the roof prism)

  that is precise enough to avoid any spiking.

It is not cheap though!

https://agenaastro.c...x1-2456130.html


Edited by MartinPond, Yesterday, 08:56 PM.



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