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Semi-apo v fully apo binoculars

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#1 25585

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Posted 27 May 2019 - 08:54 AM

How much in the field, real life (not lab), difference is there between semi-apo and fully apo binoculars, at the magnifications used for, and views with binoculars.

 

Are semis worth the $aving?   



#2 Beg

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Posted 27 May 2019 - 09:24 AM

In real life between my Oberwerk ED and my Orion SA, the difference is that the image is "cleaner". Bright stars focus to a sharper point as CA is basically eliminated in the ED. You get truer star colors. The same is true for planetary. A sharper cleaner image. The moon is more pleasant as all fringing is eliminated. True colors. And all of this kind of heightens the illusion of contrast enhancement. 

On sweeping the MW for clusters and nebula they are more or less the same. 

 

So cleanliness costs $1000 in a 100mm. As a lifetime investment in a nice Binocular the ED is worth it.....


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#3 coopman

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Posted 27 May 2019 - 10:49 AM

It only hurts once when buying good optics.  If you settle for less, the lingering guilt for not doing so in the first place will eat away at your soul and you'll eventually go mad.


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#4 garret

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Posted 27 May 2019 - 01:29 PM

You may have a 100% color free (APO) objective in the front, but if you want zero lateral color you still need a excellent eyepiece in the back.

Typical binoculars operate at very fast Focal Ratio, about F4.5... APM 100, 120, and the 100mm Oberwerk  operate at F5.5


Edited by garret, 27 May 2019 - 01:34 PM.

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#5 harbinjer

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Posted 27 May 2019 - 02:02 PM

It only hurts once when buying good optics.  If you settle for less, the lingering guilt for not doing so in the first place will eat away at your soul and you'll eventually go mad.

Some people can go with "good enough is good enough".  What if the image was such a small difference you could only see it when looking for it, and only once you've seen it.  You know yourself, and whether good enough will do or will you always wish you had spent more for a small improvement.


Edited by harbinjer, 27 May 2019 - 02:11 PM.


#6 edwincjones

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Posted 29 May 2019 - 04:43 AM

generally I would agree with the above

but sometimes--- it depends

 

fuji 70mm clones vs fujinons vs nikon 70mms

$400 vs 2x  vs 4x

old fujinon 150s

MT $5000 vs EDs 2x vs ED45s 3x

 

If you have the money to spend-sure

but maybe better to spend the extra money on astro trips

or rent/food

 

question.gif

 

edj


Edited by edwincjones, 29 May 2019 - 04:46 AM.


#7 ihf

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Posted 29 May 2019 - 10:26 AM

Are "ED" fully APO - or does one need "SD"? And what comes after "SD"? At some point physics imposes diminishing returns. How close are we to the limit? How much better can binoculars get? Wil we see improvements with high magnification, angle of view, ghost images, weight, stability, price, ...



#8 fdudu

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Posted 26 December 2019 - 06:35 AM

Hello,

 

I ask myself the question indeed.

It is true that I would prefer to buy APO but the price is above my guilt possibilities :)

 

Maybe we could have images that would show the difference between achromatic binoculars called "semi-apo" and apochromatic called "ED" or "SD"?

 

Good heaven

fdudu


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#9 rockethead26

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Posted 26 December 2019 - 09:25 AM

I bought the APM 100 90° Semi-Apo bino in 2013 (the new gray one) and never looked back. About 80% of the time I have the APM UFF 18mm eyepieces parked in it. I have never wished that I bought the Apo version and I have certainly never felt guilty for not doing so. I bought mine for sweeping the Milky Way and gazing at star clusters. I'm glad I left the additional $1000 in the bank. I am a "good enough" optics person.


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#10 garret

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Posted 26 December 2019 - 11:51 AM

Are "ED" fully APO - or does one need "SD"? And what comes after "SD"? At some point physics imposes diminishing returns. How close are we to the limit? How much better can binoculars get? Wil we see improvements with high magnification, angle of view, ghost images, weight, stability, price, ...

APM ED APO binocular telescope = 98% visible color aberration free objective at perfect focus when the sky is very stable. 

I have @110x with my 100 ED yet to see any Color Aberration on stars and planets, on the moon is negligible (Bortle 6 sky) except CA from the eyepiece.

The SD versions has better CA and most likely better Spherical Aberration too, makes 1+1: a optical better binocular telescope, worth the price.

 

 

what come after SD?

In the refractor forum there is topic about the new Zeiss Jena APQ 150/ 1200 fluorite/ quadruplet. https://www.cloudyni...rom-the-grave/ 

This is what comes two or three steps after SD, its yours for nearly Euro 20.000.= excluding any tax.



#11 GamesForOne

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Posted 26 December 2019 - 12:14 PM

Hello,

 

I ask myself the question indeed.

It is true that I would prefer to buy APO but the price is above my guilt possibilities smile.gif

 

Maybe we could have images that would show the difference between achromatic binoculars called "semi-apo" and apochromatic called "ED" or "SD"?

 

Good heaven

fdudu

Images have been posted in various threads. Here is a comparison I took some time ago of the ED version vs. the semi-APO:

 

https://www.cloudyni...74263616528.jpg

 

The difference looks pretty obvious to me and it was plainly obvious visually as well. The SD, from the pics I've seen, improve further from the ED APO, however I still saw some slight color scatter even with the SD in the pics I recall. I can't find a link at this time.

 

The last 10% of improvement always costs you more than 10% increase in price.  wink.gif

 

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Michael Mc


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#12 Moravianus

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Posted 26 December 2019 - 11:49 PM

For me in APM 120 (SD), there is still a weak violet halo around bright stars. How to differentiate if this is from the ocular (Morpheus)?



#13 Binojunky

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Posted 27 December 2019 - 12:26 PM

The area of binocular description has become a minefield with descriptions of HD for high definition, ED glass and special coatings to improve optical performance, this is what I have found, some non ED instruments perform better than those with ED glass or HD glass both in sharpness and controlling the dreaded purple fringing or CA that seems to sway purchasers.  With millions of pairs manufactured every year from many different countries unit to unit variation is another factor that can effect the purchase, if possible the old advice try before you buy still rings true,JMTCW,D.


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#14 25585

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Posted 28 December 2019 - 08:53 AM

Do APM ED apo binoculars use superior prisms to the semis?



#15 Mr. Bill

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Posted 28 December 2019 - 12:17 PM

Besides the differences in glass, there is also the question about level of lens polishing and QC that may account for some of the price difference between achro and apo units.


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