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APM 20x80 ED and Oberwerk 20x65 ED

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41 replies to this topic

#26 ckwastro

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Posted 09 July 2021 - 12:25 PM

Cancri,

 

see

https://binocular.ch...0x65-ed-deluxe/

in particular the section under „Image brightness“

Pinac

One other item on the 20x65 ED. I own a pair myself and love them. I was wondering if the units you tested had the threaded eyepieces for filter use? I noticed you measured the eye-relief at 11.5mm, so wanted to give an update. 

 

Before I bought mine I had talked to Kevin about this, because I wear glasses for observing. He told me they no longer use those threaded eyepieces, and sure enough mine do not have them. Unfortunately I don’t have a Dynameter, but I can attest that the eye relief is now much closer to the stated 18mm, as I have no problem seeing the entire 65* AFOV with my glasses on. 15mm is about my minimum for this so it’s at least up to that now for usable ER, and seems even a bit more to me. 


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#27 Fiske

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Posted 09 July 2021 - 12:41 PM

One other item on the 20x65 ED. I own a pair myself and love them. I was wondering if the units you tested had the threaded eyepieces for filter use? I noticed you measured the eye-relief at 11.5mm, so wanted to give an update. 

 

Before I bought mine I had talked to Kevin about this, because I wear glasses for observing. He told me they no longer use those threaded eyepieces, and sure enough mine do not have them. Unfortunately I don’t have a Dynameter, but I can attest that the eye relief is now much closer to the stated 18mm, as I have no problem seeing the entire 65* AFOV with my glasses on. 15mm is about my minimum for this so it’s at least up to that now for usable ER, and seems even a bit more to me. 

Same here on the 20x65ED eye relief with glasses. Comfortable for me. And with the 25x100 too. I converted my 25x100 Deluxe with parts provided by Kevin, removing the threaded eyepiece covers and replacing them with the same covers on the 20x65ED.


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#28 cbullock

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Posted 09 July 2021 - 02:31 PM

I looked through the objective lenses at a very bright light place just inches from the eyepieces and saw no hazing or fogging of any kind. So that could indicate that the binos are fine. Maybe I just have too critical of an eye or maybe the problem is with my eyes?
From what I hear from you all here is the OB 20x65 is a really fine instrument for the cost! Being financially challenged as I am those could be the right solution for my next bino. I have a Bogen 3020 tripod with a fluid head and mounting system that works well with my smaller bino's but not sure if they would we stable enough for the heavier bino's.
Always feel grateful for the generous nature of you all. Makes it a pleasure visiting here. Kind of feels like hanging spending time with friends!

Chris

#29 Fiske

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Posted 09 July 2021 - 03:03 PM

Chris,

 

Great news on your 12x50 SE. waytogo.gif

 

I'm not sure what binoculars you already own, but for dedicated astronomy use you might consider either the OB 15x70 Deluxe or Ultra. Both less expensive than the 20x65ED and a significant step up from the 12x50 SE -- which is an excellent instrument, of course. Somehow a 15x70 binocular is particularly pleasing. I often use the 15x70 Ultra on a light Bogen tripod for which it is well suited. I haven't evaluated the 15x70 Deluxe, but have heard good reports about it in this forum.

 

Also, you might reach out to Kevin Busarow at Oberwerk about which binocular to choose. He is helpful and a source of good advice.

 

Fiske


Edited by Fiske, 09 July 2021 - 03:52 PM.


#30 ECP M42

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Posted 09 July 2021 - 05:02 PM

Hi jprideaux, I always like to read your posts and see your beautiful photos. Thank you!

 

Yes ED glass will help reduce light spikes and halos on bright objects. With refractors, there are three ways to improve the problems that not all light is focused at exactly the same place.

1. Use higher price specialty glass (ED). There are also different grades of ED glass.
2. Use a triplet (or 4 element petzval) design either with higher cost
3. Use a longer focal ratio (makes it physically longer) 

In reality, ED lenses do not reduce "light spikes and halos on bright objects" (if that's what I can understand), but helps reduce lateral (or radial) chromatic aberrations. 

 

So, only solution 1. is functional for what cbullock required.
The solution 3. it is not functional and indeed, the lengthening of the focal tends to increase the radial CAs, exactly as happens increasing the field of view.

The solution 2. only works if at least three different types of glass are used and nowadays it is much cheaper to use the ED lenses. 

 

So, I'd say only the OB20x65ED or APM20x80ED (or other 20xEDs) would be a leap forward from the 12x50SE. 


Edited by ECP M42, 10 July 2021 - 03:17 AM.


#31 SMark

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Posted 09 July 2021 - 08:06 PM

The solution 3. it is not functional and indeed, the lengthening of the focal tends to increase the radial CAs, exactly as happens increasing the field of view.

So... Lengthening the focal length increases chromatic aberration... 

 

Are you really trying to say that?


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#32 lookoutmtn17

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Posted 09 July 2021 - 08:50 PM

The view of the moon on a black velvet background through the OB 20x65ED is one of the most pleasurable views I have ever had through a binocular. As mentioned by others, I am able to observe the gap between Saturn and its rings on nights of steady seeing, and Jupiter and its moons are always a crowd pleaser. Terrestrial viewing of birds and wildlife works very well, as long as the binoculars are properly mounted on a sturdy tripod with a good quality head. Subtle details of feathers and eyes, along with color variations are excellent. The eye relief with glasses is adequate, once I roll down the rubber eye guards and slightly press my glasses to the eyepieces. At the end of the day, I consider the OB's to be very good to excellent binoculars and would purchase them again. Tim


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#33 cbullock

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Posted 10 July 2021 - 01:42 AM

Once again so much appreciation for all who offer their expertise born of experience! I will need to ponder the choices. What is it about binoculars that makes them so very addicting? There is something quite amazing about optics, especially high quality optics!

Chris
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#34 ECP M42

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Posted 10 July 2021 - 03:13 AM

Hi, SMark. 

 

So... Lengthening the focal length increases chromatic aberration... 

 

Are you really trying to say that?

You must not confuse Longitudinal CA with Transversal (or radial) CA:

[...] lateral chromatism is off-axis aberration, caused by variation of refraction power [...] 

 

At the same aperture, increasing the focal ratio does not correct the TCA, but increases the focal length, which increases the thickness of the lens, which increases the TCA (albeit in minimal proportions).

 

Lateral color error

 

 



#35 Fiske

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Posted 10 July 2021 - 07:17 AM

Once again so much appreciation for all who offer their expertise born of experience! I will need to ponder the choices. What is it about binoculars that makes them so very addicting? There is something quite amazing about optics, especially high quality optics!

Chris

Good question, Chris. I have done astronomy with telescopes for many years and enjoy it. But to me telescopes are not nearly so fascinating nor so compelling as binoculars. Compact marvels of optical and mechanical engineering capable of showing us so much that is hidden in the heavens. Self-contained. Rarely requiring adjustment or anything other than occasional cleaning. Fine companions for questing the night sky. smile.gif

 

Fiske


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#36 Cancri

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Posted 19 July 2021 - 09:30 PM

Thank you all for the replies. It was a very interesting read and a tough decision.

Eventually I decided for the APM and received it today and what do you know... they sent me the cheaper non-Magnesium version that APM sold for some time, with an identical body as the Orion GiantView ED (see thread about it). That was unexpected.

Not a bad binoculars per se. I took a look and the FOV is really great, but the magnification. Let's say I wondered if the 25x100 Model would not be a "better" choice for deep space astronomy (planets, nebulas, etc.)?


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#37 MT4

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Posted 19 July 2021 - 09:40 PM

So if I read that right, you ordered an APM 20x80 ED and they sent you a non-ED one that is 230 EUR cheaper?

https://www.apm-tele...ulars-80mm.html



#38 dufay

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Posted 20 July 2021 - 12:42 AM

So if I read that right, you ordered an APM 20x80 ED and they sent you a non-ED one that is 230 EUR cheaper?

https://www.apm-tele...ulars-80mm.html

 

The binocular Cancri is referring to is no longer shown on the APM page. It appears to have been discontinued. It is a much cheaper binocular than the non-ED MS, more like 300 EUR if I remember correctly.



#39 Rich V.

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Posted 20 July 2021 - 12:59 AM

Hopefully, Cancri was billed for the lower priced LW model, not the higher quality MS ED.



#40 MT4

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Posted 20 July 2021 - 01:07 AM

The binocular Cancri is referring to is no longer shown on the APM page. It appears to have been discontinued. It is a much cheaper binocular than the non-ED MS, more like 300 EUR if I remember correctly.

 

Wow!  I would be seriously p**ssed.

 

So not only they don't do QA at the factory (going by the discussion on a different APM thread), they don't even check that they ship out the product being ordered.


Edited by MT4, 20 July 2021 - 01:08 AM.


#41 ihf

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Posted 20 July 2021 - 01:51 AM

Sigh. The MS ED is a fine bino if one gets a good copy. But I sense that Covid had some impact on operations.

 

The 20x80 should still be relatively easy to handle, including monopod and normal but tall photographic tripods (give it a try with your mounts). The 25x100 at twice the weight needs pretty serious photographic tripods. If you are able to handle the bulk and mounted weight it could be a good choice.



#42 Cancri

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Posted 20 July 2021 - 10:47 AM

To clarify. I made the order not at APM directly but another shop. It is a legit astro equipment shop and they have apologized. I assume the person doing the shipment confused something, due to essentially same naming. Only funny thing is, that they do not offer the cheaper model in their shop in the first place. Since I'm in the EU, shipping is quick, so not a big deal, but I was unhappy, of course.

Also as dufay mentioned, it is this model (not the shop I used): https://www.astrosho...ab_bar_1_select


Regarding the weight of the 25x100. That is indeed an argument. I can hold the 20x80 almost as easily as my smaller binocular. For its size it is still very light and easy to handle on a light tripod. Also easily portable if you go to a good place. 

However, I'm more concerned with the actual performance, the view the instrument will offer.




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