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Oberwerk 15x70 Deluxe

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#1 revans

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Posted 18 April 2024 - 08:53 PM

A couple of nights ago, while doing some imaging on one porch, I took my Oberwerk 15x70 Deluxe out onto a second porch facing east with views to the southeast.  Spica and Corvus were prominent in that part of the sky, but they were fairly low and impacted by my city lights which are brightest in that part of the sky. My main goal was to try and find the Sombrero galaxy. I found the small asterism immediately above it, but the Sombrero itself wasn't visible.

 

I did notice something about these binoculars that I had not previously.  This is a thin darker ring involving the extreme periphery of the FOV circumferentially and involving both barrels. 

 

I like to concentrate most on the center of the FOV and these binoculars give wonderful views in this area.  For some reason though, I found the peripheral darker rim distracting.  I've been using this pair of binoculars often for a few months and they are probably my favorite pair.  I've been debating whether or not to upgrade to the Oberwerk 15x70 Ultra, which I didn't go for initially because of the extra weight vs the Deluxe.  I'm thinking that maybe the darker rim was apparent to me because of the light pollution being more severe in this part of my sky.  Normally, with the sky background darker, I don't notice it. And I don't notice it in the daytime.

 

Am I the only one noticing the rim I describe using the Deluxe and does it make sense that by moving up to the Ultras I'd leave that dark rim behind me? I am otherwise very happy with the Deluxe model and have seen wonderful DSOs using it.  I especially like their modest weight and that I can use them for quite a long time in a zero gravity chair without getting tired.  But I'd like to not have this dark rim that is distracting me the past couple of observing sessions and am seriously considering upgrading to Oberwerk's Ultra version. I think it is an issue that occurs mainly when looking at areas of the sky that are brighter than Bortle 6.

 

Rick


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#2 Mark Y.

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Posted 18 April 2024 - 11:29 PM

Surprising thread by you, since I know how much you've always liked the 15x70Deluxe (I have one as well, btw).

 

Personally, I've never encountered your problem in my dark skies....Only an opinion here.....From all of the threads I've seen (you chiming in lots of times, btw) I'm willing to bet there's not a big difference between the Deluxe and Ultra. I believe Sir Fiske confirmed this, though he does like the Ultra more and also owns the APM MS 16x70ED.

For all I know...everything else similar, the lucky dog!lol.gif

 

I've gone back & forth myself on the 15x subject, since I use mine on a monopod (20x65ED and APM 34x80ED I have mounted on their own tripods, btw)....Since I've gone a bit wild with carefully improving my binocular collection in the past few months and am about to add one more, I have ruled out, for myself,  what I think is the ne plus ultra of this kind of instrument......Drum roll.....

 

I'd go for the APM MS 16x70ED hands down....I believe I read it didn't fit Fiske's facial comfort level but quite a few folks love this model....Me? Big Time!

 

That's where I'd spend my money and would bet there'd be a "meaningful enough difference" to make the move.

 

Great eye relief as well...........Good luck


Edited by Mark Y., 18 April 2024 - 11:30 PM.


#3 ABQJeff

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Posted 19 April 2024 - 02:41 AM

Hi Rick, I just took a look into my cloudy suburban skies (Bortle 6-7) with my 15x70 Deluxe, 12x60LW and Canon 15x50IS. I can see a very faint dark ring at the edge, but then also a very faint light ring just inside it, around the edge in both Oberwerk’s. But no different than you see at the edge of eyepieces in a telescope and not bothersome to me. Edge effects can be a result of your exit pupil, vignetting, off axis light being blocked/shadowed by the objective shade (what I think it is), etc.

I do not see any faint rings in the Canon, but that is 3.3 mm exit pupil and there are no objective lens shades (I have some on order).

#4 revans

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Posted 19 April 2024 - 07:27 AM

It is hard to describe the issue I had with the peripheral darkening, so I made a graphic that tries to show it in a different way that is less ambiguous than words but still not quite the reality... although it is closer I think.

 

test C
 
This is something like what I was seeing when looking at a pretty light polluted part of my sky.... Bortle 7 or maybe worse.... low down toward the horizon.  
 
I don't see this at the zenith which is more like Bortle 5-6.  Not everyone does, and some think it wrong (believing that the sky has only one Bortle level and not multiple for a given site) but I assign different Bortle levels to different parts of my sky.  I think people know what I mean by that and since I don't have a skymeter it is the best I can do.
 
Rick


#5 JoeFaz

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Posted 19 April 2024 - 07:45 AM

I haven't noticed this in my 15x70Ds, but to be fair I don't often look at the edge of the field. My only complaint with them has been less-than-stellar stray light control --- otherwise they're great.



#6 Cestus

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Posted 19 April 2024 - 11:15 AM

I haven't noticed it, but I haven't looked either. I have found the Sombrero galaxy, but it is difficult. For me the conditions had to be right and the neighbors had to have their lights off.



#7 harbinjer

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Posted 19 April 2024 - 11:28 AM

I would try 3 things if you're up for experimenting before plunking down the cash. First one is to get a hood or towel over your head to make sure it's not any kind of eyepiece side stray light or reflection. Bino bandit would be great too.

 

Next you can try extended dew shields. Make them out of whatever you have available, cardboard, rigid foam, kydex, or other plastic. See if that changes this. 

 

Third thing to try is a paper(or other temporary) aperture mask. See if 60mm or 50mm makes a difference. 

 

There is one other option: since this view is into light pollution, it is a very imperfect view anyway, and this just makes it a little less perfect. While it might be a bit distracting, it might be "acceptable" given the circumstances. And another bino that has less or none of this, maybe have other issues, such as being too heavy and making your arms tired too quickly or just not fitting your face as well. 

 

Lastly, I'd agree with Mark Y. that the APMs might be a better option if you're chasing more perfection. 



#8 sevenofnine

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Posted 19 April 2024 - 11:41 AM

Consider the Oberwerk 20x70EDU. You gain more power, ED glass and field flatteners which the 15x70U  doesn't have borg.gif


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#9 revans

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Posted 22 April 2024 - 08:10 AM

After some days of researching the issue with my Oberwerk 15x70 Deluxe binos, I've discovered that it is more noticeable if my pupils are widely dilated and more noticeable when looking through light polluted urban skies (Bortle 7, 8).  The issue is exacerbated by rotating the eyecup clicks to maximal outward extension and is ameliorated by inward rotation of the eyecups all the way back to the first click. 

 

I thought of a condition mentioned occasionally on this forum called "fuzzy field stop syndrome."  I don't know exactly what this means, but if it has something to do with slight blurring and darkening of the image at the extreme periphery of the FOV then maybe that is what my issue has been.

 

I've done some reading and carefully examined the exit pupil by looking through the objective end at arms length and viewing on and off the optical axis.  I can't find any problems doing this and assume the prisms are fine.

 

Rick


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