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Svbony 3-8mm Zoom In The Pipeline...

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#51 Sarkikos

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Posted 03 September 2022 - 09:11 PM

1.5-4mm zoom..

Thanks.  I will correct it.  My verbal thinking runs faster than my mathematical thinking. grin.gif

 

Actually, I had a typo with "3-5mm" zoom, corrected that, and forget to correct the math part of it. 

 

You folks need to give me a chance to edit my posts.  I edit in real time.

 

Mike


Edited by Sarkikos, 03 September 2022 - 09:13 PM.

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#52 Voyager 3

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Posted 03 September 2022 - 09:13 PM

Thanks.  I will correct it.  My verbal thinking runs faster than my mathematical thinking. grin.gif

 

Mike

Nah, I saw you write 3-5mm zoom at first before editing so your math skills does work fine.. 


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#53 Sarkikos

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Posted 03 September 2022 - 09:14 PM

Nah, I saw you write 3-5mm zoom at first before editing so your math skills does work fine.. 

Yeah, looks like the short-term memory needs improvement.  :grin:

 

Mike


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#54 Star-Hunter

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Posted 10 September 2022 - 02:20 PM

Hi all! I was able to compare the Svbony 3-8mm and the nagler 3-6mm at Jupiter with a good quality optics newton 150mm f\5. The image is very similar, including the correction of aberrations. I noticed Jupiter reflections on the nagler only at the 4mm focus. It also seemed to me that the background with Nagler is a little darker, and the image itself is a little less yellow than after Svbony 3-8mm. Eye relief is comparable. Of course, the large focus range of the Svbony 3-8mm is impressive and very useful. The mechanics are also very similar - the nagler's "trunk" also dangles a little. The eye lens in 3-8 is slightly larger. I had great "pleasure" walking with these eyepieces on the Moon.


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#55 RLK1

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Posted 10 September 2022 - 02:49 PM

Hi all! I was able to compare the Svbony 3-8mm and the nagler 3-6mm at Jupiter with a good quality optics newton 150mm f\5. The image is very similar, including the correction of aberrations. I noticed Jupiter reflections on the nagler only at the 4mm focus. It also seemed to me that the background with Nagler is a little darker, and the image itself is a little less yellow than after Svbony 3-8mm. Eye relief is comparable. Of course, the large focus range of the Svbony 3-8mm is impressive and very useful. The mechanics are also very similar - the nagler's "trunk" also dangles a little. The eye lens in 3-8 is slightly larger. I had great "pleasure" walking with these eyepieces on the Moon.

Thanks for the update. It seems from your description that the Svbony is a bit warmer in tone than the Nagler. I prefer neutral or cool tones on planetary eyepieces but I like the focal range in the Svbony zoom and eye relief isn't an issue for me since I don't wear glasses.  Now, if they'll just get the eyepiece off the drawing board and onto their website for sale...


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#56 Ernest_SPB

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Posted 19 September 2022 - 02:01 AM

Yesterday I have looked the eyepiece. Detailed review will be ready later.

 

Here are just first impressions:

  • The measured focal lengths are close to the declared ones: 7.8 mm instead of 8 mm at the long end.
  • The eyepiece is parfocal to itself: the parfocal parameter is -4.5 mm over the entire zoom range.
  • AFOV is almost constant over the entire range - 60 degrees, with a slight cutoff to 58 at the long end.
  • Eye relief is modest: 11 mm at the long end with reduction to 7 mm at the short end. The field is strongly cut in glasses.
  • Pretty annoying glare, with or without glasses - from 1 to 3 rather bright "flies". And in general - an increased level of light scattering (bright halos around the stars).
  • Quite noticeable positive (pincushion) distortion of straight lines. Anamorphosis at the edge is a sign of positive angular distortion (except for 8 mm nominal).
  • There are artifacts associated with poor light protection are noted at the edge of the field of view (absence or ineffective lens blackening?)
  • Aberrations on the axis are compensated close to ideal - pure diffraction.
  • There are strong appearance of field aberrations at the FOV edge. At focal lengths of 8 and 6 mm - astigmatism + curvature bring the size of the spot (image of a star) in the F4 telescope to 20-25 arc. minutes and in the F5 telescope up to 10-12 arc. minutes. At focal lengths of 3 and 4 mm, coma and astigmatism (sagitta) make aberration spot within a size of 30-37 arc. minutes in F4 and 22-28 minutes in F5.
  • In the FOV zone, the dimensions of the aberration spots are approximately half as large and mostly represented by astigmatism.

I think it is a strong competitor to 3-6 Nagler zoom. Wider zoom range and AFOV, a bit longer eye relief. It would be nice if manufacturer improves AR coating and light protection. 


Edited by Ernest_SPB, 19 September 2022 - 02:14 AM.

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#57 MortonH

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Posted 19 September 2022 - 02:23 AM

Hmmm, "pretty annoying glare" is a deal breaker in my book.  I hope they address the coating and light protection.


Edited by MortonH, 19 September 2022 - 02:25 AM.

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#58 Sarkikos

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Posted 19 September 2022 - 10:09 AM

  • The eyepiece is parfocal to itself: the parfocal parameter is -4.5 mm over the entire zoom range.

Do you mean you need to adjust the focus by 4.5mm from one end of the zoom range to the other end?  Then it is not parfocal.

 

Mike


Edited by Sarkikos, 19 September 2022 - 10:09 AM.


#59 Ernest_SPB

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Posted 19 September 2022 - 11:22 AM

Front focus position 4.5 mm from ref. point (connect body and barrel) to eye lens side is not changed zooming.

See F parameter here https://www.televue....page.asp?id=214


Edited by Ernest_SPB, 19 September 2022 - 11:25 AM.

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#60 george tatsis

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Posted 19 September 2022 - 02:04 PM

It takes a top of the line eyepiece to marginally beat the TV Nagler zoom .The ZAOs, Pentax XO and TMBs SMs are the ones

 

that stand out and may edge out the NZ when the seeing allows them to do so. According to what we have been reading here

 

on CN for years now, the owners who possess both the NZ and the premium ones detect a slight  improvement on the best of

 

nights in favor of the premium eyepieces. Nothing earthshaking in my book though. Apart from the glass quality, the coatings

 

and the baffling of the Nagler zoom are excellent. If Svbony does not eliminate the coating issues along with the light protection

 

/ baffling obstacles, there in no competition IMHO.

 

George


Edited by george tatsis, 19 September 2022 - 11:00 PM.

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#61 Agnes

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Posted 19 September 2022 - 02:55 PM

I will try to wait for reviews of production models before puchasing, but I think this eyepiece would work well for me, particulary in small f6-ish refractors. Glare issues do not sound promising, but maybe not such a problem with doubles which would be my main target.


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#62 jonbosley

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Posted 19 September 2022 - 04:16 PM

Can anyone confirm it is indeed a click stop zoom? This could make an excellent bino viewer option for planetary/lunar observation. 
 



#63 Ernest_SPB

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Posted 20 September 2022 - 01:09 AM

Yes, it is... Click stop zoom. What I tested has stops on 3-4-6-8 mm, but it seems SvBONY in production extends the set to 3-4-5-6-7-8 mm 


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#64 therealdmt

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Posted 20 September 2022 - 05:00 AM

It takes a top of the line eyepiece to marginally beat the TV Nagler zoom .The ZAOs, Pentax XO and TMBs SMs are the ones

 

that stand out and may edge out the NZ when the seeing allows them to do so. According to what we have been reading here

 

on CN for years now, the owners who possess both the NZ and the premium ones detect a slight  improvement on the best of

 

nights in favor of the premium eyepieces. Nothing earthshaking in my book though. Apart from the glass quality, the coatings

 

and the baffling of the Nagler zoom are excellent. If Svbony does not eliminate the coating issues along with the light protection

 

/ baffling obstacles, there in no competition IMHO.

 

George

For me, its not that it needs to beat the TV, but merely that it provides good views along its zoom range while being considerably less expensive than the TV.

 

I agree that baffling and coating are important. If the quality is too low, I don’t need it. Meanwhile, if the price is too high, I won’t get it. I’d just like a good, mid-priced short focal length zoom. If that’s not possible, I can do without 


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#65 Sarkikos

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Posted 20 September 2022 - 07:05 AM

For me, its not that it needs to beat the TV, but merely that it provides good views along its zoom range while being considerably less expensive than the TV.

 

I agree that baffling and coating are important. If the quality is too low, I don’t need it. Meanwhile, if the price is too high, I won’t get it. I’d just like a good, mid-priced short focal length zoom. If that’s not possible, I can do without 

If the new Svbony 3-8 Zoom were optically as good as the TV 3-6 Zoom, and the same price or even a bit more than the TV 3-6 Zoom, I would buy the Svbony.  For me, the price would not be too high.  But we know from prior experience that's not how Svbony works.

 

Mike


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#66 emilslomi

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Posted 20 September 2022 - 02:14 PM

Interesting zoom. I have the 3-6 TVZ. It is a good eyepiece. I use it regularly, and I enjoy the views. And I do not have fixed focal length eyepieces below 6mm. BUT ... at 6mm the views through a 6mm Fuji ortho are clearer and those of the Burgess Ultramono much clearer and sharper. Of course, they have less and much less FOV and eye relief, which, luckily, I can live with.

 

With my scopes and skies, 8mm is good on ordinary nights, while 6mm may be a bit much. A zoom picking up at 8mm would be nice. I would try it.

 

Emil


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#67 Starman1

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Posted 20 September 2022 - 03:39 PM

Yes, it is... Click stop zoom. What I tested has stops on 3-4-6-8 mm, but it seems SvBONY in production extends the set to 3-4-5-6-7-8 mm 

Ernest,

Have you posted the results of your test?


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#68 Starman1

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Posted 21 September 2022 - 09:39 AM

Encouraging the throw of the eyepiece riser tube is longer than the TV, means less severe optical curves.

The throw is longer because:

--the range is longer, 3-8mm instead of 3-6mm.  It is mostly this.

--the lenses are larger and the apparent field is larger. This results in the lenses having to move farther for the same effect.

It does not mean the curves are any shallower.


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#69 MrFreeze

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Posted 27 October 2022 - 07:49 AM

SVbony are now advertising that this is now available. (On their website - not the "app" they have just changed their mind and are now saying it is pre-order -  shipping on Nov 30) https://www.aliexpre...4883846890.html Has anyone ordered one yet, and if so what do they think of it? It looks peculiar with the extendy thingy - I don't know what that is about.

 

David


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#70 Sarkikos

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Posted 27 October 2022 - 08:15 AM

SVbony are now advertising that this is now available. (On their website - not the "app" they have just changed their mind and are now saying it is pre-order -  shipping on Nov 30) https://www.aliexpre...4883846890.html Has anyone ordered one yet, and if so what do they think of it? It looks peculiar with the extendy thingy - I don't know what that is about.

 

David

The extendy thingy is a copy of how the 3-6mm and 2-4mm Tele Vue Nagler Zoom eyepieces focus.  

 

https://www.televue....?id=49&Tab=_rev

 

Mike


Edited by Sarkikos, 27 October 2022 - 08:16 AM.


#71 Sarkikos

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Posted 27 October 2022 - 08:19 AM

Specifications:

1.Brand: SVBONY
4.Barrel Size: 1.25"
5.Apparent Fie
2.Model: SV215
3.Focal Length 3-8mmld of View: 56°
6.Coatings: Fully Multi-Coated
7.Blackened Lens Edges: Yes
8.Eye Relief: 10mm
9.Parfocal: Yes
10.Filter Threads: M28.5x0.6
11.Lens Elements: 6
12.Lens Groups: 4
13.Barrel Type: With safety undercut
14.Rubber Eye Guard: Yes

 

https://www.aliexpre...randl_shipto=US

 

Parfocal? fingertap.gif  Seeing would be believing. 

 

Alleged improvements over the 3-6 TV Zoom:

 

* 3-8mm focal length range

* 56 degree AFOV 

 

Only $149.  (Maybe I should list that in the improvements?)

 

Mike


Edited by Sarkikos, 27 October 2022 - 08:22 AM.

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#72 Sarkikos

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Posted 27 October 2022 - 08:24 AM

For me, its not that it needs to beat the TV, but merely that it provides good views along its zoom range while being considerably less expensive than the TV.

 

I agree that baffling and coating are important. If the quality is too low, I don’t need it. Meanwhile, if the price is too high, I won’t get it. I’d just like a good, mid-priced short focal length zoom. If that’s not possible, I can do without 

And, for me, it better be parfocal.  Why does anyone put up with a zoom eyepiece that has to be refocused as you change the focal length?  ohmy.gif  Otherwise, I'd only be using it in slow telescopes that could optically overcome the nonparfocality.  A Barlow could also do that, but I don't see putting a Barlow on a 3-8mm eyepiece.

 

Mike


Edited by Sarkikos, 27 October 2022 - 08:26 AM.

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#73 RLK1

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Posted 27 October 2022 - 01:31 PM

And, for me, it better be parfocal.  Why does anyone put up with a zoom eyepiece that has to be refocused as you change the focal length?  ohmy.gif  Otherwise, I'd only be using it in slow telescopes that could optically overcome the nonparfocality.  A Barlow could also do that, but I don't see putting a Barlow on a 3-8mm eyepiece.

 

Mike

Their advertising does say some minor refocusing may be necessary. 


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#74 akdwivedi

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Posted 28 October 2022 - 02:53 AM

From aliexpress -- quote ---

1.The apparent field of view and the usable eye relief to stay the same as the focal length changes.
2.Smooth zoom action with click-stops at 3, 4, 5, 6,7 and 8mm for quick changes to precise preset magnifications
3.Parfocal across the entire zoom range (minor tweaking may be necessary, however)
4.6-Element/4-Groups, Fully Multi-Coated optics for remarkable sharpness, contrast and color correction
5.Fold-down rubber eyeguard and a rubber grip ring.
6.With safety undercut for a secure fit in the eyepiece holder
7.The zoom eyepiece is designed to provide the best balance of contrast, comfortable eye relief, and resolution for the critical planetary observer, particularly those with ultra-premium short focal length refractors.

--- unquote----

 

Which scopes will qualify under ultra-premium short focal length refractors - doublets/triplet refractors in 200-400mm focal length.. Ultra-Premium does puts a very tough constraint.. looks not good for my planetary SCT scopes.. though it might work on my FPL53 doublet.



#75 emilslomi

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Posted 28 October 2022 - 02:41 PM

At about f6, the eyeiece will give what many consider the max magnification for that aperture. Now, many visual scopes are above f6. Using the full range of the eyepiece will only pay off if the optics are good enough to take more than the usual 50x per inch. That MAY be what they mean.

 

Is the eyepiece available noe?

 

Emil


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