Svbony 8-3 zoom

[badhex]

2 hours ago, Ags said:

At one point millions of years ago, there were too many amateur astronomers on Venus.

Or dinosaurs! 

[Louis D]

While the image loaded, I thought you were going with this to explain the planet-wide smog of Venus:

[James9]

There seems to be a Christmas sale on from the manufacturers website:

https://www.svbony.com/svbony-sv215-1-25-3mm-8mm-planetary-zooms-eyepiece/

£106.78 + £21.09 for "Free Customs Clearance Shipping(8-15 business days)(Including customs clearance and taxes)". Total £127.86 delivered. 

$129.99 + tax et al to US buyers.

You can pay only £8ish for 25-35 day shipping but I presume you pay custom and taxes on arrival?

I think I will chance this for my fast Celestron Travel 70 at this price, unless anyone has heard otherwise? Hopefully it will be a nice useful little grab bag. 

[LDW1]

2 hours ago, James9 said:

There seems to be a Christmas sale on from the manufacturers website:

https://www.svbony.com/svbony-sv215-1-25-3mm-8mm-planetary-zooms-eyepiece/

£106.78 + £21.09 for "Free Customs Clearance Shipping(8-15 business days)(Including customs clearance and taxes)". Total £127.86 delivered. 

$129.99 + tax et al to US buyers.

You can pay only £8ish for 25-35 day shipping but I presume you pay custom and taxes on arrival?

I think I will chance this for my fast Celestron Travel 70 at this price, unless anyone has heard otherwise? Hopefully it will be a nice useful little grab bag. 

I don't think, due to the high powers obtained, that it will perform very well in a Travel 70 but I could be wrong !

[Moonlit Knight]

How well I remember the noise and heated debate from our cousins across the pond regarding the APM zoom. Virtually none of the predictions were correct and the waiting went on and on and before someone actually held one in their hands. 
 

I am not in the market for a zoom, but even if I was I would be waiting for lots and lots of positive reviews on here or CN

[LDW1]

26 minutes ago, Moonlit Knight said:

How well I remember the noise and heated debate from our cousins across the pond regarding the APM zoom. Virtually none of the predictions were correct and the waiting went on and on and before someone actually held one in their hands. 
 

I am not in the market for a zoom, but even if I was I would be waiting for lots and lots of positive reviews on here or CN

Almost all of the initial reviews / comments about that zoom are positive, on CN, even from the historical doubters ! How many do you mean by 'lots and lots of .....' ?

[Moonlit Knight]

FOV discussions in original post

[Louis D]

I figured for under $150 shipped, I'd give it a try.  Due to direct from China shipping, it may miss being a Christmas present.  However, my birthday is 3 weeks later, so it should definitely be here by then for a birthday present.

[Ratlet]

6 minutes ago, Louis D said:

I figured for under $150 shipped, I'd give it a try.  Due to direct from China shipping, it may miss being a Christmas present.  However, my birthday is 3 weeks later, so it should definitely be here by then for a birthday present.

Excellent a review we can trust!  Hopefully it's gets here sooner rather than later.  I'm in the market for a new planetary eyepeice and this could be a nice option.  Depends how it gets on at F5.

[At dusk]

I received my eyepiece almost two weeks ago, but due to the awful weather it's been impossible  to try this new zoom properly so far.

At least today I can post my first impressions. Although it was not the best night, there were wide patches of dark sky among the clouds. It was very cold and  I would rate the seeing as average. To top it off, high clouds caused a clear degradation of the views.

Anyway I used my grab'n'go set up: lunt 80 (lunt LS80 h Alpha without the solar module) on az-gti. To pump up magnification I always use a Takahashi 1,6 extender, because it works really well in all my refractors.

You must take everything with a pinch of salt, you can't make a review with only half an hour at the eyepiece, but it has really surprised me .The views through the zoom are absolutely amazing. Jupiter showed many details even with the less than ideals weather conditions. I compared the views with my toe 4 mm and the zoom in the same position. Definitely a bit more scatter although not really distracting, but the same level of detail. I suppose that with better seeing and less clouds it would be easier to find differences, but time will tell.

I think that it may offer 80-90% of the performance of 6 excellent toes for half the price of one.  I owned a TV 3-6 for several years, but I sold it because I prefer fixed eyepieces to zooms for planets and the TV is too expensive to keep both. However I'm sure I will keep this one.

 

[RT65CB-SWL]

I too have not had chance to try mine since it was delivered a few weeks ago, apart from the usual few terrestrial targets, ie trees, TV / FM aerials, rooftops, etc. Early impressions of it so far are looking good.

I cannot wait to see how it compares against my TV 3-6mm zoom when viewing the Moon or planets.

  

[Louis D]

After rescuing my Svbony package from the wrong community mailbox by catching our postman late this afternoon (holiday substitutes don't know the route), I have the Svbony 3mm-8mm in hand.  It's very nicely built with a smooth zooming action despite being about 6 °C straight from the mailbox.  I've never felt such a mechanically precise click-stop action.  It feels like a fine piece of machinery.  The upper part barely moves upward zooming to the 7mm and 6mm positions, then starts accelerating faster and faster toward 3mm position.  It increases a lot in length from 5mm to 4mm to 3mm.

Some quick measurements with a flashlight indicate it has about 8mm to 9mm of usable eye relief throughout the range with the eye cup folded down.  I can't even come close to seeing the entire field with eyeglasses when holding it up to my eye and viewing a lamp sans telescope.  Perhaps at the smallest exit pupils I'll be able to get away without eyeglasses despite having 2.5 diopters of astigmatism.

The eye cup folds down very easily without wanting to flip by itself like the original Morpheus eye cups.

The insertion barrel is about 36mm long.

I'll try it out in my normal testing rig when I get the chance.  For now, it feels way more expensive than it is.  I probably won't be able to get it out under the stars for a while given our extended forecast and Christmas.  After all, it has to go in my stocking for a few days. 😁

Edited December 21, 2022 by Louis D
Corrected insertion barrel length

[Louis D]

I got initial through-the-eyepiece images and measurements taken with the Svbony 3-8 zoom in my f/6 72ED field flattened refractor.  Here are my preliminary thoughts and findings:

• AFOV is pretty consistently 60 degrees, give or take a degree or so.  If you zoom fast enough and only pay attention to the illuminated circle, you can see it subtly changes.
• Usable eye relief is pretty consistently 8mm from the top of the folded down eye cup.
• Every clickstop focal length is within 0.1mm of the claimed focal length.  That is mind boggling given how far off I've found most zooms are from their marked focal lengths.
• The clickstops and zoom action shouldn't cause too much of an issue while viewing and zooming.  I didn't need to hold the eyepiece while zooming.  The 2" GSO diagonal's 1.25" eyepiece adapter's compression ring held it tightly without allowing rotational twisting.
• Focus is pretty much parfocal between any two clickstops.  I tweaked focus at each focal length to be certain of the best image possible, but it might not have been absolutely necessary.  I didn't try racking from one end to the other to check for end-to-end parfocality.  I also did not check for parfocality with other eyepieces known to focus at the shoulder.  I'll try to remember to do this the next time I have it out.
• You can't easily read the focal length scale if you have a GSO style 2" to 1.25" adapter that partially submerges the eyepiece's upper barrel to keep 1.25" eyepieces parfocal with 2" eyepieces if they all focus at the shoulder.  To be certain of which focal length I was at for each photo session, I racked the zoom collar back to 8mm and counted clicks downward from there.
• In the same holder, it's a bit difficult to grab the zoom collar and not the eye cup collar instead.  You have to get used to where it is, right at the top of the adapter.
• Zooming in while viewing to the 4mm and 3mm settings can be disconcerting as the top of the eyepiece lunges upward toward your eye.  I certainly was unprepared for this the first time I zoomed while viewing.
• There's no sign of SAEP (kidney beaning) or oddball edge artifacts at any focal length.  It made taking quality AFOV images a breeze.
• The fieldstop is nice and sharp throughout the focal range.
• It is a noticeably sharp eyepiece except maybe in the last 10% of the field near the edge at the shorter focal lengths.  Even then, it's relatively unobtrusive in daytime testing, and I wouldn't have noticed it without specifically looking for it in my photos.  I'll have to star test when the Holidays are over, and the sky clears, to confirm field sharpness at each setting.
• I started to come to the realization that this eyepiece might be a great eyepiece for newbies trying to populate their high power collection.  If eye relief isn't an issue, it can easily replace 3.2mm, 4mm, 4.5mm, 5mm, 6mm, 7mm, and 8mm TMB Planetary eyepieces along with 3.2mm, 5mm and 8mm Starguiders/Paradigms without giving up anything except eye relief.  That makes it a bargain at its current price.
• As I became more accustomed to it, I really began to appreciate what an optical engineering achievement this little eyepiece really is.  It took the 3-6mm Nagler Zoom as a starting point, lengthened the focal range upward to 8mm and widened the AFOV by 10 degrees, all while maintaining very good optical quality at an exceedingly affordable price point.  That, and the mechanical aspects are top notch as well.  It just exudes quality and attention to detail.

Bear with me through the Holidays.  It takes significant time to edit and composite the images for my test reports, time which is scarce right now.  I just wanted to give y'all a heads up that this eyepiece appears to be the real deal, and to snag it at the current discount if you want a good self-present for Christmas.

[LDW1]

Some time ago on a forum site, far far away when I pointed out the quality of Svbony products and their associated performances all round I was accused of working for them because all they were was a low life rebrander, it just wasn't possible.  Now I wish I was on their payroll, lol ! They just keep rolling them out, its good to see this is just the latest. I own a lot of their products including 3 zooms other than this one and nothing has let me down yet and as a side benefit I have saved a lot of cash.

Edited December 21, 2022 by LDW1

[Ratlet]

1 hour ago, LDW1 said:

Some time ago on a forum site, far far away when I pointed out the quality of Svbony products and their associated performances all round I was accused of working for them because all they were was a low life rebrander, it just wasn't possible.  Now I wish I was on their payroll, lol ! They just keep rolling them out, its good to see this is just the latest. I own a lot of their products including 3 zooms other than this one and nothing has let me down yet and as a side benefit I have saved a lot of cash.

The only valid complaint against svbony gear I've seen is that their advertising blurb is a tad optimistic.

Every other complaint tends to be "it's not as good as something that costs four times as much".

I'm just getting started and unless the kit is extremely poor quality, the weakest link in my setup is guaranteed to be me.  Having read @Louis D's reviews of other eyepieces I've enough to go on to know it's going to be a sensible purchase.  I consider him the gold standard for eyepiece reviews.

Edit:. Bought off their website instead.

Edited December 21, 2022 by Ratlet

[Ags]

I was going to get it this month... but I messed up a tax return. Hopefully February.

This doesn't just cover high powers. With my Long Perng 90, it would give everything from 167x to 0.9° FOV, so on the average evening no other eyepiece need apply.

[Louis D]

Now that Santa has officially gifted me this eyepiece at Christmas, I spent an hour+ with the 3-8 Svbony zoom in my 90mm f/6.7 APO last night viewing Jupiter, Luna, Mars, and the Pleiades.  Here are a few impressions that stuck with me:

• It is usable with eyeglasses at 8mm, a bit harder at 7mm, borderline at 6mm, and pretty much unusable from 5mm down to 3mm.  This runs contrary to my flashlight projection measurements showing a pretty consistent 8mm or eye relief.  At the long end, I'd say it has about 15mm of usable eye relief.  Zooming in, I can see the AFOV retreating into the distance (actually just narrowing in subtended angle) sort of like that "sunken place" scene in Get Out, forcing me to cram my eyeglasses harder and harder into the eyepiece.  For 5mm and below, I removed my glasses, but the eye relief was still almost too tight to use comfortably.  Based on that, I'd say ER drops from 15mm to 8mm as you zoom from 8mm to 3mm.  It doesn't feel like a linear change, though.  The ER shrinkage from 8mm to 7mm to 6mm seems as relatively small as the extension of the top of the eyepiece in that range.  As the top extends more going to 5mm, 4mm, and especially 3mm, the ER decreases more noticeably.
• It is close to parfocal, but for critical focus on objects like Jupiter's bands, an eighth turn of the fine focus knob was needed going from 8mm to 7mm.  Less was needed for the next few jumps.  End to end refocusing was definitely needed no matter which end was focused first.  However, on star fields like the Pleiades, the defocus was hardly noticeable.
• It seemed like there was a touch of field curvature (focus change) center to edge across the zoom range, but it was barely noticeable.
• There was a bit of light leakage through the field stop indicating it is not a physical ring defining it but rather the combination of several lens edges.
• Field distortion seemed low.  Yes, there was a bit of rolling ball effect going on during panning, but it was pretty minor.
• Star fields like the Pleaides looked great across the zoom range.  I'll have to try it on smaller star clusters on better nights to see if this observation holds up.
• There is some edge astigmatism starting around 5mm which gets progressively worse heading toward 3mm.  I think there is some from 8mm to 6mm as well, but it was vanishingly small.
• I was seeing yellow/purple fringing at higher powers across the field on Jupiter and Luna.  I don't think it was seeing or the scope, but since I didn't have time to pull out lots of eyepieces or other scopes for comparisons, I'll hold off making any more comments on my chromatic aberration impressions until I can verify them through comparative analysis.  It might just be an artifact of the FPL-53 triplet or the seeing.  I did remove the TSFLAT2 field flattener from the diagonal and my eyeglasses from my face, but the chromatic aberration remained.  Also, the center didn't seem to sharpen up all that much with the flattener removed.  It is known to impart a bit of spherical aberration there.
• On the whole It seems like an 8mm-4mm design stretched to 3mm.  Correction is excellent from 8mm down to 6mm across the field.  At 5mm, it is getting just a bit worse at the edges.  Things start to degrade a bit more rapidly going to 4mm, mostly at the edges but also some in the center.  Pushed to 3mm, and things seem to go south.  The central area is still passable, but the edges were not that great.  As such, it seems like a very good 5mm-8mm zoom as far as correction and eye relief goes.  The 4mm to 3mm range seems like it's mostly there for exceptional nights and strictly on-axis use.
• Ironically, the view of Jupiter was best at 8mm.  Zooming in didn't reveal any more band details last night.  Mars showed some albedo features, but I couldn't discern much else.  A washed out front was moving through causing a light breeze, so that may have contributed to less than perfect seeing conditions.
• The ~60° AFOV is very nice.  However the jump to even 70° with another eyepiece I had at hand did feel massively wider in comparison.
• Zooming action was smooth with just the right amount of dampening, and click stops were easy to move between.  I'd say they got the mechanical action just about right.
• The insertion barrel is so long that it noticeably protrudes below the 2" to 1.25" adapter of my GSO dielectric diagonal, but not long enough to strike the mirror.  This might prevent it from inserting all the way into some 1.25" diagonals.  I suppose I'll have to check it with my 1.25" WO diagonal that I mostly use for binoviewing. (Edit: I measured it to be about 2mm short of fully seating in the diagonal.)
• (Late addition I just remembered) I specifically looked for light scatter around bright objects, but I didn't see any obvious issues at any focal length.

This is certainly not a perfect eyepiece, but it would be absurd to expect it to be so given the relatively affordable price.  Overall, I'm happy with Santa's "gift".

Edited January 2, 2023 by Louis D

[Louis D]

I was out observing the moon last night with my 8" Dob without coma corrector (to eliminate its SA), the 3-8mm Svbony zoom, and the 5-8mm Speer-Waler varifocal.  Here are a couple of impressions from this session:

• The purple/yellow fringing was largely gone at 3mm and 4mm.  Only a small bit of yellow fringing remained in both eyepieces.  I must have been seeing violet chromatic issues introduced by the "APO" triplet at tiny exit pupils.
• Both were showing subtle mara contrast details quite well no matter where I put them in the eyepiece's AFOV.
• Both fields appeared flat of focus center to edge to my presbyopic eyes.
• 5mm seemed to be the limit of usable magnification last night.  Any higher, and my floaters got in the way, and no more fine detail was revealed in the Svbony.  Again, 8mm in both seemed best.
• The lack of a CC didn't seem to hurt axial details moved to the edge all that much with this extended object.  What was more important was slanting my view with or without eyeglasses by tilting my whole head and pulling back to get a straight on view of the edge rays.  This minimized chromatic aberrations.
• The S-W's 78° AFOV and 7-11mm of usable measured eye relief felt way more comfortable with and without glasses than the Svbony's 60° AFOV and 8mm of measured usable eye relief.  There's more to ER than what the measurements say with zooms/varifocals.
• I could still see the Svbony's AFOV receding away as I zoomed in.  The S-W didn't seem to do this all that much.  This made the Svbony's AFOV feel much narrower at higher powers than it really was.
• The Svbony's full field below 5mm is all but impossible to use for very long if you have long eyelashes like me.  I had to mash my eyelashes in the eye lens surround area to see the entire AFOV at 3mm and 4mm, and it was very uncomfortable.  I had to pull back on each eye blink to avoid getting gunk on the eye lens.
• With my 2.5 diopters of astigmatism, the views at 6mm to 8mm were subtly sharper with glasses than without despite the small exit pupils in the f/6 scope.
• The lack of parfocality of the S-W was far outweighed by the huge AFOV and slightly longer eye relief.  Much more of the moon, if not all of it at lower powers, would fit in the S-W's AFOV giving a much more satisfying view.
• The Dob didn't care how huge and long the S-W was compared to the Svbony as far as balance.  This might not be the case in a small alt-az mounted refractor, Mak, SCT, or Newt.
• Now I feel like I need to get the APM Super Zoom and pair it with a quality Barlow/Telecentric Magnifier to see if it would be the best high power zoom combination for my astigmatic eyes.

[Ratlet]

Soon™

[Louis D]

FYI, huge price drop on ebay for these.  $98+tax with free shipping from China on ebay US, and £102.00 shipped from China on ebay UK.

[Ratlet]

1 hour ago, Louis D said:

FYI, huge price drop on ebay for these.  $98+tax with free shipping from China on ebay US, and £102.00 shipped from China on ebay UK.

That's a good saving!  Wish I hadn't checked though.  The eBay seller has their new dual band filters listed!

[Ratlet]

That's it turned up now.  Feels very good quality.  The  1.25" barrel is quite a bit longer than my other eyepieces (about 15mm longer).  Shouldn't make a difference for me as I've got a reflector.  It'll be interesting to see how it compares next to the BST and barlow setup I've got at the moment.  Be able to make direct comparisons with the 8mm and 6mm and 4mm via the 12mm and 8mm using a barlow.  Best be quick though.  Jupiter is getting lower and lower.

[Don Pensack]

7 hours ago, Ratlet said:

That's it turned up now.  Feels very good quality.  The  1.25" barrel is quite a bit longer than my other eyepieces (about 15mm longer).  Shouldn't make a difference for me as I've got a reflector.  It'll be interesting to see how it compares next to the BST and barlow setup I've got at the moment.  Be able to make direct comparisons with the 8mm and 6mm and 4mm via the 12mm and 8mm using a barlow.  Best be quick though.  Jupiter is getting lower and lower.

Mars is still a decent size till about the end of the month.

[Ratlet]

15 minutes ago, Don Pensack said:

Mars is still a decent size till about the end of the month.

I'd love it if I could see anything on mars.  This far the limit of my observations has been "it's orange".  I've got a 130pds so short focal length for planetary, but it's been mostly maybe there is some differences in colour, some slightly darker bits, possibly.  If I can get better contrast on mars or see anything conclusively I'll consider the eyepiece a winner!

I'm quite excited to do some comparisons.  The Starguiders with the Starguider shorty X2 Barlow gives some wild reflections that look like firefly's darting about, especially the 8mm Also, from comparison with my 4mm Ramsden the contrast isn't great either as the cheapy Ramsden has given the most satisfying, contrasty views of Jupiter, although almost everything else was inferior.  On the nights that have supported the 4mm I actually prefer the views with the Ramsden on Jupiter just for the improved contrast.

[Don Pensack]

3 hours ago, Ratlet said:

I'd love it if I could see anything on mars.  This far the limit of my observations has been "it's orange".  I've got a 130pds so short focal length for planetary, but it's been mostly maybe there is some differences in colour, some slightly darker bits, possibly.  If I can get better contrast on mars or see anything conclusively I'll consider the eyepiece a winner!

I'm quite excited to do some comparisons.  The Starguiders with the Starguider shorty X2 Barlow gives some wild reflections that look like firefly's darting about, especially the 8mm Also, from comparison with my 4mm Ramsden the contrast isn't great either as the cheapy Ramsden has given the most satisfying, contrasty views of Jupiter, although almost everything else was inferior.  On the nights that have supported the 4mm I actually prefer the views with the Ramsden on Jupiter just for the improved contrast.

Look up a Baader Contrast Booster filter to see more details on Mars.

 

"Fireflies dancing about" is an apt description for reflections from the cornea to the eyepiece and back again.

Not all short focal length eyepieces are prone to this, but stay away from Kellners and Erfles as these are notorious for that.

Fully multi-coated Plössls are often good, but eye relief gets really tight about the 8mm range.

A suggestion I could make is to Barlow a longer focal length eyepiece you know doesn't have the problem.

It often is sharper across more of the field, too, because the Barlow doubles or triples the f/ratio of the scope before the light enters the eyepiece,

making the incoming rays more parallel, which reduces induced astigmatism in the eyepiece.

That really cleans up inexpensive designs like Plössls, Königs, and inexpensive widefields.