8-24 ish mm zoom

[LondonNeil]

It seems that the 3-8mm svbony is a star performer but what about at longer FL? What are the best zooms at each price point and what makes therm good? Are they worth buying or do the dissappint next to 2 or 3 fixed eps and a Barlow?  I was wondering this anyway but just had an old review article pop up on my phone, it love it 8-24mm celestron. Arī

[Don Pensack]

Some good ones:

Leica 8.9-17.8mm

APM 7.7-15.4mm Super Zoom

Baader hyperion Mk.IV 8-24mm

[John]

I've used the 3 that Don lists above. I still have a Baader Hyperion 8-24mm.

Their prices vary considerably as do their specifications - between £200 (Baader) and £750 (Leica). 

Their performance is more or less in line with their pricing. The Baader (IMHO) gets close to good fixed focal length eyepieces in performance but looses out in terms of FoV at the long focal length end. The APM performed pretty much as well as Pentax XW's I felt but, in my scopes, had to be used as a 2 inch eyepiece due to the inwards focuser travel needed in 1.25 inch mode. The Leica is really good optically, a touch better than most fixed focal length eyepieces and is often combined with the Baader VIP barlow to give shorter focal lengths.

I find the Baader useful to have in the eyepiece case and it's good for travel and outreach. The APM I had on loan and the Leica I tried for a few months but for some reason I didn't take to it in the long term  Others find it essential though. 

That's my short and sweet summary of those from my contact with them. Others may well have a lot more to say on them 🙂

 

Edited March 8 by John

[JeremyS]

I’m not much of a zoom guy, but I found the Leica to be a game changer. It’s very expensive, though. Perhaps not so much compared to a collection of EPs

[Zermelo]

Don has previously linked to this bench review of zooms by Ernest Maratovich.

The Svbony 7-21mm comes out particularly well. I have this, and the 9-27mm, and the (identical, OVL version of) the 7.2-21.5mm, and I find all three perform very well. The AFOV does vary a lot with magnification though, which is where the APM wins out.

Svbony also do a 8-24mm, but I've not seen any reviews of that one. The Baader mk IV is widely liked.

[Mr Spock]

I would say a slight shift in focal length and the Svbony 7-21 is one of the sharpest out there - if you can stand the narrow field of view.

[Cosmic Geoff]

2 hours ago, LondonNeil said:

8-24mm celestron.

I have a 8-24 mm BST Starguider zoom eyepiece, which was very inexpensive. It looks the same as the Celestron zoom, and in fact a number of the more budget 8-24 zoom eyepiece brands look (or looked) the same, as though they all came off the same production line.  

The Starguider zoom is OK optically, but the action is so stiff that I can't zoom it in situ, but have to take it out of the holder and grip it firmly in both hands to adjust the zoom. You get what you pay for, I guess.

[Ratlet]

11 hours ago, Mr Spock said:

I would say a slight shift in focal length and the Svbony 7-21 is one of the sharpest out there - if you can stand the narrow field of view.

That's what did me in for a lot of zooms.  The fov generally is quite tight and only gets tighter as you zoom.  One of the reasons I like the 3-8mm is it doesn't change.

I've got the 8-24mm zoom.  Good views but tight fov.  Quite a heavy eyepiece though.

[lunator]

I have the Baader Zoom, I use it quite a lot in the Dob. The field of view is a little tight at 24mm but I have never had an issue finding objects. From memory I think it give about 1° FOV in this scope/ eyepiece combination. 

I am an ortho eyepiece fan but the Zoom is very useful and as far as I am concerned I will be keeping it.

Cheers

Ian

[Naughty Neal]

As well as the SV215 3-8 zoom which many now own,  I bought the SV191 zoom 7.2 - 21.6 for a mere £23.99 on ebay some time before.

It now sells for around £75/ $100 and tbh it isn't too bad an ep for a cheapy and gives pretty good views, 42 - 65 degress fov    as one zooms to higher power the fov becomes greater.

I haven't given it much time as an ep but the views I have had with it I can't complain, I need to spend more time with it and then give some impressions of it.

I believe the SV191 is an improved and better ep then the SV135 7 -21 zoom.

Edited March 9 by Naughty Neal

[Don Pensack]

5 hours ago, Naughty Neal said:

As well as the SV215 3-8 zoom which many now own,  I bought the SV191 zoom 7.2 - 21.6 for a mere £23.99 on eBay some time before.

It now sells for around £75/ $100 and tbh it isn't too bad an ep for a cheapy and gives pretty good views, 42 - 65 degrees fov    as one zooms to higher power the fov becomes greater.

I haven't given it much time as an ep but the views I have had with it I can't complain, I need to spend more time with it and then give some impressions of it.

I believe the SV191 is an improved and better ep then the SV135 7 -21 zoom.

Measured apparent fields on the 7.2-21.6 zoom are 38° at 21mm and 59° at 7mm, so the fields aren't as wide as that, but that doesn't describe the quality of the image, just the width.

That is pretty narrow, though eye relief is good and there is no undercut on the lower barrel.

[F15Rules]

22 hours ago, Zermelo said:

Don has previously linked to this bench review of zooms by Ernest Maratovich.

The Svbony 7-21mm comes out particularly well. I have this, and the 9-27mm, and the (identical, OVL version of) the 7.2-21.5mm, and I find all three perform very well. The AFOV does vary a lot with magnification though, which is where the APM wins out.

Svbony also do a 8-24mm, but I've not seen any reviews of that one. The Baader mk IV is widely liked.

To be honest, I found the spreadsheet referenced  above totally confusing and user unfriendly, especially on my Smartphone.

What really bemused me were the claims that the Hyperion Zoom and Pentax XL 8-24mm zooms both had had "terrible image quality". That assertion is completely at odds with my experience with both these zoom eyepieces..

I have owned both of these and still have the Pentax Zoom. Both showed very good image quality: you might not like the narrower field at the lower power settings versus fixed length eyepieces, but the actual image quality (which by the way I judge by the pleasure I derive from what the eyepiece shows me, NOT this "spot" or that "aberration"), and the build quality of the units are excellent.

I can say with certainty that the Pentax zoom build quality is exemplary, and the images it delivers in terms of sharpness and contrast are very good indeed..very close to the fixed length XL and XW ranges.

Dave

[Second Time Around]

Ernest's bench tests are partly based on eyepieces supplied to him, mainly I believe by members of his forum.

If I remember correctly, he described the Mk III Baader zoom as "battered", which is why it may not have performed well.

The supposedly optically identical Mk IV came out much better, and I'm certainly pleased with mine.

The Baader is still not as good as my APM, that also has a wider (and constant) 66 degree field of view.  The APM is more expensive though.

Considerably more expensive still is the Leica.  I haven't tried this as it doesn't accept a Dioptrx astigmatism corrector.

Perhaps the best value for money is the Svbony 7-21mm zoom, that came out well in Ernest's bench tests.  No, it's not as good as the Baader, but it's a fraction of the price.  It's currently on sale direct from Svbony at just £32.76!

Edited March 9 by Second Time Around

[John]

38 minutes ago, F15Rules said:

To be honest, I found the spreadsheet referenced  above totally confusing and user unfriendly, especially on my Smartphone.

What really bemused me were the claims that the Hyperion Zoom and Pentax XL 8-24mm zooms both had had "terrible image quality". That assertion is completely at odds with my experience with both these zoom eyepieces..

I have owned both of these and still have the Pentax Zoom. Both showed very good image quality: you might not like the narrower field at the lower power settings versus fixed length eyepieces, but the actual image quality (which by the way I judge by the pleasure I derive from what the eyepiece shows me, NOT this "spot" or that "aberration"), and the build quality of the units are excellent.

I can say with certainty that the Pentax zoom build quality is exemplary, and the images it delivers in terms of sharpness and contrast are very good indeed..very close to the fixed length XL and XW ranges.

Dave

I'm glad that you have shared some experience with the Pentax Dave. Thats a zoom that I have not had the pleasure of trying out 🙂

 

[F15Rules]

Thanks John.

I first bought a Pentax zoom 8-24mm in 2016 from FLO. They had a sale on and the zoom was as I recall marked down to c£300 from £400..they aren't cheap zooms!

Circumstances led me to have to sell that one after only a few months, but I managed to find one about 9 months ago in great condition, with all original packaging etc.

It's especially good for short sessions where conditions may not be the best, but where the Pentax zoom, a baader zoom barlow and my Axiom LX 23mm UWA can be all I need to cover high magnifications to low power wide angle viewing.

Dave

Edited March 9 by F15Rules
Typo

[Zermelo]

1 hour ago, Second Time Around said:

It's currently on sale direct from Svbony at just £32.76!

I bought mine for less than that!

[Don Pensack]

16 hours ago, John said:

I'm glad that you have shared some experience with the Pentax Dave. That's a zoom that I have not had the pleasure of trying out 🙂

 

I tried the Pentax XF zoom and it was not sharp, had serious astigmatism at the edge, and was darker than fixed eyepieces of the same focal lengths.  That was at f/6.

So then I tried the Pentax XL and though it had slightly less astigmatism at the edge, and a trace wider field, it was even darker than the XF.

Comparing to Pentax XW eyepieces, the XL Zoom seemed to have a 25% neutral density filter added.

I do not recommend Pentax Zooms at all, though the XL might be OK as a Moon/planets observing eyepiece.

The Baader Hyperion Mk.IV was better in every way--wider, brighter, and sharper, and was the same price as the XL!

Edited March 10 by Don Pensack

[Spile]

Another vote for the Baader Hyperion IV. I combine mine with a 30mm ultra wide when I need a bigger field of view but it’s not an issue for me in reality.

[F15Rules]

17 hours ago, Don Pensack said:

I tried the Pentax XF zoom and it was not sharp, had serious astigmatism at the edge, and was darker than fixed eyepieces of the same focal lengths.  That was at f/6.

So then I tried the Pentax XL and though it had slightly less astigmatism at the edge, and a trace wider field, it was even darker than the XF.

Comparing to Pentax XW eyepieces, the XL Zoom seemed to have a 25% neutral density filter added.

I do not recommend Pentax Zooms at all, though the XL might be OK as a Moon/planets observing eyepiece.

The Baader Hyperion Mk.IV was better in every way--wider, brighter, and sharper, and was the same price as the XL!

I didn't remark on the XF zoom, only on the XW. I did use one (XF) for a short time and found it awful, literally, with huge amounts of false colour in night use. Others have sung its praises for solar observing, however (I dont do solar).

Regarding the XL zoom, which I have used quite extensively on and off over many night sessions, most recently in high end Takahashi and Vixen refractors at F8.1 and F7.7 respectively, I have never seen noticeable darkening of the XL zoom versus XWs : indeed, I actually let go an XW7mm and XL10.5mm simply because I felt I could see everything in the zoom that I could see in the fixed length eyepieces. A test of the quality of seeing I use very regularly is the visibility of the E & F stars in M42's Trapezium in Orion: I can see both on good seeing nights in the XL zoom at a magnificaion of c 100x..the same as with my fixed length eyepieces at the same magnification.

Here is the actual review I posted of the Pentax XL zoom I bought new from FLO in 2016..(my review follows the FLO product description and specifications).

 

Home  >  Eyepieces & Barlows  >  Pentax       Zoom Pentax XL 8-24mm Zoom £398 Model:  PentaxXLzoomPart Number:  70509 This premium quality six-element zoom eyepiece with ED and Lanthanum glass can be used in any telescope that accepts 1.25" accessories. Mechanically and optically this is a benchmark zoom eyepiece!  Zoom eyepieces enable the observer to match magnification to changing lighting or seeing conditions. This together with Pentax-grade optics results in an exceptionally useful eyepiece for terrestrial or astronomical observing.  For astronomical use, the zoom is usable for medium to high power observing with telescopes of all optical designs – from long focal ratio refractors down to fast f/4.5 Dobsonian reflectors.  Like most other Zoom eyepieces the FOV varies across the zoom range (from 38° at 24mm, to 60° at 8mm).  Features: Premium optical design with six lenses in four groups. ED (extra low dispersion) glass lens elements that include Lanthanum glass minimise chromatic aberrations and astigmatism. The result is very high contrast and centre resolution, with very little ghosting. All air-to-glass surfaces are fully multi-coated with proprietary Pentax SMC (Super Multi-Coated) anti-reflection coatings for high light transmission. For optimum contrast, lens edges and interior mechanical surfaces are all blackened to minimise reflections and ghosting. A rubber eyecup twists in and out of eyepiece body to optimise shield your eye from ambient light. The knurled rubber grip is turned to change magnifications. When the twist-up rubber eyecup is fully retracted for eyeglass use, the eye-relief ranges from 18mm (at 8mm setting) to 22mm (at 24mm). This enables observers with eyeglasses to see the entire field of view at low magnifications. When observing at high magnifications while wearing eyeglasses some vignetting of the outer field will occur (at these high magnifications you will likely be observing smaller objects that do not fill the FOV so minor edge vignetting is rarely a concern). The barrel of the eyepiece is marked in both magnifications (when used an 80mm Pentax spotting scope) and in focal lengths for astronomical observing. An index mark shows the power in use. The 1.25" nosepiece is threaded to accept 1.25" astronomy filters.  JIS-4 weatherproof construction for protection against wet weather and night-time dew. Weight: 550g (1.2lb) Length: 114mm (4.5") Width: 69mm (2.7") Customer reviews Write a Review:   Big Zoom, Big Performance, Big Price! 19 April 2016  |  David Having owned several Baader 8-24mm zooms, and having always hankered after a premium Pentax one, I finally took the plunge in early 2016. FLO service was excellent, as always and I received the eyepiece 24 hours after ordering it. First impressions, (with all too few later sessions due to weather and work commitments): Size: This is a Big zoom, considerably bigger than the Baader, but looks fantastic and comes with branded eyeglass cover and bomb proof bolt case for storage. Build quality - superb, exemplary: Zoom mechanism is quite stiff, due to the O Seal JIS waterproofing, but it does ease off and I have found that the best results come when using a Baader Click Lock 1.25" adapter in my 2" scope focuser. This holds the ep rock solid and enables plenty of torque to allow the smooth rotation of the zoom mechanism. A real, tangible step up on the build of the Baader zoom. Optics: The optics are very, very good for a zoom. In comparison to a world class Meade Japan UWA 14mm, I would say the Meade ever so slightly edged it in terms of faint stars visible, but it was a very slight advantage: from darker skies than mine this might disappear as a factor, and a tiny price to pay for having several eyepieces in one unit. Stellar images are pinpoint to the edge in my F7.7 apo doublet, with very good contrast. Field of view. The range of this zoom is 24mm, at which the specs say the view is 38degrees, going up to the highest 8mm power, at which the view is 60 degrees. On the face of it, the 24mm setting is quite narrow, but it never feels tunnel like, and the quality of the views are excellent. I have a wide 68 deg 24mm for that purpose anyway, so I do tend to look at this (and Baaders are the same fov) as an 8mm-20mm eyepiece. At 20mm the field is approximately 45degrees, and at 16mm about 50 degrees (same as most plossls). But, unlike many cheaper fixed eyepieces, the whole field of view is very sharp right to the edge. At 14mm and above, the field increases steadily up to the very healthy 60 degrees at 8mm. And, of course, you can increase or decrease the magnification in very small increments/decrements as conditions dictate. The zoom is NOT 100% parfocal. As you move from the 24mm setting to the highest 8mm setting, you need about a 2mm further in-focus setting on my focuser to achieve perfect focus. This is not a deal breaker at all for me, but just something to be aware of. Perhaps the best feature optically of the Pentax zoom is it's versatility. On any given night the seeing can vary quite significantly, and, when using fixed length eyepieces it can be very tiresome to have to keep swapping eyepieces to get the best view at a given moment. With the Pentax, you just dial in the magnification that gives the best view, simple, with just one eyepiece. So, you can observe for longer and see more. This is not a cheap eyepiece. But, it is of superb quality in all respects, and will last you a lifetime if you want it to. The Baader is an excellent unit to be sure, but in my honest opinion the Pentax has it comfortably beaten on all counts. And, at about twice the price of the Baader, so it should! Highly recommended.

 

Quote: The Baader Hyperion Mk.IV was better in every way--wider, brighter, and sharper, and was the same price as the XL!

The Uk price of the Pentax zoom when I bought it from FLO in April 2016 was £400. The Baader (I think it was the MkIII then) was around £150 - £170). 

Today (I've checked!), the Pentax zoom is £398 from FLO and the Baader MKIV is £237 from FLO.

These 2 fine eyepieces have never been the same price here in the UK. And that reflects the different class of build quality and labour/manufacturing costs of the Japanese Pentax and the Chinese made Baader. You might prefer the lighter weight and the cheaper price of the Baader, just as you might prefer, say, a Tele Vue Delos to a Celestron Xcel LX, but you'd have to acknowledge the difference in build quality.

I  myself am a fan of Baader equipment, and use a number of their products, including their Maxbright II binoviewers and have owned and liked their Morpheus range very much..but any fair minded person, having handled a Pentax XL zoom and a Baader zoom would, IMHO, have to say that the Pentax build quality is a significant step above the Baader..and that is reflected in the price! The Pentax will be intact and working perfectly in 30 or 40 years time or more..not sure that will be the case for the Baader zoom, which have been known for rattles, looseness, etc?

Dave

 

Edited March 11 by F15Rules
Additional text info

[Don Pensack]

I used the XL Zoom on nebulae and galaxies, and it rendered invisible many features I could see in the XW fixed focal lengths at the same focal lengths.

I didn't have the capability of measuring transmission, but I think the XL Zoom must have 15-20% or more less transmission than in the XWs.

I also used, a few years later, the same XL Zoom/XWs combination in a Pentax 80mm ED spotting scope, and the brightness difference at the same focal lengths was profound

in daylight use.  The XL Zoom was noticeably darker.  One of our testers commented that the XWs with sunglasses matched the XL Zoom without.  I saw that too.

[Louis D]

9 hours ago, F15Rules said:

Today (I've checked!), the Pentax zoom is £398 from FLO and the Baader MKIV is £237 from FLO.

I just checked US online retailers today, and the Pentax XL zoom goes for ~$329 at most retailers.  The Baader BHZIV goes for $309 at pretty much every retailer.  I recall the XL costing that much 20 years ago.

For comparison, the APM Super Zoom doesn't seem to have a US retailer since Don closed up shop.  However, direct from China via AliExpress under the Sky Rover brand it is available for as little as $329.  For the XL and BHZ, you'd more than likely need to add local sales tax.  The SZ would be tax/tariff free when ordered via AE.

[F15Rules]

3 hours ago, Don Pensack said:

I used the XL Zoom on nebulae and galaxies, and it rendered invisible many features I could see in the XW fixed focal lengths at the same focal lengths.

I didn't have the capability of measuring transmission, but I think the XL Zoom must have 15-20% or more less transmission than in the XWs.

I also used, a few years later, the same XL Zoom/XWs combination in a Pentax 80mm ED spotting scope, and the brightness difference at the same focal lengths was profound

in daylight use.  The XL Zoom was noticeably darker.  One of our testers commented that the XWs with sunglasses matched the XL Zoom without.  I saw that too.

Well, thank goodness that:

- I don't use small spotting scopes or big reflectors

- I dont wear sunglasses for astronomy observations, and

- the Japanese clearly sent their premier stock to the UK!

Your absolute right to draw your conclusions and give your opinions.

Same for me😉

Dave

[Louis D]

Well, I guess we'll just have to get someone to buy 10 XLs in each of the US and UK from various dealer stocks, and then run extensive tests on them to determine if the differences in viewing experiences are due to unit to unit variations.  😏

[LondonNeil]

How about the Stellalyra 8-24 lanthanum zoom? Specs seem good  a comfy 20mm eye relief and a reasonable 40⁰-60⁰ fov.  Any members here used it?

[LondonNeil]

Or the Helios hyperflex? same 40⁰-60⁰ fov and 18mm eye relief.  Are these 2 budget options flawed, decent for the money or.....an svbony 3-8 like little known gem?  Well.... probably not the later or the forum would be awash will l with praise for them,  but you know what I mean.