7.2mm - 21.5mm Zoom

[Johnny4365]

I know zooms seem to be somewhat frowned upon by some gazers but I thought one would be useful and good for the grandchildren to use.

Decided to go for a middle range one as I wanted a reasonable quality view to impress the kids but didn't want to panic every time they went near the eyepiece. (That was the Baader crossed off the list then!).

Read some good reviews for the skywatcher hyperflex 7.2-21.5mm zoom. Did a bit of research and found the following version of the what looks like the same eyepiece.

Skywatcher Hyperflex £129

Lunt £139.20

Omegon £112.70

Opticstar £99

Orbinar £76.49

Orion £179

TS Optics £134.90

They all look the same to me, just with different branding.

I realise that they may well be of different quality but I took a gamble on the cheapest one.

a

Got the Orbinar from Seben in Germany, it came in bubble wrap, without a case which was disappointing.

Not had much chance to use it yet (cloudy). I have manged a quick look at the Moon, Sun and Jupiter though.

I am no expert. and don't have much to compare it with,  but it seems ok. It is not parfocal as some refocusing is needed as you zoom in or out. Will update as I get to use it more.

 

[Mr Spock]

They do look the same don't they.

[Pig]

Johnny,

It will be interesting to know how it performs optically, what you think of the build quality and how you find the movement between the zoom settings.

[Johnny4365]

Good questions Pig.

Optically I need more time using it to comment really although focusing at high magnifications seemed a bit tricky, but that may be partly down to a scope focuser issue.

Build quality seems good, the eyepiece is quite large and reassuringly sturdy. (It survived the trip from Germany in some flimsy bubble wrap).

Eye relief is about 15mm I think and there is a screw up eye cup that works well.

The zoom action is smooth but slightly heavy so the eyepiece has to be fairly well secured in the focuser.

FOV is not great, especially when zoomed out, but thats zooms for you

[Johnny4365]

Another thing, I really must collimate my scope before commenting on any optical performance.

[N22]

Seben do one for £20 I think, looks identical to these. Has had OK reviews on here.

[alan potts]

Johnny,

Always check collimation before passing any comment on an eyepiece is sound advice, I do every time. I once got rid of a 40mm Aero because I didn't like the edges and then found a 41mm Panoptic was the same, I said some awful things about the Aero, like vey soft at the edges, which were totally unfounded. I was using an F10 scope at the time and now wish I had not been so quick off the mark to sell, as it weighs a fraction of the latter.

Look foward to the first light report.

Alan.

[Johnny4365]

The £20 Seben has a different zoom range 7.5-22.5mm and is not fully multi coated.

Great value for money eyepiece though and it comes with a case which mine didn't !

Seben 7.5mm - 22.5mm £20.59 from Amazon.

[bambuko]

Seben do one for £20 I think, looks identical to these. Has had OK reviews on here.

I think it would be fairer to say the reviews were "mixed"

BTW I was one of the people who bought it and no I haven't thrown it away yet ...

It may look identical, but it's what inside of it that matters and unfortunately you get (usually) what you pay for.

Johnny4365 - I hope your Orbinar version from Seben proves worthy the money!

[N22]

Hi bambuko,

I'm new to astronomy and thought this a good budget purchase, some people seem happy with it. If it turns out to be poor, it's not a great loss.

I am trying to decide which eyepieces to buy and will be looking at the generic ones that have good reviews.

Sometimes when paying a lot you don't get what you pay for either.

[bambuko]

The difficulty you have is that you have little other kit and experience (as a beginner) to compare it with.

If I had nothing else or just a basic stuff (as delivered) perhaps I would have thought it was OK?

The other extreme is of course relaying on reports from the guys who got money to burn   or are trying to extract the final 0.01% improvement.

Like yourself I am trying to do things on budget - it is not easy, but it is possible.

A lot will depend on what type and size of the scope you have as well.

I am too much of a beginner myself to offer advice   but there is many more people here who will be happy to help.

[N22]

Hi,

I agree, it's not easy trying to select eyepieces to get. I was avoiding the planetary ones, more interested in DSL, until I saw Jupiter for the first time last night.

I was getting more confused the more I read re. eyepieces.

Thought the seben might give me a better idea of what sizes to get.

My telescope is a WO 102 doublet, I bought it, don't laugh because I liked the look of it. I read reviews about it after which suggested it to be a generic item, but I am very happy with it, especially after last night's views of Jupiter.

I had been thinking of the BST ep, have you any experience of these. Any advise would be appreciated :-)

Sent from my LT30p using Tapatalk

[DRT]

I have a Seben 8mm - 24mm Zoom that I bought for £55. It is a solid piece of kit, comes in a good protective screw-top cylindar and does a good job with my SW 130p. The action is very smooth when zooming in and out with little or no need to refocus.

Worth considering.

[bambuko]

I have BST and like many here I am happy customer - good choice, good value (in my humble opinion).

I also heard good things (relatively speaking) about 8-24mm zoom piece that DRT mentions, but it is totally different animal (as far as I know) to a very budget 7.5-22.5mm version.

I'd guess it is also different to 7.2-21.5mm Orbinar one mentioned elsewhere in this thread.

Ideally we would have side by side comparison, but even than - eyepiece choice is very personal thing and what works for me might be no good for you.

[Schorhr]

The problem with the cheap Seben/Orbinar and it's reviews where a lot of people did not bother to read that it was about the 20gbp one, and then just posted "yeah, they are suppose to be decent" or "I have that! It's great!".

The cheapest of the Seben Zooms is actually quite bad if you ignore the price tag. It has a lot of reflections when there is something bright nearby, the view into the ep is a bit tube-ish, and as with most zooms the field of view gets narrow at the low magnification end.

It's ideal to replace missing eyepieces from a telescope found in a basement or something like that.

I also have the TS zoom, and while the 45gbp Seben is suppose to be a tad better though also covers a bit different focal lengths, I think I am able to say that the Zooms are okey but not the ultimate solution to your eyepiece needs. Especially a 24-32mm overview eyepiece is a must.

Else Seben/Orbinar also sells Plössl that are cheap and decent, especially if you buy them from their site instead of the "free shipping" ebay deals.

A 30mm Plössl (if you can make a DIY eyecup), a 10mm (9.5mm) Plössl and their 2x achromatic barlow make a decent and inexpensive combination for most typical entry level telescopes.

The 66deg eyepieces with the golden edge cost 18gbp as direct import and 27gbp from the UK. They are of decent quality and perform similar to Plössl but have a much nicer wide angle view.

I also have a 70 degree eyepieces Seben sells for 20gbp, they seem to be Erfle. The quality of the one I have seems good, threading better then their Plössl, black coating was good, reflections no issue.

The eye relief of the 12mm is already short, the 8mm will probably be not nice to use.

To wrap it up: The Zooms are OK, but two to three fixed focal length eyepieces won't be more expensive, but have a wider field of view especially on the longer focal lengths. Under f/6 they won't be sharp over the complete field though quite noticably.

[Reeny]

I have the £20 Seben Zoom - it is fitted with very poor plastic lenses.

The next model up should be fine from Seben.

The build quality of the case is quite good.

Mine has been to bits several times and re-assembled with no problems.

I just wish I hadn't wasted £20 on the plastic lenses

[DRT]

Prompted by this thread I had a go with the £55 Seben on Jupiter last night and tested it against my newly-acquired range of Celestron X-Cels. I now want to revise my position. It is a bit rubbish.

Jupiter was as clear as I have ever seen it through all of the X-Cels but I struggled to get a good clear image at any of the settings on the Seben. I also decided that t is easier to switch eyepiece than it is to fiddle with the zoom.

I still think it is a good option for someone on a budget as it could be a way of avoiding having to buy three or four EPs, but my advice would be to set it to the focal length you want, focus it and then enjoy the view. Trying to zoom in and out while viewing is simply frustrating.

[Johnny4365]

Great to get some opinions on these zooms, especially from people who can compare them to decent fixed focal length eyepieces.

I quite fancy the x-cels, but that will have to wait till another day (my birthday probably).

Anyone out there got one of the 7.2mm - 21.5mm zooms (any brand) out there that they would like to give an opinion on ?

[CSM]

I bought the Skywatcher 7 - 21mm zoom on the recommendation of someone who had sold and tried out quite a few, as have quite a number of other members of our society.  At £37 or thereabouts I would have thought it a much better buy for your grandchildren.  And it does work well.  The 15mm was as good or better than my Televue 15mm Plossl.

[John]

I've owned an 8-24mm Seben zoom which I bought to use for a public viewing session. It worked better than I expected at the 8mm - 15mm range but want downhill fast after that. The 7-21mm versions have a reputation for not being as good as the 8-24's.

Would I recommend one to someone ?. No, not really. I found standard Skywatcher plossls provided better views, with less light scatter, off axis glare and field edge distortion especially when you observe some more challenging objects.

For just giving someone a quick look through a scope the low cost zooms are fine for £20 or so though. 

[Gazetilludrop]

Has anyone tried the Panaview 32mm? If so what do you think to the performance?

[mylatestwhim]

Has anyone tried the Panaview 32mm? If so what do you think to the performance?

I have one and it's a lovely bit of kit. As it's brand new I'm hoping to give it a go tonight (fingers crossed) so i'll let you know. Quite a few people have them on here and they have a great rep.

They are mahoosive (hand grenade size) and they feel quality and expensive which i like a lot.

[John]

Panaviews are good for their cost but do show astigmatism in the outer part of the field of view scopes faster than around F/7. To be fair, that would be the same for any wide field eyepiece in that budget range. They are nicely finished eyepieces and are popular with many members of this forum.

[Johnny4365]

I was toying with the idea of getting a 2" eyepiece but my scope is an F5 so decided against it.

But then again whose to say I won't have a more suitable scope for them in the future.

I like the idea of high magnification but with a wide field of view.

[YKSE]

I was toying with the idea of getting a 2" eyepiece but my scope is an F5 so decided against it.

I'm not sure I'm following you.

The widest actual(true) field of view you can get in your scope with a 1.25" EP is with a 32mm 52 degree plössl, it is about 52*32/1000=1.66 degree, while if you get,

e.g. a 28mm 58 degree Max Vision, you'll get 28*68/1000=1.9 degree, framing the Plejade beautifully.

MV 28mm has much better edge correction than a Panaview, at essentially the same cost, and the exitpupil under 6mm will also enhance the darkness of background than a 32mm.