Zoom eyepiece comparisons.

[Guest]

Just now, bosun21 said:

I was going on the quality of the optics not on how many were sold. I should have been clearer with my post.

Hahahahahaha.  How much is a Lecia? 

[bosun21]

3 minutes ago, Mike Q said:

Hahahahahaha.  How much is a Lecia? 

I’m too scared to look at the current price 😂

[Guest]

1 minute ago, bosun21 said:

I’m too scared to look at the current price 😂

Yeah its like buying a Schmidt and Bender rifle scope.... If you have to ask....you cant afford it. 

[bosun21]

1 minute ago, Mike Q said:

Yeah its like buying a Schmidt and Bender rifle scope.... If you have to ask....you cant afford it. 

I could afford one but at around £800 I question whether the slight improvement of the optics justifies the price. I am considering the APM zoom though. I also want a Televue 2.5x Powermate. Want, want, want, that’s the problem.

[Guest]

15 minutes ago, bosun21 said:

I could afford one but at around £800 I question whether the slight improvement of the optics justifies the price. I am considering the APM zoom though. I also want a Televue 2.5x Powermate. Want, want, want, that’s the problem.

There is what i want and what i am willing to spend..... 800 bucks on a eyepiece.... Not a chance.  The wife would kill me

[cajen2]

12 minutes ago, Mike Q said:

There is what i want and what i am willing to spend..... 800 bucks on a eyepiece.... Not a chance.  The wife would kill me

With her rifle, using a Schmidt and Bender, I suppose....😉

[Guest]

Just now, cajen2 said:

With her rifle, using a Schmidt and Bender, I suppose....😉

I dont spend that kind of money on the scopes I buy for mine lol

[cajen2]

1 minute ago, Mike Q said:

I dont spend that kind of money on the scopes I buy for mine lol

Of course not....when you need a 16" dob! 😄

[Guest]

1 minute ago, cajen2 said:

Of course not....when you need a 16" dob! 😄

I dont need.... I have lol

[Louis D]

3 hours ago, LDW1 said:

Absolutely no doubt but at what price for a zoom eyepiece ? Especially on an average nite sky !

3 hours ago, LDW1 said:

We started out with reasonable priced zooms and now the rarer, much, much higher priced ones are showing up as is usual, lol.

Look at the OP's equipment list.  I have a feeling a rather ordinary zoom like the BHZ would not be well received and would be resold or returned.  By way of comparison, the Leica in particular is supposed to rival Pentax XWs in sharpness and contrast.  It just suffers a bit at the edges in sub-f/5 scopes compared to the XWs.

[LDW1]

7 minutes ago, Louis D said:

Look at the OP's equipment list.  I have a feeling a rather ordinary zoom like the BHZ would not be well received and would be resold or returned.  By way of comparison, the Leica in particular is supposed to rival Pentax XWs in sharpness and contrast.  It just suffers a bit at the edges in sub-f/5 scopes compared to the XWs.

In the 2nd paragraph of their OP they mention Svbony zoom eps so I proceeded to give my experience with easily obtainable zoom eps, nothing more, nothing less. Whether anyone reads is not an issue, a concern. If you have more in hand experience than I that is good, the more knowledge the better. The Sv's do perform extremely well for their cost, just ask my Mark IV that I sold, lol !

Edited March 13, 2023 by LDW1

[Louis D]

1 hour ago, LDW1 said:

In the 2nd paragraph of their OP they mention Svbony zoom eps so I proceeded to give my experience with easily obtainable zoom eps, nothing more, nothing less. Whether anyone reads is not an issue, a concern. If you have more in hand experience than I that is good, the more knowledge the better. The Sv's do perform extremely well for their cost, just ask my Mark IV that I sold, lol !

You are correct, and the OP does have the BHZ and prefers it to the Celestron Regal zoom (of which I have several and have never noticed any kidney-beaning).  I haven't read of anyone touting any of the Svbony zooms replacing their BHZ except for the 3-8mm replacing their BHZ+2.25x Barlow combination.  Aside from outreach usage, I doubt the OP would be particularly happy with the Svbony zooms.  I suppose the Svbony zooms are cheap enough that the OP could buy a few and try them out.

[Stu]

11 hours ago, LDW1 said:

We started out with reasonable priced zooms and now the rarer, much, much higher priced ones are showing up as is usual, lol.

I was simply answering your point that all zooms have a narrow afov when actually there ARE wider afov zooms out there.

Consider that a good zoom can replace a number of more expensive eyepieces like XWs or Delos then they become a potentially more cost effective option. The APM actually looks good value though the zoom range is a little more restricted, the main benefit is that the afov effectively remains constant through the range.

[LDW1]

8 hours ago, Louis D said:

You are correct, and the OP does have the BHZ and prefers it to the Celestron Regal zoom (of which I have several and have never noticed any kidney-beaning).  I haven't read of anyone touting any of the Svbony zooms replacing their BHZ except for the 3-8mm replacing their BHZ+2.25x Barlow combination.  Aside from outreach usage, I doubt the OP would be particularly happy with the Svbony zooms.  I suppose the Svbony zooms are cheap enough that the OP could buy a few and try them out.

Reread my post, this is from lengthy experience but just remember we are talking zooms, try and understand their intent.

[LDW1]

4 hours ago, Stu said:

I was simply answering your point that all zooms have a narrow afov when actually there ARE wider afov zooms out there.

Consider that a good zoom can replace a number of more expensive eyepieces like XWs or Delos then they become a potentially more cost effective option. The APM actually looks good value though the zoom range is a little more restricted, the main benefit is that the afov effectively remains constant through the range.

I think many are missing the virtuous point of using zooms ! When I want wide fields of view I turn to my widefield eyepieces, at a cost !

Edited March 13, 2023 by LDW1

[LDW1]

Carry on my fellow astronomers, me I'm going to grab one of my 3 Svbony zooms and head out to do some Ha work. Clear Skies to you all !

[Stu]

24 minutes ago, LDW1 said:

I think many are missing the virtuous point of using zooms ! When I want wide fields of view I turn to my widefield eyepieces, at a cost !

To repeat, you made an inaccurate statement that all zooms were narrow afov, that is what I corrected. If you want a zoom with a reasonable afov, comparable with the likes of Delos or XW then they are available and highly useful too.

[LDW1]

3 minutes ago, Stu said:

To repeat, you made an inaccurate statement that all zooms were narrow afov, that is what I corrected. If you want a zoom with a reasonable afov, comparable with the likes of Delos or XW then they are available and highly useful too.

I am waiting for one to come out like my 76° eps upwards to 100°, now thats widefield. When I find / get one it will be my only one but until then. Only incorrect based on interpretation !

[Second Time Around]

Here are some updated thoughts on the zooms I've used so far, including the new APM Superzoom:

Hyperflex 9-27mm.

I compared it with my Baader during the day on my shed. Even though the focal lengths are lower, the actual field of view at 27mm is about the same as the Baader 8-24mm at 24mm. Nor was it as sharp as the Baader in my f/6 refractor. I was planning to try it with my Quark, but there were no sunny days or clear nights before I passed it on to two of my grandkids to use with the 70mm f/10 I bought them for Xmas. Not surprisingly, it was better at f/10. Not Dioptrx compatible.

Svbony 7-21mm.

I tested it on a very low down Saturn, and surprisingly found that on my f/6 refractor it was as good as the Baader on axis. Sharpness fell off somewhat off axis though, plus the field of view was quite a bit smaller. However, trying it on prominences at f/26 with my Quark it was way, way behind the Baader, seemingly because of lower contrast. I bought this for outreach rather than risking my expensive zooms and have kept it for this. It's very small and light, even compared to other Svbony models, so would be useful in binoviewers.  Dioptrx compatible with O-ring.

Celestron 8-24mm.

The version I bought was the spotting scope one, so it might be different to the astro model, but I believe that optically they're identical. The first thing I noticed was that it was even less parfocal than my Baader. In fact, no zooms I've tried are parfocal to my aged eyes, but might be to someone younger. The field of view was also smaller than the Baader. What disqualified it completely though was that it wasn't threaded for filters or screw in Barlows, although I think the astro version is. I therefore returned it without further testing. Dioptrx compatible with O-ring.

Baader 8-24mm.

This is more expensive than those above, and not surprisingly outclassed all of them, both in sharpness/contrast and field of view.  Until I bought an even better but more expensive APM Superzoom it used to be by far my most used eyepiece, although I also own a selection of quality fixed focal length ones. Can be used as a 1.25 or 2 inch eyepiece.  Dioptrx compatible with O-ring. The only downside, that's really important only for binoviewing with a Dioptrx, is that unlike most zooms the eyelens rotates when zooming.

APM 7.7-15.4mm.

The best zoom I've ever used, although not cheap.  As sharp as the Baader but with somewhat better contrast.  Wide 66 degree field of view throughout the entire zoom range.  Indeed, the APM has a wider actual FOV at 15.4 mm than the Baader does at 24mm!  Can be used as a 1.25 or 2 inch eyepiece, but needs extra infocus with 1.25 inch.  Dioptrx compatible with inexpensive M43 to T-thread adapter.

Edited March 16, 2023 by Second Time Around

[LDW1]

9 minutes ago, Stu said:

To repeat, you made an inaccurate statement that all zooms were narrow afov, that is what I corrected. If you want a zoom with a reasonable afov, comparable with the likes of Delos or XW then they are available and highly useful too.

You are correct but the number of zooms that fall into that bracket vs the number of zooms  available gets pretty small and costly and for what. To replace all ones single eps ?

[LDW1]

2 minutes ago, Second Time Around said:

Here are updated some thoughts on the zooms I've used so far:

Hyperflex 9-27mm.

I compared it with my Baader during the day on my shed. Even though the focal lengths are lower, the actual field of view at 27mm is about the same as the Baader 8-24mm at 24mm. Nor was it as sharp as the Baader in my f/6 refractor. I was planning to try it with my Quark, but there were no sunny days or clear nights before I passed it on to two of my grandkids to use with the 70mm f/10 I bought them for Xmas. Not surprisingly, it was better at f/10. Not Dioptrx compatible.

Svbony 7-21mm.

I tested it on a very low down Saturn, and surprisingly found that on my f/6 refractor it was as good as the Baader on axis. Sharpness fell off somewhat off axis though, plus the field of view was quite a bit smaller. However, trying it on prominences at f/26 with my Quark it was way, way behind the Baader, seemingly because of lower contrast. I bought this for outreach rather than risking my expensive zooms and have kept it for this. It's very small and light, even compared to other Svbony models, so would be useful in binoviewers.  Dioptrx compatible with O-ring.

Celestron 8-24mm.

The version I bought was the spotting scope one, so it might be different to the astro model. The first thing I noticed was that it was even less parfocal than my Baader. In fact, no zooms are parfocal to my aged eyes, but might be to someone younger. The field of view was also smaller. What disqualified it completely though was that it wasn't threaded for filters or screw in Barlows. I therefore returned it without further testing. Dioptrx compatible with O-ring.

Baader 8-24mm.

This is more expensive than those above, and not surprisingly outclassed all of them, both in sharpness/contrast and field of view.  Until I bought an even better but more expensive APM Superzoom it used to be by far my most used eyepiece, although I also own a selection of quality fixed focal length eyepieces. Can be used as a 1.25 or 2 inch eyepiece.  Dioptrx compatible with O-ring. The only downside, that's really important only for binoviewing with a Dioptrx, is that unlike most zooms the eyelens rotates when zooming.

APM 7.7-15.4mm.

The best zoom I've ever used, although not cheap.  As sharp as the Baader but with somewhat better contrast.  Wide 66 degree field of view throughout the zoom range.  Indeed, the APM has a wider actual FOV at 15.4 mm than the Baader does at 24mm!  Can be used as a 1.25 or 2 inch eyepiece, but needs extra infocus with 1.25 inch.  Dioptrx compatible with inexpensive M43 to T-thread adapter.

Yes about the APM and even moreso the new Svbony equivalent but many, many, many observers want more range for their $ than what they offer. Thats why I personally didn't buy either, we aren't all moon / planetary focussed ! As for the others, we all have our experiences.

[Louis D]

20 minutes ago, LDW1 said:

I am waiting for one to come out like my 76° eps upwards to 100°, now thats widefield. When I find / get one it will be my only one but until then. Only incorrect based on interpretation !

Unless you demand parfocality, my 5-8mm Speers-Waler Zoom has a constant, measured, 78 degree AFOV through its range.  Of course, I consider it a varifocal rather than a zoom, but it was sold as a zoom.  They also made an 8-12mm version.

There was also a device that could be inserted between the Smyth lens group and positive lens group for early Nagler type ultrawide field eyepieces to convert them into ultrawide angle zooms.  I can't find references online to it anymore, but I think it was called "Zoom-Set" or something similar.

[Stu]

25 minutes ago, LDW1 said:

You are correct but the number of zooms that fall into that bracket vs the number of zooms  available gets pretty small and costly and for what. To replace all ones single eps ?

Yes, exactly that. Some people have chosen to replace fixed eyepieces with high end zooms.

[Second Time Around]

On 13/03/2023 at 12:45, LDW1 said:

Yes about the APM and even moreso the new Svbony equivalent but many, many, many observers want more range for their $ than what they offer. Thats why I personally didn't buy either, we aren't all moon / planetary focussed ! As for the others, we all have our experiences.

Whilst I take your point about the zoom range, the shorter the range the easier it is to make a high quality zoom at a given price point.

Also, the smaller field of view at the low power end of zooms has to be taken into account.  For instance, with my Baader zoom I used it almost entirely at 8-16mm, then skipped over the other focal lengths to 24mm just to get the widest field of view. 

With the 7.7-15.4mm APM I have almost the same focal lengths as the Baader but a much wider apparent field of view at low powers.  As I posted above, the true FOV of the APM at 15.4mm is wider than that of the Baader at 24mm.  Plus the magnification is higher meaning a darker sky background and so almost always more stars visible.

There's a market for zooms at various price points of course.  I'm lucky that I can now at last afford the APM, but appreciate that many members will be in the same boat as I was not so long ago when my budget was tight.  On the other hand, the quality and wide field of the APM zoom means I need less fixed focal length eyepieces now as Stu posted.

 

Edited March 15, 2023 by Second Time Around

[LDW1]

4 minutes ago, Louis D said:

Unless you demand parfocality, my 5-8mm Speers-Waler Zoom has a constant, measured, 78 degree AFOV through its range.  Of course, I consider it a varifocal rather than a zoom, but it was sold as a zoom.  They also made an 8-12mm version.

There was also a device that could be inserted between the Smyth lens group and positive lens group for early Nagler type ultrawide field eyepieces to convert them into ultrawide angle zooms.  I can't find references online to it anymore, but I think it was called "Zoom-Set" or something similar.

Sounds good, can you find me one !  Maybe a few others on here would maybe like one as well ? Can you let me know ?Maybe talk to Mr. Speers directly.