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Zoom EP's - the Value Proposition

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#1 Bob4BVM

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Posted 09 March 2021 - 02:59 AM

Cost is third on my list of why i like zoom EP's.

First is instant access to the perfect FL for the target, especially at moments of superb seeing, which are lost if you have to swap EP's.

 

Second is the sheer convenience of not having to fumble with EP swaps.

All three become even more important in a binoscope.

 

But doing a little cost analysis of various EP pairs for my binoscope has really brought the cost advantage to light, the difference becomes shocking when you need a pair of everything !

I'll let the numbers speak for themselves:

CS

Bob

EP Sets -options.png


Edited by Bob4BVM, 09 March 2021 - 03:01 AM.

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#2 astrokeith

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Posted 09 March 2021 - 03:30 AM

You are clearly a 'bino' person, and so cost and ease of swapping (two) eyepieces is important.

 

However.

 

You aren't comparing like with like. The zoom is a good compromise producing a range of focal lengths, but at a loss of FoV (48-68 deg) and eye relief (12-15mm for the Baader. Compared with the delos at 72 deg fov for the whole focal length range and 20mm eye relief. IMHO the optical performance of zooms is always a little less than an equivalent fixed eyepiece.

 

Just saying!


Edited by astrokeith, 09 March 2021 - 05:07 AM.

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#3 Jon Isaacs

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Posted 09 March 2021 - 05:27 AM

Zooms are definitely less expensive.  Whether or not they serve one's purpose effectively, do the job, that's a different question.

 

Consider the 10mm Ethos versus the Baader zoom.  The 10mm Ethos has the same true field of view as the fully zoomed out Baader zoom.  For star hopping in a larger scope, the Ethos can be much more effective because you are getting the same TFoV at 2.4 x the magnification, no need to zoom out and in.. Those faint galaxies pop in the 10mm Ethos. 

 

As far as cost analysis, where are the affordable eyepieces, the Plossls, the Astro-Tech Paradigms?  I'd say they are more comparable in terms of image quality and AFoV.  

 

And with the zooms, where are the low power eyepieces to make up for the narrow field of view at the longer focal lengths?  

 

For me, I will always have the fixed focal length wide field eyepieces, they are sharper off-axis, probably sharper on axis and offer a substantially wider field of view.  The question for me is whether having a zoom as a niche eyepiece is useful.  At this point, having owned the Baader Mk 4 for 2-3 years, it seems like the answer is no.  I have it but don't use it. 

 

Jon


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#4 Avgvstvs

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Posted 09 March 2021 - 05:27 AM

I agree with Keith that field of view is important

The main reason I don't use them even though I have tried a few over the years

It all depends what is important to you


Edited by Avgvstvs, 09 March 2021 - 05:29 AM.

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#5 clearwaterdave

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Posted 09 March 2021 - 06:26 AM

I think zooms are a great tool.,And many believe you are replacing only 5 or 7 fixed focal length eyepieces.,but in use they replace "every focal length" in their spread., 8mm- 8.3mm- 8.6mm and so on.,

  It seems like many need a wider fov and a perfect edge to edge view to be happy.,I don't have scopes that demand high priced well corrected eyepieces ,.and I don't need a huge fov to enjoy the view.,

 So again it is just a matter of opinions,,.but zooms really cover more FL's than they are ever given credit for.,thus adding greatly to their value,.imho.,


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#6 Jon Isaacs

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Posted 09 March 2021 - 06:51 AM

I think zooms are a great tool.,And many believe you are replacing only 5 or 7 fixed focal length eyepieces.,but in use they replace "every focal length" in their spread., 8mm- 8.3mm- 8.6mm and so on.,

  It seems like many need a wider fov and a perfect edge to edge view to be happy.,I don't have scopes that demand high priced well corrected eyepieces ,.and I don't need a huge fov to enjoy the view.,

 So again it is just a matter of opinions,,.but zooms really cover more FL's than they are ever given credit for.,thus adding greatly to their value,.imho.,

 

They may cover finer steps than they are given credit for but they don't over more focal lengths.  In some sense they cover a smaller range than they claim, the focal lengths longer than 16-18 mm are often of not much use.  

 

It's not so much about enjoying the view though, honestly, a 24mm with a 44 degree AFoV is not my cup of tea.  Rather it is the narrower field.  At the 8 mm focal length in my largest scope, the TFoV is less than 0.20 degrees,   At 24mm, it's 0.37 degrees.  I get twice that with the 21mm Ethos.  

 

Jon



#7 clearwaterdave

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Posted 09 March 2021 - 07:20 AM

They may cover finer steps than they are given credit for but they don't over more focal lengths.  In some sense they cover a smaller range than they claim, the focal lengths longer than 16-18 mm are often of not much use.  

 

It's not so much about enjoying the view though, honestly, a 24mm with a 44 degree AFoV is not my cup of tea.  Rather it is the narrower field.  At the 8 mm focal length in my largest scope, the TFoV is less than 0.20 degrees,   At 24mm, it's 0.37 degrees.  I get twice that with the 21mm Ethos.  

 

Jon

Jon.,For $853.00 for that one eyepiece it should give you twice the fov.,and polish your shoes.,That is comparing apples to elephants if I've ever heard it.,lol.,


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#8 Jon Isaacs

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Posted 09 March 2021 - 07:26 AM

Jon.,For $853.00 for that one eyepiece it should give you twice the fov.,and polish your shoes.,That is comparing apples to elephants if I've ever heard it.,lol.,

 

It comparing eyepieces.  Sure it costs more but I have it, I had it before I bought the zoom, I use it, I don't use the zoom.  In this value proposition, there is value in performance.  

 

Jon


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#9 Jon Isaacs

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Posted 09 March 2021 - 07:44 AM

Jon.,For $853.00 for that one eyepiece it should give you twice the fov.,and polish your shoes.,That is comparing apples to elephants if I've ever heard it.,lol.,

 

Dave:

 

A second take:

 

An apples to apples comparison:  The Baader zoom at 24mm to the $60 Astro-tech 25mm Paradigm.  The Paradigm offers a significantly wider field of view, I calculate about 42% wider and is more useful star hopping and just observing. 

 

In Bob's analysis, I think it's important to consider limited field of view of the zoom at the longer focal lengths and at least include an eyepiece along with the zoom that comes close to maximizing the TFoV of his binocular telescope.  Those low power wide field views in one of the attractions of a binocular telescope.  A pair of 24mm Panoptics or something similar seem quite popular with binocular telescope owners. 

 

Jon 


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#10 clearwaterdave

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Posted 09 March 2021 - 07:47 AM

As I said above.,it seems like many need a wider fov and a perfect edge to edge fov to be happy.,And you make it clear that this need comes at a huge price.,One that many can only dream of.,You are very fortunate.,You know what you want and you can afford to have it..Not everyone does or can.,



#11 Jon Isaacs

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Posted 09 March 2021 - 08:48 AM

As I said above.,it seems like many need a wider fov and a perfect edge to edge fov to be happy.,And you make it clear that this need comes at a huge price.,One that many can only dream of.,You are very fortunate.,You know what you want and you can afford to have it..Not everyone does or ca

I can be happy with anything.  But.. a wider field of view has many virtues.  And it doesn't have to be expensive. That is one reason why I included the 25mm Paradigm.  It's very affordable, $60.  I have one.  I use it a lot. It's not the sharpest in a fast scope but I am OK with that. 

Beyond that, I have a variety of 2 inch eyepieces. Some quite expensive.  But I also have a 34mm 72 degree Svbony that cost me $65 shipped, brand new. Again, it's not the sharpest off-axis but it does provide a field of view nearly as wide as the 31mm Nagler and far wider than the Baader zoom, about 2.2x wider.  And I use it a fair amount.. 

 

Sharp to edge with a wide field of view is what costs, wide with sharp in the center, not so sharp off axis, that's affordable. 

 

In my 10 inch F/5 Dob, the Baader zoom offers a maximum field of view of 0.83 degrees, the Svbony, 1.83 degrees.  It's effective star hopping and does a pretty good job on the Pleiades. 

 

Jon


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#12 Sarkikos

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Posted 09 March 2021 - 09:05 AM

You are clearly a 'bino' person, and so cost and ease of swapping (two) eyepieces is important.

 

However.

 

You aren't comparing like with like. The zoom is a good compromise producing a range of focal lengths, but at a loss of FoV (48-68 deg) and eye relief (12-15mm for the Baader. Compared with the delos at 72 deg fov for the whole focal length range and 20mm eye relief. IMHO the optical performance of zooms is always a little less than an equivalent fixed eyepiece.

 

Just saying!

Have you tried the Leica ASPH Zoom?  I did not see a lessening of optical performance when I compared the Leica Zoom with XW's or Delos.  The only caveat would be more obvious EOFB in the Leica Zoom under some conditions.  I only saw a difference in performance when comparing the Leica Zoom to XO's, with the XO's giving a bit sharper image of planets during good seeing.  The LZ also had a somewhat warm tone compared to the neutral-cool tone of the XO's.

 

But for me the obvious improvement in the Leica Zoom vs the Baader Zooms, was the parfocality of the Leica.  I can no longer use the Baader Zooms in any of my telescopes without having to refocus from high to low power, or vice versa.  I don't need to do that for the Leica.  For me, this is more important than a narrowing of the AFOV at low power.

 

Mike


Edited by Sarkikos, 09 March 2021 - 09:10 AM.

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#13 j.gardavsky

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Posted 09 March 2021 - 01:01 PM

If you can swallow the "initial cost of investment" into the Leica Asph. Zoom, then it is finally cheaper than a set of the Delos, when comparing a similar range of the focus lengths.

 

And with the Baader VIP Barlow (designed by Dr. Pudenz, Zeiss) you can dip shorter into the typical focus lengths of the Abbe orthos.

 

No wonder,

that America is the biggiest market for the Leica Asph. Zoom to be mounted on the astronomy telescopes.

Leica Cameras eventually manufacture many more units of their zoom, than their APO Televid 82mm spotting scopes.

 

Best,

JG


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#14 Sarkikos

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Posted 09 March 2021 - 01:14 PM

So Leica makes more Zooms than the spotting scope the Zoom was meant to go on?  :grin:

 

Mike


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#15 Jeff Morgan

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Posted 09 March 2021 - 01:23 PM

You aren't comparing like with like. The zoom is a good compromise producing a range of focal lengths, but at a loss of FoV (48-68 deg) and eye relief (12-15mm for the Baader. Compared with the delos at 72 deg fov for the whole focal length range and 20mm eye relief. IMHO the optical performance of zooms is always a little less than an equivalent fixed eyepiece.

 

Like with like?

 

That would not be Baader vs. Delos. I would also probably not replace a bunch of Delos with a Baader.

 

But Leica vs. the Delos (or some combination of high-end Tele Vue or Pentax) is another kettle of fish entirely.

 

Everyone posting here has been here a long time. And anyone who has been here a long time is not going to be using a beginners eyepiece like a Plossl or Paradigm. They are going to have a case full of DeLites (or better). So why would you not look at a top-flight zoom?

 

I ran the Leica vs. Premium test over three months. Daytime. Night time. Every time I could. I really struggled to see any differences optically.

 

https://www.cloudyni...nian/?p=5743994

 

I approached it very cautiously, but the results always came up the same and were undeniable. The Leica was every bit as good optically. And more versatile. And more productive in use (greatly reduced eyepiece and filter swapping).

 

After selling off all of those Tele Vue and Pentax (spring of 2014), I can confirm Bob's financial analysis. One of the few times in this hobby I actually came out ahead on the money lol.gif


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#16 Jeff Morgan

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Posted 09 March 2021 - 01:24 PM

No wonder,

that America is the biggiest market for the Leica Asph. Zoom to be mounted on the astronomy telescopes.

Leica Cameras eventually manufacture many more units of their zoom, than their APO Televid 82mm spotting scopes.

 

I just wished they made a version in a 2" barrel so I could lose the adapter ... lol.gif


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#17 j.gardavsky

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Posted 09 March 2021 - 01:30 PM

So Leica makes more Zooms than the spotting scope the Zoom was meant to go on?  grin.gif

 

Mike

Yes, this is the case, but I still don't have the numbers, and Leica Cameras company won't tell.

 

One part of manufacturing of the Leica Asph. Zooms has been contracted with the Leica plant in Portugal, and these zooms have the inscription "Portugal" instead of "Germany".

 

I have purchased the zoom together with the Leica APO Televid 82mm, both of them Made in Germany.

 

A similar situation has been with the Zeiss Diascope (spotting scope), but here with their fix focus eyepieces.

 

And lots of the discontinued old Leica spotting BWW fix focus eyepieces has found their last destination in the astronomy telescopes. And similarly with the Swarovski fix focus spotting eyepieces - the old Habicht series, and the new SW.

 

https://www.cloudyni...der-vip-barlow/

https://www.cloudyni...evid-eyepieces/

https://www.cloudyni...ting-eyepieces/

https://www.cloudyni...cope-eyepieces/

 

Best,

JG


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#18 j.gardavsky

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Posted 09 March 2021 - 01:35 PM

I just wished they made a version in a 2" barrel so I could lose the adapter ... lol.gif

In Wetzlar at the HQ,

they have never heard about the 2" Imperial standard for the astronomy telescope eyepieces,

 

JG



#19 Jeff Morgan

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Posted 09 March 2021 - 01:42 PM

In Wetzlar at the HQ,

they have never heard about the 2" Imperial standard for the astronomy telescope eyepieces,

 

JG

 

Maybe we should ask them for 50.8mm - smooth barrels of course.


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#20 rexowner

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Posted 09 March 2021 - 01:53 PM

Happy to see that the OP also uses spreadsheets to make EP decisions.

 

I have a Mark IV 8-24 BHZ.  It's a quality product, but I just can't warm up to it.

The spreadsheet I used analyzing it vs single focal length EPs is below.

I'm holding on to the BHZ for outreach, but not really a zoom person.

 

The value of magnification is understood for e.g. Solar System binoviewing targets,

but one thing that stood out to me in analyzing the BHZ was that **TFOV "zooms"

less than 2x.**

 

I tried a second BHZ for binoviewing, but my nose hits the top of the EPs and it's

physically uncomfortable.  I use DeLites + 24mm Panoptic for binoviewing.  I

don't really mind swapping, and they're lighter than the BPZ, and give a wider

range of superior views.  Like the OP, cost was a tertiary consideration for me.

 

For EZ monoviewing, to me the Pentax XWs give a wider range of better views IMO.

Three of them covers the BHZ range within a few %, and there's options to go higher or lower.

 

YMMV.

Attached Thumbnails

  • Screen Shot 2021-03-09 at 10.44.08 AM.jpg

Edited by rexowner, 09 March 2021 - 02:35 PM.


#21 rexowner

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Posted 09 March 2021 - 02:06 PM

Ignore this 2nd post.  Oops.


Edited by rexowner, 09 March 2021 - 02:09 PM.


#22 JamesDuffey

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Posted 09 March 2021 - 02:06 PM

I agree with Jon, the shortcomings of the narrow FOV at the long focal lengths dilutes the zoom value proposition substantially, particularly when zooms are recommended to new scope owners who are trying to expand their eyepiece selection. Usually the new scope owner will have a 25mm Plössl. The 24mm end of the often recommended 8-24mm zooms is a step down from the view that one has through the 25mm Plössl rendering the upper range of the zoom inferior to what the newbie has. Even the 21mm setting of the less recommended 7-21mm zoom does not offer a substantially better view than the 25mm Plössl. 

 

What of other focal lengths? For a beginner, magnifications in the ratio of 1:2:3 are often recommended and offer a wide selection of magnifications at reasonable steps. One can meet those requirements at roughly the same cost as the inexpensive zooms with a 2x Barlow and an 8mm Paradigm/Starguider.  If you want to compare to the increased quality of the oft recommended BHZ, one can buy 8mm, 12mm, 25mm Paradigms/Starguiders and a 33mm Plössl for the cost of the BHZ. 

 

I realize that there is advantage for a bino-viewer not having to juggle 4 eyepieces, but that is not usually a concern for a beginner. And while it is neat to zoom in on a double star to split it, there aren’t many beginners that start out splitting double stars. 



#23 rexowner

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Posted 09 March 2021 - 02:13 PM

 

> What of other focal lengths? For a beginner, magnifications in the ratio of 1:2:3 are often recommended and offer a wide selection of magnifications at reasonable steps. 

IMO, if I had it to do over again, (and didn't have the 24mm Plossl), I'd get the 20mm, 10mm and 7mm Pentax XWs,

and they would be EPs I'd likely have forever.


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#24 SeattleScott

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Posted 09 March 2021 - 02:16 PM

How about a $300 BHZ compared to 25, 18, 15, 12 and 8 Paradigms? Same cost essentially, covering the same range of focal lengths basically, and the Paradigms have a significantly larger average AFOV. Now I haven’t used Paradigm to compare the views with BHZ, but the BHZ isn’t exactly a world beater in contrast and edge correction. It might be generally a bit better than Paradigm, which would help compensate for the AFOV advantage of the Paradigm. Idk. Now one could argue the BHZ is more convenient, or can dial in magnification a little more precisely, so that adds some value. But just looking at cost savings, the BHZ isn’t any more affordable than a set of 5 paradigm.

The BHZ has a 3x magnification range and less than 2x TFOV range. Which makes it pretty good for varying magnifications and not so hot at varying FOV. Consequently, like most zooms, it is handy for small targets that don’t need wide AFOV for framing and struggles with extended objects.

It gets different with the much more expensive Leica Zoom as it offers premium optical performance and wide AFOV. I could see a Leica replacing a few Delos or XW. But then it costs about three times as much. And I remember hearing the Leica isn’t the best with sub-F5 reflectors, so those with big, fast Dobs might stick with Delos and similar. Haven’t ever used the Leica. I could be wrong.

Scott
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#25 Sarkikos

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Posted 09 March 2021 - 02:24 PM

I agree with Jon, the shortcomings of the narrow FOV at the long focal lengths dilutes the zoom value proposition substantially, particularly when zooms are recommended to new scope owners who are trying to expand their eyepiece selection. Usually the new scope owner will have a 25mm Plössl. The 24mm end of the often recommended 8-24mm zooms is a step down from the view that one has through the 25mm Plössl rendering the upper range of the zoom inferior to what the newbie has. Even the 21mm setting of the less recommended 7-21mm zoom does not offer a substantially better view than the 25mm Plössl. 

 

What of other focal lengths? For a beginner, magnifications in the ratio of 1:2:3 are often recommended and offer a wide selection of magnifications at reasonable steps. One can meet those requirements at roughly the same cost as the inexpensive zooms with a 2x Barlow and an 8mm Paradigm/Starguider.  If you want to compare to the increased quality of the oft recommended BHZ, one can buy 8mm, 12mm, 25mm Paradigms/Starguiders and a 33mm Plössl for the cost of the BHZ. 

 

I realize that there is advantage for a bino-viewer not having to juggle 4 eyepieces, but that is not usually a concern for a beginner. And while it is neat to zoom in on a double star to split it, there aren’t many beginners that start out splitting double stars. 

Some beginners eventually learn that AFOV is something but not everything.

 

Mike


Edited by Sarkikos, 10 March 2021 - 07:55 AM.

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