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PF 65 ED eyepieces? (1 Viewer)

gcole

Well-known member
A lot of folks comment on the Pentax XW eyepieces being very good when paired with the Pentax scopes. But if you read some more recent reviews of astro eyepieces the Televue DeLite equals it, and in some situations has improved resolution. While the Televue DeLos has been rated by a number of reviewers as having better optics across the board than the XWs. Both Televues have easier eye placement and are more comfortable to use. (and yes, I have compared the 14mm XW and the Televues listed myself, and I also found the Televues to have easier eye placement and to be more comfortable).

This is one of several reasons we went with the Telvue DeLite and DeLos eyepieces in our Pentax scopes.

The Pentax XW series provides some drizzle, fog, splash protection that the Televues lack, but there is no reason you can't have both eyepiece lines in your kit for different conditions.

What I do find interesting is the current need to have a zoom eyepiece on all scopes. Viewers will accept a substandard zoom eyepiece over a high quality fixed eyepiece. Sure costly zooms have greatly improved, but they also may sacrifice other traits one might need (eye relief), or like (a large sweet spot).

The spotting scope industry has reached a point where there are very few brands that offer fixed eyepieces, and those that do offer a very limited variety. Most setups have zoom eyepieces. If that one zoom eyepiece that Brand A sells doesn't work for you for some reason, then Brand A is out of the running as a scope option. Or if Brand B's zoom does work for you, but is 4x what you can afford, then what other options are out there?

I am also surprised at the number of people who buy a scope that takes astronomy eyepieces, then spend as little on an eyepice as possible and comment that it's a bad scope. The eyepiece is a very critical component on a scope and should not be cheaped out on.

This is why I like the Pentax PF line, and the approach of the Celestron Regal M2 line. The buyer can find an eyepiece that meets their need without being locked into one option.

From past experience with Televue higher end telescope eyepieces , I have no reason to doubt your assessment of the Televue DeLite and DeLos giving outstanding views similar to the Pentax XW’s when used on the Pentax Spotting Scopes. Apparently many purchasers who purchase scopes that would take Astronomy 1.25” style eyepieces either by design or modification, opt to buy the lower end eyepieces ? I see it here. Whether it’s due to the lack of funds or just different opinions of what we are seeing, we all have different expectations/priorities when it comes to our optics.
 
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CMB

Well-known member
In my case, I haven't owned the Pentax scope in close to a decade, so those eyepieces didn't exist :)

I'm just commenting that the XW views were brilliant back in the day when I had it.... not at all in doubt that even better options exist now.

While I do agree it would be nice to have more options, the fact of the matter is that the modern crop of zoom eyepieces are no longer "substandard" or much of a "sacrifice" vs fixed eyepieces for field use. And even if there is arguably still a small optical sacrifice at a given magnification, the versatility and convenience FAR outweighs it for a field user (birder, hunter, etc).

I'm pretty confident nobody who uses the Kowa 25-60x WA zoom feels like there's any sacrifice in clarity, FOV, or sweet spot size. Sure maybe there's some extra barrel distortion on the low end or maybe a dip in eye relief in the middle of the range, but the convenience more than makes up for it as a field instrument.

Carrying multiple eyepieces and changing them in the field is a huge pain. Every time I've tried it I hated it, and I would never want to do it when I'm out in the field birding. Extra stuff to carry, potential for getting dust in the optics, etc.

For many types of birding the versatility of switching magnifications *without* having to change the eyepiece is of enormous benefit. You can spend 95% of the time with a very convenient, wide angle 25-30x view and then wait, what's that shorebird over there? and boom, you're at 50-60x and can make the ID. No muss no fuss.

Of course not everyone uses their scope in the same way, and if you're mostly doing stationary viewing from your deck or using the scope for astronomy, then having multiple fixed eyepieces and changing them is no big deal. But *in the field* it is a really big deal, so it shouldn't be any surprise that a MASSIVE increase in convenience and versatility is preferred by most end users to a slight increase in optical quality. That was true 10-20 years ago when zooms were clearly inferior, and the fact that modern wide angle zooms have come so far in quality is why the zoom has basically killed the fixed EP in contemporary birding scopes.


You bring up some very good points, and mostly I agree with you - especially about the advances of zoom eyepiece quality from some companies, and most certainly about their overall convenience in the field.

But...

That improved quality definitely comes at price, and even at that price many manufacturers are still lagging in terms of eye relief. Correct eye relief is a critical physical characteristic needed to use a scope properly. It doesn't matter how convenient a zoom is out in the field if you can't see through it properly.

With most zoom eyepieces the eye relief is not constant through the zoom range. The eye relief on most zooms drops in the middle magnification area. Typically that middle magnification area is what people will use most - and it has the least amount of eye relief.

For example...

Suppose you are someone who needs 20mm of eye relief (E.R.) to have the full FOV of the scope.

The Kowa 25-60 zoom you mentioned has 17mm of E.R. at 20mm. At 30x, 40x, and 50x the E.R. is less than 17mm. 30x, 40x, 50x are magnifications that will be used the most, but in some ways they are the least useable because they have the least amount of E.R. For someone who needs 20mm E.R. this zoom is like looking through narrow tubes, is not comfortable, and pretty much takes the scope out of the running as an option. For $700 (US) we should expect the optics to be good, but unfortunately those good optics don't compensate for the lack of the E.R.

Kowa's answer for long E.R. users? Kowa's fixed LER (Long Eye Relief) eyepiece with 32mm E.R. You don't have your choice of magnifications. You get around 26x depending on the model of your scope.

I could only find one company that makes a zoom eyepiece with 20mm E.R. through the entire zoom range. It's the Swaro ATX/STX modular unit and costs $2,300 (US). Then you have to buy the objective lens on top of that.

  • The Swarovski non-modular zoom has a max 17mm E.R. (~$580 US).
  • Zeiss does not provide E.R. specs for their eyepieces ($800 US).
  • Leica's 25-50x WW Aspheric ($870 US) has a max 19mm E.R. Leica does not state if this is across the full zoom range or at the ends of the range.
  • Nikon's Monarch based 20-60 MEP (~$300 US) has 15.3 - 16.1 E.R.
  • Nikon's Monarch based 30-60W MEP (~$545 US) has 14.2 - 15.2 E.R.
    (Nikon offers a fixed eyepiece with 18.5mm E.R. that is 30x on a 60mm scope, and 38x on an 82mm scope)
  • Meopta's MeoPro 2-60x80 HD (~$1,500 US) has a max 18.5 E.R.
  • Vortex's Razor HD 27-60x85 (~$1,500 US) has 16.7 - 17mm E.R. (Vortex does offer fixed eyepieces with long E.R.)
  • The Pentax SMC zoom (~$360 US) has 18-22mm E.R. and has a 1.25" astro eyepiece barrel. It is the best of the bunch in terms of E.R. (not including the Swaro modular system), but optically is not in the same category as the Swarovski, Zeiss, Leica, or Kowa. While the E.R. range one of the best out there, someone will still run into a situation where it restricts their viewing at often used magnifications.
  • Vixen's $200 16-48x zoom has a max 19mm of E.R., and they don't give the specs for the range of E.R.
  • The Baader Hyperion 8-24mm Mark IV zoom (~$290 US) has 16mm - 19mm E.R.
  • The Berlebach 8-24mm zoom with lanthanum glass ($~219) has a max 19mm E.R., and again no specs for the range of E.R.

This is a small example of the research I did to try and find a solution that would work for us. Right away the limited E.R. of many zooms eliminated a lot of scopes as possibilities.

At this point, for people who need long E.R., fixed eyepieces still appear to be the best way to meet the need, but they are disappearing. Unfortunately current zoom eyepieces are creating a hole in terms of workable scope options for some people.

For this reason I would be very sorry to see the Pentax PF series, and the Celestron Regal M2 series, scopes go out of production (I'm not saying they are, so nobody start any rumors to that effect). They provide a viable alternative for people who need long E.R. by allowing one to use astro eyepieces, and do so at a reasonable price point.
 
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Alexis Powell

Natural history enthusiast
United States
...Suppose you are someone who needs 20mm of eye relief (E.R.) to have the full FOV of the scope.
The Kowa 25-60 zoom you mentioned has 17mm of E.R. at 20mm. At 30x, 40x, and 50x the E.R. is less than 17mm. 30x, 40x, 50x are magnifications that will be used the most, but in some ways they are the least useable because they have the least amount of E.R. For someone who needs 20mm E.R. this zoom is like looking through narrow tubes, is not comfortable, and pretty much takes the scope out of the running as an option. For $700 (US) we should expect the optics to be good, but unfortunately those good optics don't compensate for the lack of the E.R...

I don't disagree w/anything you wrote, and I'd like to see more scopes that fit astro eyepieces for other reasons besides, but I do hope that you (and anyone else in the same situation, reading this) tried the Kowa zoom. I usually like to have 18 mm eye-relief for full-size eyepieces, so I was concerned that I might not be comfortable with the Kowa zoom across its range. I was pleased to find that it works for me without any issues, in fact, I find it generously comfortable. I think the spec on it was measured very conservatively. It's the first zoom (apart from Swarovski's latest) for scope that I've found to be comfortable.

Another thought for those needing lots of eye-relief--consider whether your glasses could be designed differently. A stategic choice to allow the lenses to fit a few mm closer to the eyes can open up many options in the world of optics. I wear glasses with big lenses, similar to aviator style, but slightly different shape such that they fit significantly closer to my eyes than would a standard aviator.

--AP
 

mayoayo

Well-known member
The İssue of eyeglasses has Been asking for a subforum for years... Or at least a thread.. People (2 or three) discuss watches on the field, but not birding friendly RX eyeglasses!!
 

Alexis Powell

Natural history enthusiast
United States
The İssue of eyeglasses has Been asking for a subforum for years... Or at least a thread.. People (2 or three) discuss watches on the field, but not birding friendly RX eyeglasses!!

Agreed! There is so much to discuss related to fitting, bifocal/progressive etc design options...

--AP
 

LesR

Well-known member
Eye relief is an issue with me, as a glasses wearer, as I need at least 18mm for binoculars and scopes. My first scope was a Celestron Regal 65, after reading many favourable value for money comments on here, with the bundled zoom which had 18-20mm eye relief. Great scope for the price but wanted a wider view than the zoom projected. I bought a Baader Hyperion eyepiece, all 20mm eye relief, 13mm - approx 30x - and was really pleased with the view, so added a13, 17 & 21mm Hyperion to my collection. After about 18 months upgraded to the 80mm Regal 80 which, when paired with the Baader Hyperions, gave an excellent image and view. Many felow birders compared it favourably with far higher priced scopes. After a couple more years, and an incurable neck problem, I had to sell the angled scopes. I bought a straight Pentax PF 65ED with XW14 ep and also used a Celestron zoom I had and the Baaders. Great little scope and no more neck pain. I was limited to scopes I could buy because of the short eye relief and lack of being able to use astro eye pieces, because I certainly prefer the wide views of the XW14 and Baaders.
I make sure my varifocal glasses fit as close to my eyes as possible, to get the maximum eye relief, every time I buy some new ones.
 

Tringa45

Well-known member
Europe
[*]The Berlebach 8-24mm zoom with lanthanum glass ($~219) has a max 19mm E.R., and again no specs for the range of E.R.
[/LIST]

Berlebach Optics? Has someone been taking their name in vain?

CMB, What I think you are disregarding is the relationship between AFOV, eye relief and eye lens diameter. If you don't have much AFOV, you don't need much eye relief.
The 25-60 Kowa zoom has a 26 mm eye lens and I have measured its AFOV above 50x as 69° so even if you can't see the field stop, you are still going to see quite a lot with your glasses on, as Alexis pointed out .

John
 

CMB

Well-known member
Following up on what both Alexis and John posted about the relationship of eye lens diameter, apparent field of view (AFOV), and impact upon eye relief (E.R.). Here's some quick info on the specs of the Pentax setup mentioned, and how it plays out for one individual in terms of viewing.

I hope that people will provide correction if anything is not right. The reason for posting this is to learn, and provide information for those who deal with difficult eyeglass prescriptions.

The Televue Delos eyepiece used on the 80mm scope:
- Eye lens diam: 38mm
- E.R.: 20mm
- Published AFOV: 72°
- Eyecup rubber eyeguard height: 5.5mm
(the rubber eyeguard is attached to the top of the height adjustable eyecup)
- Eyepiece magnification in scope: 35x

A 38mm diameter eye lens is a large eye lens.

When the individual with glasses views through this eyepiece, with the rubber eyeguard up the individual sees the full black circular hard edge around the FOV. If the rubber eyeguard is folded down so it is flush with the top of the eyepiece, the individual is too close and experiences kidney beaning/blackouts.

The rubber eyeguard is 5.5mm. This eyepiece's combination of large eye lens diam and AFOV allows the individual to see the full FOV with 14.5mm of E.R (20mm eyepiece E.R. - 5.5mm eyeguard height = 14.5 E.R.). With this eyepiece the full 20mm of eye relief is too much and is not needed.

The Televue Delite eyepiece used on the 65mm scope:
- Eye lens diam: 25mm
- E.R.: 20mm
- Published AFOV: 62°
- Eyecup rubber eyeguard height: 5.5mm
- Eyepiece magnification in scope: 35x

This eye lens is 13mm smaller in diam than the Delos.

When the individual with glasses views through this eyepiece they need to have the rubber eyeguard folded down (so it is even with the top of the eyepiece) in order to see the full black circular hard edge around the FOV. If the rubber eyeguard is up, the individual is too far from the eye lens and is not able to see the black circular hard edge around the FOV.

With this combination of eye lens diam and AFOV, 20mm of E.R. is needed to see the full FOV. The 14.5mm of E.R. with the rubber eyeguard up is not enough for the individual to see the full FOV.


The combination of eye lens diameter and AFOV has a measurable impact on the E.R. needed to see the full FOV.


Applying this to a zoom eyepiece.

As John pointed out in the previous post, the Kowa 25-60x zoom has an eye lens of 26mm. That's extremely close to the Delite's 25mm eye lens diameter (only 1mm larger), so it makes for a nice comparison.

The E.R. numbers I could find for the zoom range of the TE-11WZ eyepiece are from measurements posted by Kimmo (kabsetz) here on Birdforum:
16mm @ 25x
15mm @ 30x
14mm @ 40x
15mm @ 50-60x

The AFOV for the TE-11WZ ranges from 60° @ 25x to 79° @ 60x. John measured 69° AFOV at 50x. From 25x-50x the AFOV is 60°-69°

We know with this individual that using the Delite with an E.R. of 14.5mm gives the individual less than the 62° FOV, and with 20mm E.R. they can see the full FOV. Using the Kowa E.R. numbers above, it's reasonable to say that from 30x-60x the individual in this discussion will not be seeing the full FOV through the Kowa scope. And a reduction in the FOV is what the individual experienced when working with the scope out in the field.
 
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Sancho

Registered User
Supporter
Thanks to all. I abandoned the idea, and pulled the trigger on a Zeiss Victory Diascope 65mm with the 15-45ep. It's described as new, boxed etc. How it survived seven years unsold is anyone's guess but we'll see how it fares when it arrives!
Well the Zeiss 65mm had to go back to the Naughty Step for a refund. Couple of internal marks. So I'm taking the excellent advice proferred here and using my Cleyspy scope carrier for the 'big' Meopta. Thanks again to all who helped.
 

ModiK

Member
Sri Lanka
Hi all,
I am hoping to get a Pentax XW 10mm for my 65ED ii for seawatching. I already have their zoom EP. Can anyone give comments on the improvement of quality from the zoom to the XW10. How does it compare to a high end model, say like Swarovski ? Support much appreciated.
Cheers!
 

jring

Well-known member
Hi all,
I am hoping to get a Pentax XW 10mm for my 65ED ii for seawatching. I already have their zoom EP. Can anyone give comments on the improvement of quality from the zoom to the XW10. How does it compare to a high end model, say like Swarovski ? Support much appreciated.
Cheers!

Hi,

first of all, welcome to BF!

The Pentax XW series of eyepieces has a cult following in astro circles for its edge to edge sharpness, wide (but not super wide) 70 deg afov and good eye relief even in fast instruments (like the Pentax spotters they were designed for).
I would expect the view to be as good as it gets with your body. Btw, have you star - tested your scope?
Joachim
 

ModiK

Member
Sri Lanka
Hi,

first of all, welcome to BF!

The Pentax XW series of eyepieces has a cult following in astro circles for its edge to edge sharpness, wide (but not super wide) 70 deg afov and good eye relief even in fast instruments (like the Pentax spotters they were designed for).
I would expect the view to be as good as it gets with your body. Btw, have you star - tested your scope?
Joachim
Thank you very much for the quick reply. Yes, I read many reviews about it on astronomical forums and most are pretty good. Still I cannot find how it goes with a seabirder, and how much it compete with high end optics.
And, nope I have not star-tested my scope, but read about it and will certainly test it out.
-Moditha
 

jring

Well-known member
Hi Moditha,

you can expect a noticeably wider apparent field of view than with the zoom at all magnifications. The Pentax zoom is fairly narrow from about 40 deg afov at the low mag end to a tad below 60 deg at the high mag.

So if your current setup delivers a crisp but a bit narrow view at 40x, you'll get an equally crisp but a lot wider view with the XW10.
It might be a tad brighter too due to less surfaces, but the question remains whether that is perceivable outside of a lab - probably not...

How will it compare to a current alpha at 40x - probably quite well due to its wider view. But of course with a good example of a current alpha and a wide angle zoom, the alpha owner can crank it up to 50 or 60x if the seeing permits and that close-up view will have its charms too...

Joachim
 
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GeorgeL

Well-known member
I have the 20, 14, 10, & 7mm XW eyepieces and they all perform extremely well on both my Pentax 65 & 80mm scopes. I don’t own the zoom EP so I don’t have the basis for comparison.
i also have a few 82 degree Explore Scientific EP’s which also perform well, but with noticeably shorter ER.
 

ModiK

Member
Sri Lanka
Hi Moditha,

you can expect a noticeably wider apparent field of view than with the zoom at all magnifications. The Pentax zoom is fairly narrow from about 40 deg afov at the low mag end to a tad below 60 deg at the high mag.

So if your current setup delivers a crisp but a bit narrow view at 40x, you'll get an equally crisp but a lot wider view with the XW10.
It might be a tad brighter too due to less surfaces, but the question remains whether that is perceivable outside of a lab - probably not...

How will it compare to a current alpha at 40x - probably quite well due to its wider view. But of course with a good example of a current alpha and a wide angle zoom, the alpha owner can crank it up to 50 or 60x if the seeing permits and that close-up view will have its charms too...

Joachim
Thanks for your comment.
Well with the 10mm I will get 39x mag. and with the 14mm I will get 28x. With my current zoom EP up 30x quality is okey yet it has a narrower FOV. Sometimes it makes it harder to trace up a bird flying few km off, seen, and called by a fellow birder due to this narrow FOV. By 40x the zoom EP loss more light and therefor I think the best choice would be the 10mm as it will give more field + mag.
 

ModiK

Member
Sri Lanka
I have the 20, 14, 10, & 7mm XW eyepieces and they all perform extremely well on both my Pentax 65 & 80mm scopes. I don’t own the zoom EP so I don’t have the basis for comparison.
i also have a few 82 degree Explore Scientific EP’s which also perform well, but with noticeably shorter ER.
Wow, great collection!
Have you used them for seawatching?
 

jring

Well-known member
Hi,

from what I heard about the view being ok up to 30x only, I would strongly recommend to at least test whether you can get an easy to find point of best focus with a crisp image at 60x on a cool morning... or do a star test, best late night / very early morning before dawn.

You want to minimize the effect of heat haze aka bad seeing...

Otherwise, the image at 40x is probably not going to noticeably brighter with the XW10. With today's multicoatings even 10 more surfaces (as in 5 more elements or groups) add up to maybe 3 to 5% light loss which I don't think can be seen outside of a lab...

Joachim
 

ModiK

Member
Sri Lanka
Hi,

from what I heard about the view being ok up to 30x only, I would strongly recommend to at least test whether you can get an easy to find point of best focus with a crisp image at 60x on a cool morning... or do a star test, best late night / very early morning before dawn.

You want to minimize the effect of heat haze aka bad seeing...

Otherwise, the image at 40x is probably not going to noticeably brighter with the XW10. With today's multicoatings even 10 more surfaces (as in 5 more elements or groups) add up to maybe 3 to 5% light loss which I don't think can be seen outside of a lab...

Joachim
Hi,
Thanks again for the suggestions and comments. Much appreciated!

Moditha
 

GeorgeL

Well-known member
Wow, great collection!
Have you used them for seawatching?
No, I have not them for seawatching.
I’ve had the EP’s for my telescopes, primarily.
For my 65mm Pentax I like the 14XW. Also, the Explore Scientific 11 & 14mm. I sometimes favor the ES eyepieces over the XW’s for their compact size, especially when hiking.
 

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