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If the Pentax XW 30mm & 40mm came back, would you buy?....

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#101 25585

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Posted 13 August 2019 - 11:43 PM

Maybe some 40mm XLs will go on the market. XLs in any FL are rare, on ebay anyway. 



#102 Sarkikos

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Posted 14 August 2019 - 06:26 AM

I predict that many will buy and many will resell.  The smarter buyers will wait to buy the resells.  I guess I'm not that smart.  :shrug:

 

:grin:

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#103 25585

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Posted 14 August 2019 - 07:31 AM

I predict that many will buy and many will resell.  The smarter buyers will wait to buy the resells.  I guess I'm not that smart.  shrug.gif

 

grin.gif

Mike

Me neither.

 

So what's the competition? APM UFF 30mm, ES68 34mm, Vixen NLVW 30mm  and TV 35mm Panoptic v XW 30 keeping to longer eye relief.

 

ES68 40mm, 41mm Panoptic, Vixen 42mm LVW v XW40.

 

So for those wanting a 40mm may buy & keep moreso than those wanting a 30mm.

 

But which would sell to owners of what telescopes? Slower scopes may be fine with less expensive, lower profile makes, while faster F5 & less might be too fussy or already what their owners consider best.

 

Who is the "ready and waiting" market? People who missed out before &/or are unwilling to pay insane pre-owned prices perhaps. Pentax XW collectors/devotees possibly. Those who have tried other eps and not found a satisfactory weight or other aspect, maybe more likely?

 

Pentax needs to get their pricing right, with the XW 30 especially. Certainly no more than a 35 Panoptic, though I expect it to be higher than an ES68.

 

Personally, curiosity is my weak point, and quest to find my perfect eyepiece for each focal length - usable eye relief for my glasses, exit pupil ease, adjustability, edge performance, no astigmatism, fine at F5.

 

40 first, 30 second in order of buying. My favourite 40s currently is the LVW. 30s its equally APM and 35 Panoptic, but being lighter the APM is used more and is an honourary Morpheus next up from the 17.5 in my case.


Edited by 25585, 14 August 2019 - 01:56 PM.

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#104 Sarkikos

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Posted 14 August 2019 - 12:03 PM

For me, the competition against the 40 XW will be the 40 Titan-II ED and the 41 Pan.  I already have those two.  I doubt if I'd let the 41 Pan go.  Even though it's heavy and bulbous, the correction across the field is just too good.  

 

So the competition will be between the 40 XW and the 40 Titan-II ED.   

 

Heck, I might just keep all three.

 

Mike


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#105 25585

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Posted 14 August 2019 - 01:58 PM

For me, the competition against the 40 XW will be the 40 Titan-II ED and the 41 Pan.  I already have those two.  I doubt if I'd let the 41 Pan go.  Even though it's heavy and bulbous, the correction across the field is just too good.  

 

So the competition will be between the 40 XW and the 40 Titan-II ED.   

 

Heck, I might just keep all three.

 

Mike

What scopes would you use the XW in? 



#106 Grahaml

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Posted 19 September 2019 - 07:11 PM

I think I'll stick with the shorter xws , a friend did have the 30 and  sold on for a 31 t5 many years ago, I have a pan 35  atm which is very sharp  across the field  and comfortable now i have the extender for it.



#107 John Fitzgerald

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Posted 19 September 2019 - 07:16 PM

I find that the longer focal lengths are the eyepieces I use the least, so, no, I wouldn't buy.



#108 25585

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Posted 20 September 2019 - 07:07 AM

For me its curiosity. The quest to find my perfect eyepiece of each focal length or TFOV. Eye relief, pupil retention, optical performance, relaxing viewing. 

 

No 30s or 40s there quite yet, but close. It's not greed or OCD, just curiosity. So good things have been said about these XWs. And other makes.

 

It may be that the 30mm falls short of my UFF, NLVW, Panoptic - but at least I will know. The 40 has an easier task. I don't like it's Panoptic rival, find my SWA too heavy (but more comfortable than the 41), the 42 Vixen LVW will be closest competition - but I want to know the XW first hand. Roll on 2020!          


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#109 havasman

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Posted 20 September 2019 - 12:26 PM

no



#110 Scott99

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Posted 20 September 2019 - 12:42 PM

It may be that the 30mm falls short of my UFF, NLVW, Panoptic - but at least I will know. 

IMO there's no "perfect"...it's a zero-sum game.  The XW's aren't as "sharp" to the edge - i.e. keeping stars as points - because they don't employ rectilinear distortion.  It's a feature not a bug!  laugh.gif laugh.gif

 

It's a design choice.  You want the stars as points, you get a Nagler 31mm, UFF, etc.  But then the Pleaides stars will be moved from their natural positions.  When you pan around, you will see a non-realistic "bending" of the starfield.  You physically cannot have your cake & eat it too!    These eyepiece have different characteristics, there won't be one that can do it all.

 

Coatings & glass quality are a separate criteria - using better & more expensive ones can improve color fidelity & contrast - two strong points of the XW line.  It was pretty easy to see all these factors at play when comparing my 35mm Panoptic with the 2 XW's.  

 

I actually changed from wanting to see stars sharp at the edge to preferring the view in the XW's instead.   But people who insist on seeing stars as points at f/5 won't like the XW's.  The same issue of whether to have rectilinear distortion comes up in high-end binos for the birdwatchers too - everyone has their own preference.  In birdwatching they call it the "rolling ball" effect.


Edited by Scott99, 20 September 2019 - 12:57 PM.

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#111 Oscar56

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Posted 20 September 2019 - 02:19 PM

Like many I will probably wait to see what the price will be. I have the XW series from 20mm through to the 7.5XW. For me it’s all about their comfort.

I secured a 35Pan as my finder EP which is a similar weight to the existing 30XW and 40XW. I find it almost as comfortable as the XW series. It will be a tough decision to ditch the 35Pan.
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#112 areyoukiddingme

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Posted 20 September 2019 - 02:38 PM

It took me quite awhile to compete the set of XWs, and had to resort to making random offers to people who I knew had those focal lengths.

 

I'd be curious to compare the quality of the old and new, particularly the 30, which I think is a tad weaker than the 40.

 

But I don't think I would be sufficiently curious to buy a new one to find out.


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#113 Starman1

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Posted 20 September 2019 - 04:16 PM

IMO there's no "perfect"...it's a zero-sum game.  The XW's aren't as "sharp" to the edge - i.e. keeping stars as points - because they don't employ rectilinear distortion.  It's a feature not a bug!  laugh.gif laugh.gif

 

It's a design choice.  You want the stars as points, you get a Nagler 31mm, UFF, etc.  But then the Pleaides stars will be moved from their natural positions.  When you pan around, you will see a non-realistic "bending" of the starfield.  You physically cannot have your cake & eat it too!    These eyepiece have different characteristics, there won't be one that can do it all.

 

Coatings & glass quality are a separate criteria - using better & more expensive ones can improve color fidelity & contrast - two strong points of the XW line.  It was pretty easy to see all these factors at play when comparing my 35mm Panoptic with the 2 XW's.  

 

I actually changed from wanting to see stars sharp at the edge to preferring the view in the XW's instead.   But people who insist on seeing stars as points at f/5 won't like the XW's.  The same issue of whether to have rectilinear distortion comes up in high-end binos for the birdwatchers too - everyone has their own preference.  In birdwatching they call it the "rolling ball" effect.

Confusion of terms.

The "rolling ball", or "globe" distortion is when a large amount of angular magnification distortion is present and rectilinear distortion is reduced to a minimum.

When AMD is reduced to a minimum and RD is left large, I believe that is sometimes called "fish bowl" distortion, or just "bowl" distortion.

 

In the way they express themselves, RD is a radial distortion, which stretches radial lines out near the edge (pincushion) or compresses the radial lines near the edge (barrel, which is far less common).

AMD, on the other hand, compresses or expands objects as they near the edge.

 

One way to think of it:

Pincushion RD:  ) | ( is a straight line crossing the field

Barrel RD:  ( | ) is a straight line crossing the field

AMD would show as x  X  x  as the x crosses the field  or as X  x  X if of the opposite sign.  The first example is far more common, hence the appearance of the field rolling over a ball.

 

Which is worse for daytime use in a spotting scope?  RD, I think--you can tolerate a slight size difference, but not straight lines bending.

Which is worse for nighttime astronomy?  AMD, I think, because you want the objects, double stars, etc. to stay the same size as they cross the field.

 

And the manufacturers seem to agree with that.  The eyepieces with the least RD come to us from spotting scope backgrounds.

 

However, I've seen and used the XWs a fair amount--they have a lot more RD than AMD, so I think they are fine for astronomy use.

At 70°, if they were free from RD, they'd have a LOT of AMD, and they don't.  Distortion percentages grow with apparent field.

The reason they have astigmatism is just that they weren't formulated to handle f/5 and faster light cones.  You can see from the optical graphs that only one or two focal lengths really minimized astigmatism.

 

One way to think of it, though, is that distortion is distortion, regardless of the form.  If you prefer a distortionless field, i.e. an orthoscopic field, then keep the apparent fields small, like 40-50°.


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#114 punk35

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Posted 20 September 2019 - 06:14 PM

So, how do the XL’s stack up against the XW? Basically the same, besides the small fov difference? IE: If I’m looking through an XL, would the view be the same as looking through an XW but with a slightly smaller field? 


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#115 25585

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Posted 22 September 2019 - 11:43 AM

This post https://www.cloudyni...e-50/?p=7620156 comparing the Tak LE 40 & Pentax XW 40 is interesting. No apologies for the refractor porn!



#116 nicoledoula

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Posted 22 September 2019 - 12:57 PM

NO, I wouldn't unless I already owned all the XW's except the 30 and 40mm and wanted a complete set. 



#117 25585

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Posted 22 September 2019 - 01:21 PM

I only have the 10 XW (& a 5.2 XL). Other makes for other FLs. In fact the 10 was bought as there was no Vixen LVW 10mm, and the Pentax was recommended.

 

The 30 & 40 are not to complete a set for me, but last stage in a quest. Either ir both will be sold if I am dissatisfied.  


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#118 gnowellsct

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Posted 22 September 2019 - 08:30 PM

No, because the XW Buddah already blessed me with a complete set.


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#119 gnowellsct

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Posted 22 September 2019 - 08:40 PM

If it is really true that the XW 40 and XW 30 are coming back I might buy them just to have a backup set. I have an unopened XL 7 and I don't even know why. I don't remember buying it.

Perhaps to give my estate executor something to ponder.

#120 earlyriser

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Posted 23 September 2019 - 12:59 PM

I probably would to see if they could displace the Nagler 31 I have now. The eye relief and field of view of the XW series seems more in line with the Delos eyepieces I have and love, and they weigh a lot less than the Nagler. Having a 40mm eyepiece would also maximize my exit pupil when using the paracorr. 


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#121 gnowellsct

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Posted 23 September 2019 - 07:28 PM

I probably would to see if they could displace the Nagler 31 I have now. The eye relief and field of view of the XW series seems more in line with the Delos eyepieces I have and love, and they weigh a lot less than the Nagler. Having a 40mm eyepiece would also maximize my exit pupil when using the paracorr. 

I prefer them to the N31 but then again I'm not fond of any of the Nagler 82 degree offerings.  That's what drove me to Pentax in the first place.

 

In my particular situation, I typically have a c8 or a c14 with a 92 mm apo on top, or a 130 mm apo with the 92 mm apo on top.  So I get to have a lot of fun playing with different apertures.  

 

The catch is when you want wide fields in both scopes.  Sometimes I use the XW 30 and XW40 but sometimes I pull out the Leitz 88 (30 mm) to use instead of the 40mm XW.  It's somewhat less field, but I like it as an ocular.

 

The reason is personal, my own astigmatism can be limiting at lower magnifications.  I *do* have a dioptrx which works on the XW 30 and XW 40, but I have found that if I am sharing the views with other people having an eyepiece that others can't use (because of the dioptrx) is a source of aggro.  

 

Greg N


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#122 gnowellsct

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Posted 23 September 2019 - 07:30 PM

People should be aware you can use the dioptrx on the XW30 and XW40.


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#123 Starman1

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Posted 23 September 2019 - 08:15 PM

The information in the link is quite wrong.

You can use the DioptRx on the XW eyepieces--they do tighten down just fine.

You don't have to hold it down with the eyecup over the DioptRx.

They tighten down on any diameter from 41 to 44mm.

Because the top of the eyepiece is a cylindrical thread (no lip), it helps to press down on the DiopRx ring as you tighten it down.

You can even pick up the eyepiece holding only the DioptRx afterwards, and the DioptRx will not slip off.

The DioptRx similarly tightens on the Baader Morpheus eyepieces.

 

Edit:

Or do the 30mm and 40mm not have the same 43mm thread on the top of the 3.5-20mm sizes?

I was under the impression they had the same 43mm camera adapter thread.


Edited by Starman1, 23 September 2019 - 08:43 PM.


#124 John F

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Posted 24 September 2019 - 01:36 AM

Oscar56, on 20 Sept 2019 - 12:19 PM, said:

Like many I will probably wait to see what the price will be. I have the XW series from 20mm through to the 7.5XW. For me it’s all about their comfort.

I secured a 35Pan as my finder EP which is a similar weight to the existing 30XW and 40XW. I find it almost as comfortable as the XW series. It will be a tough decision to ditch the 35Pan.

I also have a 35Pan that I use as my low power/finder eyepiece.  I acquired it three years ago as a smaller size and significantly lighter weight alternative to the 31Nagler.  I'm 71 now and have to use eyeglasses while observing so the 24mm of eye relief that the 35Pan provides works very well for me.  When I recently read that Ricoh is now planning to re-introduce the 30mm & 40mm XWs back into the marketplace I was pleased to hear that and was seriously considering getting the 30mm version because its TFOV is 94% as wide as the 35Pans but its power is 17% higher and it should provide better contrast and a darker sky background than the 35Pan does.  Also good is that its weight is not significantly heaver than that of the 35Pan.

 

However, I recently came across some physical size specs for the 30mm XW and was disappointed to learn that its upper barrel is just as wide as that of the 41Pan and its height is just a tad lower than that of the 41Pan.  The center tray area on my tripod where I keep my eyepiece set when I'm observing isn't very large so that factor limits how many and what size eyepieces I can comfortably use with my telescope.  I tried a 41Pan for about a year and gradually grew frustrated with it (not because of its optical performance) because its disproportionally large size made it more difficult for me (at night) to reach over (or around) it when I wanted to retrieve (for use) a different eyepiece.  While the 35Pan is not a small eyepiece it is small enough that I don't have that problem with it so I've decided I'm just going to keep and continue using it as my lowest power/finder eyepiece. 

 

However, for someone who already has a 30mm ES82 or a 31mm Nagler and wishes that there were a viable smaller and lighter weight alternative to it then I think that the 30mm Pentax XW eyepiece certainly warrants serious consideration as a viable alternative. 

 

John Finnan  


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#125 earlyriser

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Posted 24 September 2019 - 10:17 AM

This thread might be of interest to those considering the 30 XW, assuming it becomes available again. 

 

https://www.cloudyni...s/#entry2178675


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