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Pentax XF 12's in my Lunt 100's

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#1 Jeelan

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Posted 11 January 2017 - 12:29 PM

After my recent exposure to Pentax XF 8.5mm eyepieces, I ordered and recently took delivery of the Pentax XF 12’s and yesterday I finally got a chance to try them…

 

I really wanted to see how they compare to the Televue Delite 11mm’s with a view to selling the Delites if the XF’s are as good…

 

targets were some glob and open clusters around ETA Carinae and the moon.

 

ERGONOMICS - These eyepieces are significantly smaller and lighter than the Delite 11’s. The XF’s come in at around 150g each which is next to nothing. Achieving focus in the Lunt 100’s was not an issue with plenty of focus travel left in either direction.

 

_DSC1468_zpsa9qnvjqj.jpg

 

They are par focal with the 8.5’s.

 

Comfort wise i’ve had to remove the outer barrel of the Delites to make them comfortable. While this worked, I never enjoy having to modify an eyepiece to be able to use it (that’s part of the reason I’ve since been considering the XF’s) The XF’s on the other hand fit my eyes perfectly straight out of the box. The eye guard is a twist top with 3 stops between being being fully extended and fully retracted.

 

_DSC1467_zpsffij0cs3.jpg

 

Eye relief is generous - the XF literature puts it at 18mm. I’m dont wear glasses so this is plenty for me. Once i found the most suitable position on the eye guard, eye placement became easy with no blackouts or kidney beaning when rolling my eyes around the FOV.

 

I cant say the Delites are any LESS comfortable in the way I use them however this is with parts of the eyepieces removed. Factory standard, the Pentax’s are definitely more comfortable to use for binoculars/binoviewing for me.

THE VIEW - The XF’s are 60* FOV and the Delites are 62*. To my eye the slight difference in FOV between the two was in line with the slightly higher magnification of the 11mm (50x vs 46x on the XF).

 

_DSC1469_zpsqngvkv4z.jpg

 

Comparison in the Lunt 100’s was done over several hours in both bino mode (same eyepieces in both barrels) and telescope mode (different eyepiece in each barrel for direct comparison)

 

Contrast is equally superb on both eyepieces with the background being presented equally dark.

Other than this, colour representation was also excellent. The moon looked identically white in both eyepieces.  Stars also presented similarly however I thought the view through the XF’s showed a bit more intensity if that makes sense.

 

CA was the one that surprised me. On axis both show no CA whatsoever, however when looking at the Moon off-axis, probably in the last 15% of the FOV, a faint purplish line appears at the edge of the moon in the Delites. The XF’s on the other hand show a clear break with the dark background giving a nice clean edge to the Moon. This really surprised me as I was expecting similar performance from both.

 

To compare the similarity between the 2 eyepieces, I also had my Swarovski ATS 80 spotting scope out with the 25-50x eyepiece. Viewing the moon through this showed nil CA, however the colour of the moon was noticeably warmer which (in my experience) is typical of the Swaro eyepiece in astro viewing.

 

I then moved to a couple of open clusters (NGC3532 below ETA Carinae, and the Southern Pleiades)

On axis stars were equally sharp in both eyepieces. Focusing on the XF was also a pleasure as the stars seemed to “snap” into focus. On the Delites i tend to hunt for the focus a bit more. Its hard to describe and ultimately a very tactile experience.

 

Off axis was a bit different. The XF showed some mild FC in outer 10-15%. When stars were sharp in the centre of the field, the edge softened. If i brought the edge of field into focus, the centre would soften marginally. In the Delites the field remains sharp to the edge. I have read varying reports about this characteristic in the XF 12’s so really wanted to see for myself. Given my experience last night, it wasn’t as bad as I had imagined it to be. Given i view on-axis, its something I can live with.

 

_DSC1473_zpstfaorufg.jpg

 

_DSC1476_zpsuo3emb57.jpg

 

I’m on break for a few days from tomorrow so should have access to dark skies. I plan on taking the Lunt 100’s and these eyepieces so will test some more, however prima facie if my experience continues to be as per my comments above, I’ll be adding the XF 12’s to the collection and moving the Delite’s on.

This gives me a set of Denks in 21mm and 14mm and the XF’s in 12mm and 8.5mm.

 

I have the APM 120’s on order so most likely I’ll keep the Denk 21’s in the Lunt 100’s to give those wide 2.5* views at 26x mag.

 

I’m think of leaving either the XF 12’s or Denk 14’s in the APM 120’s - the XF12’s will give me 55x or the Denk 14’s will give me 43x.

 

The 8.5's will be used once every now and then to push the magnification higher if the need is there..

 

cheers
Jeelan


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#2 ckwastro  Happy Birthday!

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Posted 11 January 2017 - 02:04 PM

Very nice report, thanks!  I've been debating the XFs for a couple years now, for use in my binovoewer.  Every report I read conveys very good to excellent performance so I'm running out of excuses for not pulling the trigger!


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#3 G.Richard

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Posted 11 January 2017 - 02:31 PM

I'm using the XF 12 in my binoviewer and found them to be excellent ep's for that purpose also.  Now I'm considering adding the 8.5 to my bino pairs.   My other pairs are 20mm swa Burgess and 6.8mm uwa Meade series 4000 that I use in my Carton 60mm f16.8 lunar scope.  Thanks for the excellent report on these under used ep's. 


Edited by G.Richard, 11 January 2017 - 02:38 PM.

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#4 Jeelan

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Posted 11 January 2017 - 07:06 PM

The XF's really are a hidden gem in the eyepiece world when you can consider the quality of the image they deliver vs the price they go for...

 

Each XF PAIR cost me about two thirds of the price of a single TV Delite.

 

I'm really glad there are other people also using/considering these fantastic eyepieces.

 

cheers

Jeelan


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#5 Chopin

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Posted 11 January 2017 - 10:14 PM

Very nice report, thanks!  I've been debating the XFs for a couple years now, for use in my binovoewer.  Every report I read conveys very good to excellent performance so I'm running out of excuses for not pulling the trigger!

Kerry, get off yer arse and buy the darn eyepieces already!


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#6 Chopin

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Posted 11 January 2017 - 10:24 PM

The XF's really are a hidden gem in the eyepiece world when you can consider the quality of the image they deliver vs the price they go for...

 

Each XF PAIR cost me about two thirds of the price of a single TV Delite.

 

I'm really glad there are other people also using/considering these fantastic eyepieces.

 

cheers

Jeelan

Jeelan, I really enjoyed the read. I've been using pairs of the XF12's and XF8.5's for a couple years now. I feel like I need to stop preaching their greatness, so I'm happy to see you putting in some good words for them. As for the field curvature, I agree entirely with your findings.  I guess for me, I'd rather have softened edges than CA. They compare favorably against my T6N's, and honestly I think they are the best value in mid-wide field eyepiece on the market. Boy, do I wish they made other focal lengths...!


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#7 rockethead26

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Posted 11 January 2017 - 11:20 PM

B&H has the 8.5 XF's right now for 158.40 each. You need to request that they email you the lower price (right on the product page). I just picked up a pair. Heck of a deal.

 

Jeelan, thanks for bringing these to my attention.


Edited by rockethead26, 11 January 2017 - 11:48 PM.

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#8 ckwastro  Happy Birthday!

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Posted 12 January 2017 - 09:50 AM

 

Very nice report, thanks!  I've been debating the XFs for a couple years now, for use in my binovoewer.  Every report I read conveys very good to excellent performance so I'm running out of excuses for not pulling the trigger!

Kerry, get off yer arse and buy the darn eyepieces already!

 

You know me bro!  Too much thinking!  :gve:

 

Look how long it took me to re-acquire a larger scope!  :bangbang:  :bangbang:  :bangbang:



#9 ckwastro  Happy Birthday!

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Posted 12 January 2017 - 09:51 AM

Having said that, how is the edge performance on these? 12mm in particular since I'd buy that set first.  Thanks!



#10 Jeelan

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Posted 12 January 2017 - 09:10 PM

Thanks for all the positive comments...

 

I'm in the same boat as most of you in that I spent a few month deliberating about these as there's simply not enough info around on the eyepieces...

 

hopefully if a few of us get a chance to test them we can keep this thread alive with enough info to allows to make a more definitive decision..

 

that being said, I havent had a chance to test any more as its overcast and rainy where we're at. Scenery & wildlife are stunning but weather for star gazing just isn't on my side at the moment...

 

cheers

Jeelan


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#11 ckwastro  Happy Birthday!

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Posted 12 January 2017 - 09:23 PM

Having said that, how is the edge performance on these? 12mm in particular since I'd buy that set first.  Thanks!

Sorry Jeelan, just went back and caught the paragraph about off-axis performance & mild FC. Thanks.



#12 Jeelan

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Posted 13 January 2017 - 04:54 AM

Crystal clear skies tonight so hopefully I can get a bit of stargazing done. 

 

will post some comments tomorrow.

 

photos will have to wait until I'm home. Internet / phone signal is patchy where we're staying so Im doubtful I'll be able to upload any photos.. 

 

cheers

jeelan 


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#13 Jeelan

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Posted 13 January 2017 - 06:22 PM

So I had about an hr last night before the moon came up after which I no longer had dark skies due a full moon..

 

still very happy with the XF 12's... these are definately a keeper for me.

 

i browsed predominantly with them last night, swapping to the Denk 14's for reference.

 

still no CA on the edge of the moon and mild FC present when I looked for it. Focusing on th centre of the field it was as sharp as th Denks.

 

i browsed a couple of larger open clusters where the FC became a bit more obvious but moving the binos back and forth a bit helped with that as I brought whatever I was viewing into the centre of the FOV.

 

face placement was so easy that comparatively even the Denks (my favourite eyepieces) started to feel bulky and awkward.

 

On another note the xf's weren't too bad for day use either - I suspect this legacy may come from their use in Pentax spotting scopes...

 

cheers

Jeelan 


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Posted 13 January 2017 - 06:42 PM

Thanks for the update! They do sound very nice. I've also been considering that APM 100 or 125 binoscope. I'm guessing the XFs would be nice there as well. 



#15 Jeelan

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Posted 13 January 2017 - 09:49 PM

Well my intention is to us th Denk 21's on the APM 100's as a lower power wide angle instrument for Milky Way sweeping. I've got the 120's on order so was thinking of using either the Denk 14's (43x mag) or the Pentax XF 12's (55x mag) on the bigger binos for more detailed and specific observing.

 

cheers

Jeelan 


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