Pentax XF question

[Troy]

Under the eye twist cup is there a thread of some kind?
My Pentax xo eyepieces have a thread and was Wondering if the xf eyepieces where the same.

[Kunama]

Originally Posted by Troy

Under the eye twist cup is there a thread of some kind?
My Pentax xo eyepieces have a thread and was Wondering if the xf eyepieces where the same.

The XF eyecup can be removed to reveal a 30.5mm 0.5 pitch thread for adapters. The eyecup itself uses a 31.9mm 0.5 thread.

[Troy]

Thank very much Matt, how do they perform visually?

[Kunama]

I've only had mine for a few weeks, but managed to try it in each of my scopes. The XF8.5 is excellent, very sharp across the field, no apparent lateral colour in my refractors, more neutral than the LVW in tone. I think it is a beautiful little eyepiece. The XF12 is equally good in everything except that it exhibits some field curvature. I use them for planetary viewing so the field curvature in the 12mm is of no consequence for me.
I think they are both "keepers"

I think they have been around long enough to prove themselves, there are a few reviews within several threads. I know that John (ausastronomer) has the 8.5 and likes it. Like most things Pentax they are very well made. I believe they employ one or more lanthanum glass elements although that in itself doesn't matter much if they are not mated to the correct glass types and well figured.

They are very light and compact, a blessing in this age of monstrous eyepieces.

[David Niven (David Niven)]

Hi Troy,
The Xf8.5 is my favorite ep in my collection.
It is sharp to the edge and provides ample eye relief, beside being very light weight. It's build quality is very high like the other Pentaxes.
This one is a keeper!

[Troy]

Sounds good thanks Matt, David

[eeyore (David)]

Hi, do you know if the XF is parfocal with the other pentax EP, specifically the XL? Cheers.

[Camelopardalis (Dunk)]

Erm...stick it in after one of the others and see if it needs refocusing!

[Kunama]

Originally Posted by eeyore

Hi, do you know if the XF is parfocal with the other pentax EP, specifically the XL? Cheers.

I haven't used the XLs in many years and have only tried the XW a few times so can't help with that. My eyepiece collection consists of the full Vixen LVW set (which are parfocal), a Hyperion 31mm Aspherical and the 2 Pentax XFs.

[JethroB76 (Jeff)]

My 8.5XF is the one EP that I regretted selling. I replaced it with an Ethos 8mm, but I still regretted it.
Great EP