Pentax XF 8.5mm & 12mm v Vixen SLV 9mm & 12mm

[25585]

Both Pentax & Vixen SLV cost the same from FLO.

Pentax has (advertised) 18mm eye relief & Vixen (advertised) 20mm.

Pentax has 60 deg fov, Vixen 50 deg.

 

I own the Pentax XW 7mm & 10mm but was looking for...less valuable eps when viewing in the field away from home. Only 2mm difference in eye relief, but t10 deg AFOV. However which is better optically?

[Paul73]

The SLV may only have 50°, but it is a really good 50° (Very near Delos quality which i’m Told is similar to the XW).

Very comfy to use. They are also very light.

And, very cheap.....

I’ve not tried the XF range. Believe that @John has explored both models.

Paul

[Highburymark]

The XFs are great little eyepieces - particularly for binoviewing - light, sharp, good value, clean and contrasty views. Think they'd be much more popular if the range was wider and they'd been marketed to astronomers more actively. Haven't used an SLV, so can't comment on comparative qualities

[rwilkey]

I think I would choose the Vixen SLV for a better overall view and sharp as they come.  The only pain about the Pentax XF is that the fold-up rubber eyeguard comes loose easily and comes off, otherwise the ep is quite good right across the field.

[F15Rules]

Pentax XF every time for me. I've owned both XFs and just the 12mm SLV. I didn't like the latter and returned it to FLO (I know most people like the SLV range though).

The XF is Japan made, has superb mechanics and optics (including Lanthanum element I believe), and is rather like a mini XW or XL.

It has a significantly wider field of view and is sharp to the edge in my scopes (F7.7 & F8). The 12mm has minor field curvature, which didn't bother me personally. The XFs used to have an RRP of £149, so at around £99 now they are excellent value. I would say the build quality is better than the Vixens (and I'm a big Vixen fan, the LVW 22mm is one of my all time favourites).

Regarding the "fold up rubber eyeguard", I wasn't aware the XFs had such a feature..a twist up click lock feature for comfort, certainly, but not fold up as far as I'm aware? The top part of the rotating/twist up cup has a directional arrow to indicate which direction to turn to adjust the cup up or down, so if the cup also folded up it would obscure this? (See photo below, image credit to Microglobe Ltd).

I've certainly never had an issue with that excellent feature?.

Dave

[Louis D]

One thing to consider about the Vixen SLV is that the eyeguard does not retract to be flush with the top of the eyepiece.  This costs the user 3mm to 4mm of usable eye relief.

Personally, I think the 9mm Meade HD-60 is a fine eyepiece.  In direct comparison to my 9mm Vixen LV, the Meade appeared to be better corrected in the center 50 degrees which surprised me quite a bit.  Even at the edge it is nearly free of astigmatism or field curvature.  It's also quite easy to take in the whole view with eyeglasses.  Here's an optical test bench review of it by Ernest in Russia.

Edited February 15, 2018 by Louis D

[rwilkey]

23 hours ago, F15Rules said:

Regarding the "fold up rubber eyeguard", I wasn't aware the XFs had such a feature..a twist up click lock feature for comfort, certainly, but not fold up as far as I'm aware? The top part of the rotating/twist up cup has a directional arrow to indicate which direction to turn to adjust the cup up or down, so if the cup also folded up it would obscure this? (See photo below, image credit to Microglobe Ltd).

Hi Dave, getting my 'eyeguards' mixed up, what I mean is the rubber covering on the twist-up feature (which works perfectly well), unless this is just a odd one that failed quality checks?

[F15Rules]

2 hours ago, rwilkey said:

Hi Dave, getting my 'eyeguards' mixed up, what I mean is the rubber covering on the twist-up feature (which works perfectly well), unless this is just a odd one that failed quality checks?

Ah, I see, well it's possible of course. I've owned 3 XFs and all were fine in that respect, but maybe a bad one got through..

Dave ☺

Edited February 16, 2018 by F15Rules

[Timebandit]

 

Well I love my XW and IMO some of the best eyepieces around. I have never tried the XF, so can't really comment on these .

The predecessor to the SLV ,the NLV is a great eyepiece IMO . It was Japan made and with some great sharp Optics to the edge of field. It's sharpness is Ortho like. But with the fov around 50d  ,  feeling so comfortable and wide due to the large entrance eye lens and combined with around 20mm of eye relief. For the price point the NLV/SLV is one of the best eyepieces i have used for overall comfort and sharpness.

But why are you basically doubling up on the focal lengths? . If you have already got the XW in my opinion the XF or the SLV is not going to best your XW you already own. Take these XW into the field. But just make sure they are in a well padded case ,and after using each one make sure you put the caps on and  put it straight back into the safety of the case( this is what I do). If you take care of your eyepieces there is no reason not to take them with you into the dark site. Eyepieces are there to be used and the XW are some of the best out there, use the best and not alternative. ?

 

 

I hope this helps and has saved you a few ££ , the XW should go with you into the field ?

 

 

[andre2]

Hi, and which of these is the best choice for an alpha- h solartelescope?  ( 12 mm XF or 12 mm vixen SLV for Lunt 60 tilt) thanks.

 

Edited April 18, 2023 by andre2