Pentax XF 12mm

[andrew63]

Would like some user opinions if anyone has tried them in a refractor of around F7.

I have found the 8.5mm fine. It appears to be ok in fast dobs but possibly has a weakness in refractors. I would be interested in views as thinking of buying one.

thanks, andrew

[dweller25]

The 12mm XF is very good in an F/8.

[great_bear]

I was always too worried about the field curvature to take the plunge. However, since this is worse in the 8.5mm and you've not had a problem with that, then the 12mm should be fine for you. Have you read Amalia von Allmen's well-known shootout article about the 12mm Pentax XF compared with a 12mm Radian? It's a very comprehensive write-up, you can read it here <click>

[andrew63]

Thanks

[crazyjedi]

I've always been very impressed with my 12mm Rad and have no experience of Pentax lenses. The rewiew seems to favour the Pentax offering.

Both Pentax and TV are both rather expensive so how come the big difference in contrast? One would have expected more of an even match.

[great_bear]

It's not so much a bad statement about Radians, it's more that the proprietary Pentax "SMC" coatings are meant to be rather special...

[crazyjedi]

I've heard nothing but good things about the Pentax range so I'm not suprised that they're considered to be excellent but TV are equally revered. Thought it would have been a closer contest is all.

Was considering the Pentax 20mm XW as a future purchase but also wanted the 24mm TV Pan or Meade 24mm SWA but I thought maybe there wouldn't be enough of a difference between the focal length of each EP to warrant two very expensive EP's.

Pentax don't appear to have an EP inbetween the 20mm and 30mm focal length.

[RikM]

I've heard nothing but good things about the Pentax range so I'm not suprised that they're considered to be excellent but TV are equally revered. Thought it would have been a closer contest is all.

Was considering the Pentax 20mm XW as a future purchase but also wanted the 24mm TV Pan or Meade 24mm SWA but I thought maybe there wouldn't be enough of a difference between the focal length of each EP to warrant two very expensive EP's.

Pentax don't appear to have an EP inbetween the 20mm and 30mm focal length.

Same here. I would love a 25mm XW.