[Matthew Saville]

Zooms with big range are seriously overrated. Too many compromises. You really only need 2 or 3 of the focal lengths anyway (two ends and a mid point). A difference of 20mm is a really nice range for a lens to have. It's enough that the optical design remains strong yet long enough for the lens to be flexible.

That is why I'm happy to carry around a "short zoom" like this, as long as BOTH ends are something I could use. In this case, having a 14mm and 20mm f/2, if it weighs anything like the new 11-20mm f/2.8, would be a bargain both optically (hopefully) and weight-wise.

Oppositely, if the zoom fails to cover a range that I actually need, it becomes utterly useless compared to a prime within that range. Take for example the new Sigma 24-35 f/2. Considering its >2lb weight, I am extremely un-interested in lugging it around unless I absolutely need both 24mm and 35mm at my fingertips. And my feeling is, compared to an f/1.4 prime or a 24-70mm f/2.8, as both a wedding photographer and an astro-landscape photographer I'm totally un-interested in the 24-35mm f/2. Now, if it had been a 20-30mm f/2, or 18-28mm f/2, that would open up a new realm of possibility on full-frame and I might have strongly considered it. If it weighed too much I'd obviously still opt for something lighter for backpacking trips, but it would still be a trophy lens worth owning for serious astro-landscape work.

Thus, IMO the 14-20mm f/2 is a worthwhile investment for a nightscape shooter, especially if you subscribe to the philosophy of it being a 2nd body for 2-3 camera timelapse work.

[ogl]

f2 at 14-20 mm is special thing for special photos IMO....I remember good DA14/2.8's photos wide-opened - very special effect.

[volley]

I got the number from various glass manufacturing technical publications from Schott,Ohara,Asahi,Corning et al. In the glass fabrication industry the most common allowable variance in diameter for a finished lens is 0.05mm+/- as the median figure, the minimal deviance is about 0.1 μm for high precision optics.

Thanks for the clarification, I think we agree that the diameter is probably the least important dimension with no need for accurate machining.
Take care

[RMabo]

Also note that the Pentax 50-135 and 16-50 are weather sealed designs, but the Tokina versions was not.
And yes, Pentax sells a couple of Tamron re-branded lenses made by Tamron - but with Pentax optical coatings and Pentax original lens chip. Pentax had done this since the 90's, do remember the Pentax/Tamron f/4-5.6 (IF)... And then later the 18-200 and never versions.

With Tokina, it was an optical design partnership not productional. Pentax and Tokina has different housing / lens barrels, electronics and AF systems and coatings.
The Pentax branded lenses are made by Pentax in their own factory where other Pentax lenses are made.

Oh, and to my knowledge the Pentax DFA 100 f/2.8 (not the later WR-version) was optically similar to Tokina AT-X Pro 100 f/2.8 Macro. (don't know if was a Pentax patent or Tokina patent for the optics).

[ogl]

Only Nikon and Canon version.

http://www.dpreview.com/news/4439209905/tokina-announces-ultra-wide-14-20mm-...p-sensor-dslrs

[Digitalis]

Only Nikon and Canon version.

I saw that caveat coming.

[Zygonyx]

Well, until K mount is not selling enough to insure third-opticians like Tokina or Tamron enough return on mount adaptation, they won't change their strategy.
Better and less risky for those opticians, to be getting more or less royalties from RI in R&D costs on a small part of their catalogue.

[lesmore49]

For the most part Tokina licensed Pentax's optical formulas for their lenses. The one exception was (is) the DA 12-24, where Pentax licensed Tokina's optical formula. Lens design otherwise was done by each company -- different coatings and different auto focus mechanisms (the 16-50 for Pentax has dual auto focus mechanisms, the Tokina was screw drive only).

Anyway, I think Pentax would have to grow in market share considerably before you see Tokina releasing their new lenses in a K mount, but it still would be nice to see it.

I dunno. I understood that Schneider designed the Pentax 12-24 for Pentax.

---------- Post added 01-01-16 at 05:33 PM ----------

Announced
Tokina announces ultra-wide 14-20mm F2 lens for Canon and Nikon crop sensor DSLRs: Digital Photography Review

Tokina APS-C SD 14-20mm Lens Coming Soon « NEW CAMERA

Will we see the same for Pentax K mount?

It's an F 2, but other than that, I'm more than happy with my Pentax 12-24.

[lytrytyr]

I understood that Schneider designed the Pentax 12-24 for Pentax.

Wasn't that just Samsung's re-brand of Pentax lenses for their K mount GX DSLR's?

[SpecialK]

I thought that Tokina and Pentax still make the 10-17...

My Canon mount Tokina 10-17 says "Japan". Pentax 10-17 was MIV (?). Not sure if the Pentax is the same, but I can use the Tokina from 15-17 on FF - yay.

[starjedi]

Only Nikon and Canon version.

Tokina announces ultra-wide 14-20mm F2 lens for Canon and Nikon crop sensor DSLRs: Digital Photography Review

Sigh!!!

[lesmore49]

Wasn't that just Samsung's re-brand of Pentax lenses for their K mount GX DSLR's?

My understanding...from a British photography magazine a number of years ago...was that Schneider designed the Pentax 12-24.

[Digitalis]

Schneider designed the Pentax 12-24

If that was true, it would be a better lens.

[lesmore49]

If that was true, it would be a better lens.

I have a 12-24 Pentax and have taken thousands of photographs with it. It's a great lens. In fact Popular Photography called it a best in class.

[thibs]

My understanding...from a British photography magazine a number of years ago...was that Schneider designed the Pentax 12-24.

Nope. Tokina did AFAICT.