[awo425]

The FF 14's of Canikon don't have em (at least the Nikon doesn't, that I'm sure of hehe)

I don't have 14 mm FF Canon lens, I did use 16mm MC Zenirar , FF lens indead on a film body.

With this 16 mm lense you have field of view nearly 180'.
How are you going to use front filters on a 180 degree field of veiw lense is a mystery for me. For exactly the same reason Zenitar was equipped with small filters on a back element of the lens.

Pentax DA 14/2.8 is not a FF lens and I guess this is why it has filter thread, but comparing it's characteristics to 14 mm FF lens is like comparing apples and oranges.
Do we have front filter thread on any of the 10mm APS-C lenses?

[jeffkrol]

I don't have 14 mm FF Canon lens, I did use 16mm MC Zenirar , FF lens indead on a film body.

With this 16 mm lense you have field of view nearly 180'.
How are you going to use front filters on a 180 degree field of veiw lense is a mystery for me. For exactly the same reason Zenitar was equipped with small filters on a back element of the lens.

Pentax DA 14/2.8 is not a FF lens and I guess this is why it has filter thread, but comparing it's characteristics to 14 mm FF lens is like comparing apples and oranges.
Do we have front filter thread on any of the 10mm APS-C lenses?

An 11-18mm zoom will take a 77mm filter. sigma 10-20, the same:
Sigma - Lenses
Tamron SP AF 11-18mm F/4.5-5.6 Di-II LD Aspherical (IF) Lens Review - photo.net
fisheyes don't count
Sigma Lens 10mm F2.8 EX DC Fisheye HSM Lens for Nikon SLR in Camera Lenses and Lens Adapters at JR.com

[Duplo]

Correct, since they are Full-frame, these lenses have much more glass than a APS-C 14mm (like the Pentax prime) Check out the Canon 14mm f/2.8 and Nikon 14-24mm f/2.8, they are HUGE compared to the Pentax. And because of the curved front element, they can't take filters (easily...)

Yep I can attest to the 14-24 being a fairly large wideangle lens, but couple to a D3 it actually handles very very well... I really like that combo a lot.
And the 14mm end is insanely well performing, but only way to use filters is to handhold a very large filter in front of it.

Wow. This is news for me

So if the 14/2.8 from other brands have no filter thread, how do they use polarizer, ND filters, etc? Even the cokin filters require an adaptor ring of some sort which screw into the filter thread?

Well it depends on the format.
When used on APS-C I have seen adaptors build too at least the 14-24/2.8 from nikon.

On 35mm I simply do not use filters with it.
I dislike polarizers on ultra wide angle...
In 35mm terms I am very reluctant to use a polarizer from 28mm and down, as there is quite a risk of uneven effect from it, due to the wide angle of view.
ND filters can be done but it is handheld and not easy at the wide end...

It is a limitation of the lens, but a small price to pay for the performance it delivers.

[soccerjoe5]

I believe I've seen square filter holders that attach onto the lens barrel instead of using filter thread adapters. (Think I saw them on the lee site)

That should help with using them on lenses without threads if you don't want to handhold

[soccerjoe5]

No, just a more expensive kind of grass

Hahaha this one just cracks me up!

[Gus]

Nilkon's 14-24 is a phenomenal lens in most respects for architectural work, edge to edge sharpness and very well controlled distortion (extremely well considering the angle). A true winner when coupled with a D3 or a D700.

[Duplo]

I believe I've seen square filter holders that attach onto the lens barrel instead of using filter thread adapters. (Think I saw them on the lee site)

That should help with using them on lenses without threads if you don't want to handhold

Yeah but I have yet to hear someone using it succesfully on the 14-24 at the wide end with a 35mm camera...
Unfortunately...

Hahaha this one just cracks me up!

And it is true...

It is a different grass too though.