Which UWA for Nikon full frame

[JohnBrew]

5. I tested a new-out-of-the-box Zeiss 21mm f2.8. It was soft on the edges at f8 at 100'. Put simply,I wonder if it's a flat-field lens? Everyone raves about it, but I will not buy one. 
- N.

Nick, sorry you ran into a problem with the Zeiss 21. I purchased one several weeks ago after renting for one week. I haven't shot it all that much since getting it so when I read about your problems I ran out and did quite a few tests this afternoon. Mine does not have the problem you experienced. I have one extreme corner which is a little soft in close up shots, but its not anything I can't live with. I find it to be an exemplary optic and I guess you were bit with sample variation. OTOH, I rented a 45 PC-E, liked it and bought one only to run into sample variation and the lens was unusable. I sent it back and did not accept an exchange. Once bitten...

[Peter McLennan]

Depending on your use, the Samyang 14mm f/2.8 UMC is a very good lens.

I'd love to try this lens but my remote location precludes testing or renting.  MF and aperture don't scare me.  Are you aware of any reliable tests on this lens?

thanks!

Peter

[Rhossydd]

I'd love to try this lens but my remote location precludes testing or renting.  MF and aperture don't scare me.  Are you aware of any reliable tests on this lens?

DXO give it a stellar rating (for the Canon mount version at least).
There are plenty of other tests of the Canon mount version I can add, but haven't looked for any Nikon reviews myself.

I just got it in a Canon mount yesterday. Whilst I haven't had time to give it a really serious test, the initial shots I've taken and looked at suggest everything written about it is correct. The possible exception is quality control, as mine appears to have a correct focussing scale, so it might be even better than some early reports suggest.
Using a correction profile in Lightroom deals with all the curious distortions.

[Peter McLennan]

Gotta love it.  Superwide, high quality images and a great price.  I look forward to your ongoing experience with this lens. 

[Lightsmith]

You cannot do better than the 14-24mm f2.8 zoom lens. It is sharper than prime 14mm, 18mm, and 24mm lens I have used from Canon and Nikon. The only lens that I have used that is its equal is the Nikon 15mm UW lens.

I shot with the 16-35mm f4 for a week and realized it was not going to provide the IQ I was used to getting with the 14-24mm f2.8. If I wanted a lighter UWA and or one that would accept a screw on filter I would get the 17-35mm f2.8 lens.

The 16-35mm f4 is not nearly as bad as the 12-24mm f4 Nikon zoom lens but it is not anywhere near as good as the 14-24mm zoom - not unexpected considering the difference in price.