Here is a comparison to the Rokinon/Samyang.
The Zeiss is a tad sharper at 2.8, but they are equal by f/4. Though this could be due to TDP having a bad copy.
The Zeiss also has a bit less distortion, but it's also 7% less wide so it's not apple to apples.
I definitely don't see $2,600 worth of improvement.
"The Zeiss is a tad sharper"....LOL..based on the corner resolution in The Digital Picture comparison tool, I would think that you may be able to shoot sharper with a plastic lens rather than the SamYang...at ALL apertures... I don't think it is worth $359. ...but hey whatever makes you happy...you are smiling!!!! Maybe around f/8 the SamYang is tolerable.
I don't know what to make of Bryan's review and/or charts (he has never actually reviewed the lens), although I have been told that there are two variations/optical formulas (older and newer) of this lens, but my own review along with that of others say that the new version is in fact basically as sharp as the Canon 14L and is one of the sharpest wide angle optics available for a Canon lens.
Roger here at Lens Rentals says that he is a big fan of the lens and that it compares favorably with the 14L.
I've used about five different wide angle options, and the copy of the Rokinon that I have is so much sharper at all apertures than anything that I have used before that there is no comparison. I have no doubt that the Zeiss is better still, but as it is about 10x the price...
P.S. The Rokinon blows the Canon "L" wide angle zooms away in sharpness in every detail.
So Dustin...I believe you...do you think that The Digital Picture is using the same lens that you have or something different? I also, really respect Roger at Lens Rental...Did you pay $359 for your lens? ....and it is sharper than the Canon? REALLY?
I have been told since doing my review that there was an earlier version of the lens that lacked the UMC element as a part of the optical formula and was significantly inferior to the newer version optically. That being said, I went and checked Bryan's lens sharpness tool again and his does say UMC. His chart shows a significant difference between the 14L and the Samyang, particularly in the corners. But his results don't seem to match that of other very reliable reviewers, and doesn't agree with my own results, either.
I don't know how to account for his results. I think Bryan is a great reviewer, but I don't feel like his chart results reflect my own experience. His results show that the 17-40L is sharper at equal apertures, but I just dumped my own 17-40L because the results were so inferior to my Rokinon.
Look at these two links from ePhotozine:http://www.ephotozine.com/article/samyang-14mm-f-2-8-ed-as-if-umc-lens-review-19621http://www.ephotozine.com/article/canon-ef-14mm-f-2-8l-ii-usm-lens-review-23412
Of particular interest in their sharpness testing; it unquestionably shows the Samyang as sharper (than the 14LII), even in the corners. Anyway, I can only chart it up to either sample variation or reviewing differences (which illustrates why it is important to read multiple reviews and then form your own conclusions).