A wider view: Independent Super Wide-Angle lenses comparedBy Ben Boswell - Friday February 01 2013 Lens Review
Alternative Super Wide Angle lenses: Sigma and Zeiss compared to Samyang 14mm f2.8 IF ED UMC Aspherical Nikon
Both Nikon and Canon have 14mm f2.8 lenses in their ranges, at the time of writing neither has been fully tested by DxO Mark, but reviews on both will follow soon. The lenses we have reviewed here are made by independent manufactures and there are others too. Samyang produce a 14mm f2.8 IF ED lens for Nikon and in other mounts too: Canon, Sony A and Pentax, it is well worth looking at, especially in comparison to the Sigma lens.
These three measures show the correctable errors in the lenses and on the basis of these results, you can see that the Zeiss lens is best overall. Of the other two the Samyang is better for chromatic aberration and the Sigma for distortion. The distortion on both the Sigma and especially on the Samyang lenses is irregular, showing corrections that swing from barrel to pin-cushion across the field, for architectural photographs there would be times when an un-corrected image would be completely unacceptable, whereas the Zeiss lens has a more consistent curve, this can be seen in the chart. When you look at the next chart however, the results are quite a shock!
Now the Samyang lens is the best of the three, it scores 18 M-Pix for sharpness, 2 M-Pix higher than the Zeiss lens and double the score of the Sigma. Sharpness is either there or it isn’t so this is an impressive coup for the Samyang, made even more impressive by the fact that it has a price tag less than one sixth of the Zeiss lens and almost half the cost of the Sigma. Taken as a whole the Zeiss Distagon T* 2.8/15 ZF.2 is the best of this group, the images captured with it are going to be better, straight from the camera than those captured by either of the other two. Once you look at value in the equation too, the results seem to favour the cheapest of the bunch, the Samyang 14mm f2.8 IF ED UMC Aspherical, with the addition of some post production from DxO Optics Pro it is likely that the final results would be better than could be achieved from any other independent lens of this focal length.