Ultra Wide Angle lens comparison (Canon oriented, but...)

Although this comparison was done on a Canon 5Dmk2 it still holds a good deal of relevance for other camera platforms. In fact, only one of the lenses tested here is truly native on the camera on which it was tested (Canon TS-E 17f4L). The Samyang 14mm f/2.8 is available in multiple mounts. The other lens in the comparison is an Nikkor 20mm f/4 AI, adapted for Canon with an inexpensive Ebay adapter and a filing down of the AI pin that would otherwise interfere with the mirror.

So if you're a Nikon user please continue reading as the Samyang (and older Nikkor) are both directly usable.

First of all the field of view of these three lenses is obviously different.

Comparing the center performance is fairly straight forward. However to contrast edge performance we would rather compare like elements in the scene so when we look at "edge" or "corner" performance the part of the scene that is at the extremes of the Nikkor 20mm is clearly not so extreme on either the 14mm or 17mm. Of course the 14 and 17 are more extreme focal lengths so we think the comparison does have some basis for being made. We're just not comparing apples to the same type of apples.

Here are the centers of the three, taken at f/11:

And here they are at the left edge:

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