I will be honest – doing a comparison between the Nikon 16-35mm f/4.0G VR and the Canon 17-40mm f/4.0L USM was somewhat painful. First of all, the DSLR bodies that I was using did not have the same megapixel count (Nikon D300 is 12 Mp and Canon 50D is 15 Mp) and crop factor (Nikon D300 is 1.5x and Canon 50D is 1.6x). Achieving the same field of view and having similarly sized 100% crops for accurate testing and comparison was extremely difficult and I had to move my setup back and forth to get to a similar size. Even then, I was not able to get the results I wanted in the corners, so I will be focusing more on center performance rather than corners.
The image on the left is Nikon 16-35mm and the image on the right is Canon 17-35mm. Both were shot in RAW with no post-processing in Lightroom besides adjusting white balance.
Let’s take a look at the far corners @ 17mm f/4.0:
The Nikon 16-35mm clearly has both sharper image and better contrast in the corners.
Let’s now take a look at the center @ 17mm f/4.0 where I was able to match the view:
As can be clearly seen, Nikon 16-35mm f/4.0 VR is significantly sharper than Canon 17-40mm f/4.0. When compared at f/8.0 both lenses are very similar in terms of sharpness and contrast. Now let’s see the performance @ 24mm f/4.0:
Again, Nikon 16-35mm is the clear winner, delivering more sharpness wide open.
The final test is both lenses at 35mm:
As expected, there is no change – the Nikon 16-35mm f/4.0 is sharper than Canon 17-40mm f/4.0 @ f/4.0 across all focal lengths.
I did not bother uploading the images at other apertures, because both lenses perform very similarly at f/5.6 and higher and at f/8.0 there is practically no difference between them. The above test is to show that the Nikon 16-35mm is sharper than its counterpart Canon 17-40mm when shot wide open both in the center and in the corners.
The above has been posted to the Nikon 16-35mm f/4.0 Review on the fifth page.