Thanks, Frank. Did you find the corners soft at both 14mm and 24mm focal lengths?
Hi Michael, the corners improve with decreasing focal length. This is a bit unfortunate for me, since I mainly use the lens between 18 and 20mm. 14mm is quite extreme for landscape and I use 14mm more for indoor shots or closer views.
Below are three examples at 24, 18 and 14mm. (Nothing particularly inspiring, just the lawn in my backyard, which hopefully provides enough details.) Shown is the lower left part of the frames. I cropped the pictures in a way that about 1/4 of the horizontal and vertical parts of the full frame are shown (a 1/16 of the total image area). RAW developed in LR4 without any adjustments, i.e. sharpening was at 25/1.0/25/0. No output sharpening.
The goal of this unscientific test was to get as much as possible into focus. I placed the focus distance of the lens at about 12m to maintain good sharpness at infinity (not shown in the crops below) using f/8. Of course the foreground improves when I focus closer, but then the sharpness at infinity declines. One could argue that a focus distance of 12m is too far for this test. My experience was that you lose more at infinity than you gain in the foreground when focusing closer. Anyhow, this was a compromise...
Probably others tested the lens in different situations and this explains their verdict. The goal was to find out how the lens is doing for the so-called near-far images with a wide vista and some interesting foreground. I know that a TS would be better for this, but this is what I have. BTW, I had access to a second sample which behaved in the same way.