Cloud Nine

This is my first tilt-shift shot. It's still taking a little getting used to setup and focusing, but so far I'm really excited about all the possibilities. For this shot I had the camera vertically oriented and quickly shifted the lens train right/left 10mm each to create a 3 shot image.
5D Mark III
24mm
1/5 sec @ f/11
ISO 50
Thanks for any comments and critique that you may have.


Techie question:
In my head I was expecting to be able to perfectly overlay the three shots without using Photomerge because the projected image was just being cast over different parts of the sensor without changing anything except horizontal shift, but it didn't really work out that way. While the shot alignment was much better than traditional panoramas, it still needed some manipulation to merge perfectly. Anyone know why this is? Is it because the aperture location is shifting slightly relative to the scene or is the sensor not perfectly flat and causing the minor distortion? Just curious if either of these theories make sense.