kieboom

Regarding the noticeable transitions, there don't appear to be any clouds in the sky.

My guess is that the exposure setting changed in moving from left ot right. One clue is that the wall of the building on the right is much lighter than the wall of the building in the middle, even though they are at pretty much the same angle to the sun. If the exposure was the same for each, the walls would be equally bright, and the sky as well.

I'm very impressed with the photo stitching in WLPG. So far, I've only done one panorama, 4 shots taken handheld and expsoure on automatic. WLPG was able to blend the photos almost perfectly. Previous experience with other stitching programs was not as good.