Nice work, aureliandan! The blending and HDR processing looks essentially invisible, which is very good!
Looks like you managed to keep the camera level left to right but slightly tilted to camera upward which created a mild keystone effect on the height of the building. Are you making use of any kind of bubble level on your tripod or camera? If not, I'd suggest that you do. Very mild key-stoning can look very natural but anything beyond "mild" will look off.
Thanks! I've just received the TS-E 17 so this is the first image
The camera used was a Canon 40D (1.6x) and I was very close to the building, with the landscape orientation, in order to keep the top of the building in frame I had to tilt the camera up taking care not to exaggerate. Now I understand what a FF camera can do in combination with a TS-E 17mm lens so my next body will not be 7D but 5D MII
Anyway your comments and samples from this thread was of great help, thank you for that!
I have a geared head (Manfrotto 410) with bubble level and another 3 way bubble on top of the camera so the first step is to keep everything leveled.
The same building in portrait orientation with 8mm shift: