Took my first city shots at night and noticed something peculiar. I shot at 18mm with my Sigma 18-35, a lens that has very little distortion if any. I noticed that when the tallest building was in the centre of my shot, it appeared straight. However, when it was at the edge, it was clearly bent. The building was still perfectly straight, but not 90 degrees to the ground. I had to adjust the image 4.3 degrees to correct for this.
The city I was shooting had a large river running through it, and thus all the buildings lined up to an edge. This edge was not straight from my building, perhaps explaining why the tall building appeared crooked.
Is my experience normal? For presentation, would you correct it so the largest building was straight?
Thanks for your help.