I always use portrait mode for taking panorama shots.

A lot of great panoramas are made with long lenses and the camera in portrait mode. It allows you to zoom in on your subject, stitch a half-dozen shots together and maintain detail. Very effective method. 

Back in the late 1970s, I adored my OM1 film camera! Such a simple and easy rig for street, and I was living on the Main Street of a small town...