Panoramas captured in portrait orientation mode will have an aspect ratio similar to that of a capture from the standard camera app in landscape orientation. However, the capture from the Panorama app will be at a significantly higher resolution (e.g. 6344 x 3422 [21.7MP] versus 3552 x 2000 [7.1MP] on the Lumia 925), potentially capturing more detail.
Windows Phone Store description:
Get the bigger picture with Nokia's easy-to-use Nokia Panorama app. Simply take your pictures and the app automatically stitches them into a picture view. When you're done, share your Panorama directly with friends on Facebook and Twitter.
In this latest release you can capture more height by simply using the camera in portrait mode.
Panorama is a free download for Lumia devices from the Windows Phone Store.