The problem of shooting on a perfectly level platform is that many times angle of view can be very restricted to the lens you use.
For example, let’s say I want to include more sky or some of fog below the mountain horizon. I can’t do it because I would no longer have a perfect level, and therefore the degree of my view starts to shift upward or downward, which makes it difficult if not impossible to stitch images later.
You might argue that I could use a wide-angle lens and crop the image later after merging images. The problem with that method is that you will get a lot of distortion and have to do a lot of cropping later, which reduces the resolution of the image.
Whenever I shoot panorama, I prefer between 50mm-200mm range lens to avoid distortion and to shoot it vertically, so I will have more images to merge together, which will produce a higher resolution panorama.
Camera with Cannon TS-E 45mm tilt and shift lens
Both Nikon and Canon have a “Tilt & Shift” lens from 17mm (Canon only) – 90mm – Canon: TS-E lens (Tilt & Shift for EOS), Nikon: PC-E (Perspective Control Lens). It is a unique lens that allows a photographer to correct point of view by tilting and swinging the front of the lens, or by rotating and moving it up or down.
I found a Canon 45mm TS-E to be a perfect lens for my panorama photography. I could shift the lens upward and downward (+ / – 11 degree) without having to move the camera up or down. Therefore, I could include more sky or foreground below with a correct perspective.
McWay Cove Fall (Big Sur, California) is a good example. The place where I was standing was way too high to have a perfect horizon in panorama. If I were to shoot with a conventional lens, I would not be able to include waterfall below. With the tilt & shift lens, I was able to include the waterfall and the sky as in the image. One thing to be careful is to take a exposure reading (in manual exposure) before tilting or shifting the lens, or you will get an incorrect exposure due to lens barrel shifting the light to the camera sensor/film.