What is a panorama?
Panorama is an unfortunately over-used word. As far as I am concerned a panorama is an unusually wide picture that shows at least as much width-ways as the eye is capable of seeing, if not a greater left-to-right field of view than we can ever see (e.g. it shows 'behind you' as well as 'in front'). Cinema has exploited wide images which fill more of the viewer's peripheral vision in order to enhance the immersive effect of films. Now panoramic images are being used for virtual reality too and increasingly in other simple roles such as the navigation on a website.
If you were to display the same image on a TV screen as in a Cinema screen you could describe the difference by saying that the two screens have a very different aspect ratio. What this means is that the ratio of the image width to the image height is very different. Widescreen films available on DVD and video-cassette are often in 16:9 aspect ratio (which equates to 1.78:1). By comparison cinema images are (often but not always) slightly wider at 20:9 (2.22:1).
A 360-degree panoramic image shot with a standard 35mm lens has an aspect of approximately 57:9 but when taken with a wide-angle lens (e.g. 18mm) it becomes approx 4:1 or, to use comparable units, 57:14. Understandably it will often incorporate far more distortion and, when projected or viewed flat, can be a confusing or even unlikable image. When you use a wide angle lens you simply capture more vertically and of course the most you can capture is 180 degrees (to the verticals). Such a picture is typically referred to as a spherical panorama and has an aspect ratio of 2:1 (360 x 180 degrees). It can also be stored in cubic format, but to the end user this will have the same effect as a spherical panorama: the only difference is how the picture is stored because the viewer will project the image, distorting it back into an image that looks 'normal' to us.
|16:9 aspect (widescreen TV)||20:9 aspect (Cinema)|
|57:9 aspect (360 degrees)|
|57:14 aspect (360 degrees, wide angle 18mm lens)|
|2:1 aspect (360 x 180 degrees)|