Panorama Advice - Creating and Stitching

Advice on creating and stitching panoramic images.

Creating Panoramic Images

Panoramic Earth shows two kinds of panoramas:
  1. Cylindrical Panoramas - These are the easiest to create, forming an image that is wrapped around like standing in the middle of a cylinder.
  2. Spherical Panoramas - These go both round and also up and down, like standing in the middle of a sphere or bubble. They are great for indoor shots of impressive buildings like churches and palaces.
For both types of panorama, the best results will be achieved using a tripod and panoramic head. Special lenses are available that attach onto SLR cameras to create cylindrical panoramas in a single shot. Many other people use either wide angle of fish-eye lenses to shoot the images. There are numerous packages available to then stitch the images together to create the final panorama.
It is possible to shoot Cylindrical Panoramas by hand, without a tripod, especially when shooting outdoor, scenic images where errors in the overlap are minimized.If you have a digital camera and are able to hold it steady and align one frame with the next then you are ready to begin creating panoramic photos.
It is even possible to get reasonable results shooting by hand indoors, as shown on these inside the Louvre in Paris and the Pantheon at Rome show, but the errors do become much more visible. It is also sometimes possible to rest the camera on a flat surface and rotate it between the shots. This is especially useful in very low light levels where it would be impossible to hold the camera steady for long periods (often measuring in seconds).

Hand Held Panoramas - Some Pointers

Hand held images work best if shooting landscape work where most of the subject of interest is quite far away. Each image should overlap the previous one by about 30%. If possible, the camera should be used in portrait view (so the resulting image is taller than it is wide). It is inevitable that when taking hand held panoramas you will rotate the camera both horizontally and vertically, and with many 'instamatic' type digital cameras this will mean that the usable panorama will be very long and narrow if shot in landscape view. Here are some tips for taking panoramas by hand:
  1. Hold the camera to take the shots as tall and narrow (portrait view).
  2. Shoot at the highest resolution you have. You can always remove data, but not the reverse.
  3. Shoot at the widest angle available.
  4. If possible, shoot in 'Manual' mode setting both the aperture and shutter speeds yourself. Many SLR cameras will allow this.
  5. If possible, take the White Balance setting off 'Auto' and set it for the current light conditions (sun, shade, manual etc). This is available on some SLR cameras and reduces colour variation as you turn around.
  6. Imagine that the ball of one of your feet is the central point for rotation.
  7. Lean back a bit to try to align the camera over the ball of the rotating foot.
  8. Take the first picture,
  9. Rotate on the ball of the foot until you have moved far enough round for the next image (try to leave about a 30% overlap with the previous image).
  10. Take the next shot. Then repeat steps 8 & 9 until all the images have been taken and you are back at the starting point.
Using a monopod can greatly help in taking panoramic images, however the screw mount on cameras is almost always on the bottom which fixes the camera in landscape view to the monopod. It is possible to buy 'L' shaped attachments which then allow the camera to be fixed in portrait view.
The very best results are obtained using a tripod with a special panoramic head attached. These allow you to adjust the camera to minimize the effect of nearby fences moving relative to the background - called the Parallax Effect (see below). Some of these can be quite expensive, and you often get what you pay for. However, it is possible to make your own with little cost. One of the contributors to Panoramic Earth describes how he made his own home made panoramic head very cheaply.
If you end up shooting panoramas then the next thing you will need is image stitching software. Once you have put your images together you can then upload them to the site. The profile of each person who has added images to Panoramic Earth may tell you some information about the cameras and image stitching software used.

Panorama Image Stitching Software

Two widely used image stitching packages available are PTgui from New House Internet Services and Photovista by iSeeMedia. Many modern packages are based upon Panotools which was first written by Prof Helmut Dersch. This set of tools can be quite complicated, and offers an enormous amount of control to the user, but would not be recommended for those starting out.
Once you have created your panorama, you can upload them to Panoramic Earth following the instructions given on our Upload Panorama Page.

Parallax Effect

This is the relative movement of nearby objects against the background as the viewpoint changes. What this means for taking panoramas is that as the camera is rotated objects that are at different distances from the lens will move relative to each other. A lamppost that was to the right of a tree in one shot can appear to the left of the tree in the next because of parallax. The effect is greater the nearer objects are to the camera, and can cause real problems with fences, posts etc that are close by.
Every lens has a sweet point, which used to be referred to as the 'nodal point' but now more accurately called the 'no-parallax point'. If the rotation takes place with the no-parallax point at the centre of rotation, then parallax is removed. When taking hand held panoramas, leaning back slightly over the rotating foot brings the camera lens closer to the no-parallax point reducing errors.
You can see this yourself by closing one eye and rotating your head. You will see the foreground and background move relative to each other because the center of rotation is your neck. The no-parallax point of the image, somewhere in you eye, is forward of the center of rotation which results in your own personal parallax effect. To remove this you would need to rotate around the no-parallax point in your eye. Those interested in reading more on this can see the article on Parallax on Wikipedia.

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