Parallax
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When you shoot panorama frames, there are two effects that can cause major problems for the stitching software: Parallax and Lens Distortion.

1. The Parallax effect

Parallax results from the same physical law that allows us to see 3-dimensional. If you close one eye and rotate your head, you will notice that objects change their relative position to each other. Since we actually have two eyes, we can see 3-dimensional without the need for head movement. For a camera, which is turned in order to shoot panorama frames, the same effect applies. If two objects on bordering frames lie in the stitch area, and if these two objects are shifted due to the camera movement, then the stitching software may have problems finding the corresponding characteristic points in the two frames. In the best case, this can cause object ghosting, frame distortion or blurring.

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"Ghost mountain" resulting from Parallax
 

How to avoid Parallax  
 
Parallax comes from the movement of objects in 3D. If everything in the scene is approximately the same distance from the lens, or very far away, parallax will not occur, or at least be minimized. This is why handheld panoramas from a mountain top tend to work quite well - everything is far away from the camera, and the distances are very large compared to the tiny distance between the nodal point and the point of rotation.  

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Another way to reduce parallax, is to use a special tripod, which allows you to rotate the camera around the nodal point of the lens.
 

2. Lens Distortion

Wide angle and fisheye lenses have a tendency to warp the edges of the picture. The distorted view causes the stitching software to become confused when trying to glue the frames together. The end result again is overlapping ghost images, similar to the parallax syndrome.

icon_tip Tips for shooting panoramas

CodedColor PhotoStudio tries to correct the parallax effects by warping bordering frames, until the characteristic points overlap best. The downside is, that linear objects like trees, buildings or horizons may appear distorted in the stitched panorama. So, it's best to try and avoid parallax in the first place:
 
·Try to use a tripod.  
·Make sure the axis of rotation is perfectly vertical.  
·Try to move the nodal point of the lens over the axis of rotation. You may need to construct a special mounting plate for this.  
·Try to exclude near objects, if you are making a long distance panorama.  
·Try to use a focal length of around 50 mm, in order to reduce lens distortion. Stay away from wide angle lenses.  
·Make sure you have overlapping regions of at least 20-30% (stitch area).  
·Avoid frames that are taken against the sun, causing reduced contrast.  

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