Taking pictures for use with Photomerge
Your source photographs play a large role in panoramic compositions. To avoid problems, follow these guidelines when taking pictures for use with Photomerge:
Overlap images sufficiently
Images should have an overlap of approximately 15% to 40% of the image area. If the overlap is less, Photomerge may not be able to automatically assemble the panorama. However, keep in mind that the images shouldn't overlap too much. If images overlap by 70% or more, it can be difficult to work with them, and blending may not be as effective. Try to keep the individual photos at least somewhat distinct from each other.
Use a consistent focal length
Avoid using the zoom feature of your camera while taking your pictures.
Keep the camera level
Although Photomerge can process slight rotations between pictures, a tilt of more than a few degrees can result in errors when automatically assembling the panorama. Using a tripod with a rotating head helps maintain camera alignment and viewpoint.
When photographing a panoramic scene from a high place, the natural inclination is to keep the horizon level in the viewfinder. However, this actually produces a noticeable rotation between images. Try using a tripod to keep the camera level when taking photographs in this situation.
Stay in the same position
Try not to change your position as you take a series of photographs, so that the pictures are from the same viewpoint. If you walk to a new position while taking photographs, you'll likely disrupt the continuity of your images. Using the optical viewfinder with the camera held close to the eye helps keep the viewpoint consistent. Or try using a tripod to keep the camera in the same place.
Avoid using distortion lenses
Lenses, such as fish-eye lenses, that cause noticeable distortion to the image can interfere with Photomerge.
Maintain the same exposure
Avoid using the flash in some pictures and not in others. The advanced blending feature in Photomerge helps smooth out different exposures, but extreme differences make alignment difficult. Some digital cameras change exposure settings automatically as you take pictures, so you may need to check your camera settings to be sure that all the images have the same exposure.