STEP BY STEP instructions for photographing sphericals.
Equipment: Digital Camera, Tripod, Fisheyelens, head for mounting the camera to the tripod, hot-shooe bubble level.
The first thing we are going to do before even leaving home to photograph a panorama is to carefully mount the camera in the "rig" this is the panorama head which holds the camera. the rig need to securely hold the camera sideways for a vertical view of the world, and at the same time let the entire setup rotate around the fisheye lens nodal point. The nodal point is the optical center of a lens. In the case of the fisheyelens it is right about in the middle of the lens element protruding out of the front of the lens. Study the section on Nodal point before proceeding.
Once you have the nodal point set correctly it is time to make sure the entire rig is level. First setup your tripod on a firm floor. (no... your bed or rug carpet will not do for this.) Carefully make sure that the tripod head is 100% level, do this by placing a level on the top of the head. Once you are happy that the head is level, mount the panorama head on the tripod head, next mount your camera with the lens in the correct nodal point... then put a bubble level in the hot-shooe on the camera and make sure that the camera is level when mounted on the level tripod. If not. make addjustments until the panorama head is screwed tightly together and is entirely level and straight when the camera is mounted in the correct position. Notice that the camera must be perfectly level. Otherwise the results when we stitch the panoramas will be rather funny looking.
Next it is time to think about how we are going to use the fisheye camera. There are a number of ways you can obtain the same results.
2 Shots around. The original way is photographing 2 spherical fisheye images 180 degrees apart. Because the fisheye lens covers more than 180 degrees, these two images will create a perfect spherical panorama. This technique also work well with areas where there are people moving, since it is pretty easy to ensure that nobody moved along the edge of the images.
3 Shots around. As you probably have noticed, the edges of the fisheye image is pretty distorted, this technique provide better details all the way around by using the less distorted center of the images, for this technique you turn the camera 120 degrees between each picture. This is my favorite technique.
3 Shots around+ 1 straight up. Same as the previous tehnique, but with one added picture straight up in the ceiling. The up shot is particularly important if you are photographing interiors where the top of the image is critical, such as a church where the ceiling is decorated beautifully and people might want to study the details by zooming in. The extra image add the same advantage as the extra image around, it provides more details on the edge of the other fisheye images. Remember when you tilt your camera it need to be perfectly aligned with the lens in the nodal point as before.
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