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Focal length dialog box
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You use the film size dialog box to describe the focal length of the lens used to capture the images. For example, if you use a 28mm lens, you should enter a focal length of 28mm.
The degree of image warping required to stitch the panorama is defined by the ratio of the film size to the focal length. For digital cameras, use the 35mm equivalent focal length and enter 24mm by 36mm for the film size.
The focal length dialog box offers the following controls:
Focal length (mm)
Enter the focal length of the lens in millimeters.
Fine tune
Pressing this button causes The Panorama Factory to automatically compute the focal length from the stitched panorama. Before using this function, you must have created a panorama with a focal length close to the correct value. The Panorama Factory will be unable to compute the focal length if the initial value is too far from the correct value.
Film plane
Use this control to describe the type of camera you used to take the pictures. Sorry, fish-eye lenses are not supported yet.
Flat (conventional camera)
Your camera has a rectilinear lens and a flat film plane. Use this choice for ordinary cameras; for 35mm and APS panoramic cameras that mask the top and bottom of the frame; and for wide-view planar panoramic cameras such as 6x17 format cameras.
Curved (swing-lens, etc.)
Your camera has a rectilinear lens and a cylindrical film "plane." Use this choice for swing-lens and rotational panoramic cameras.
Max step (mm)
The initial focal length change tried by The Panorama Factory when fine tuning the focal length.
Min step (mm)
The final focal length change tried by The Panorama Factory when fine tuning the focal length.
You can fine tune the focal length in two ways. If you fine tune when the stitched image is in the current image pane, The Panorama Factory will examine all overlap regions to determine the best focal length. This is very time consuming. It’s better to fine tune from a single, representative overlap region.
To fine tune from a single overlap region, you must use the Fine tune button when that overlap region is open. To open an overlap region, click on the top or bottom edge of an overlap rectangle when the stitched image is showing (see the Stitch command). Once the overlap region is open, you can activate the Focal length dialog and use the Fine tune button to compute the focal length according the single overlap region
Revised: October 13, 1999