"Computes the parameters for using extension tubes.
Requires: 1. original-object-distance, original-image-distance, or original-magnification
2. new-object-distance, new-image-distance, new-magnification, or extension-length
Returns: original-object-distance, original-image-distance, original-magnification, original-bellows-factor
new-object-distance, new-image-distance, new-magnification, extension-length."
"Computes the parameters for using extension tubes.
Requires: 1. original-object-distance, original-image-distance, or original-magnification
2. new-object-distance, new-image-distance, new-magnification, or extension-length
Returns: original-object-distance, original-image-distance, original-magnification, original-bellows-factor
new-object-distance, new-image-distance, new-magnification, extension-length."