lensfun
0.3.1.0

Struct to save real focal length, which can depends on the (nominal) focal length. More...
#include <lensfun.h>
Public Attributes  
float  Focal 
float  RealFocal 
Real focal length. More...  
Struct to save real focal length, which can depends on the (nominal) focal length.
float lfLensCalibRealFocal::Focal 
Nominal focal length in mm at which this calibration data was taken
float lfLensCalibRealFocal::RealFocal 
Real focal length.
When Lensfun speaks of “focal length”, the nominal focal length from the EXIF data or the gravure on the lens barrel is meant. However, especially for fisheye lenses, the real focal length generally differs from that nominal focal length. With “real focal length” I mean the focal length in the paraxial approximation, see http://en.wikipedia.org/wiki/Paraxial_approximation. Note that Hugin (as of 2014) implements the calculation of the real focal length wrongly, see http://article.gmane.org/gmane.comp.misc.ptx/34865.