When this option is turned on PhotoModeler automatically finds the optimal set of parameters to solve during calibration based on an iterative processing approach. The default set of parameters is used in the first stages of processing, and if processing fails, certain parameters are removed and processing is repeated. Processing is repeated until the optimal set of parameters is found and calibration processing is successful.
This feature works well when in tandem with the Deviation and Correlation check (see Camera Calibration Options Dialog) where parameters that have high deviations and/or correlations are removed from the calibration automatically. Calibration processing is repeated automatically until a suitable calibration is solved.
If no suitable combination of parameters is found with automatic processing parameter assignment and/or the deviation and correlation check, calibration can fail (this will rarely happen unless there are problems with the calibration project setup, photography factors etc. see Camera Calibration Troubleshooting). You will then want to review your setup, perhaps manually adjust parameters and stages (see Choosing Camera Parameters to Calibrate) and try calibration again.
Note: If the images in the calibration have EXIF data, PhotoModeler uses this data when estimating the Focal Length as a starting point for calibration. PhotoModeler will attempt to verify that the EXIF Focal Length information from the images is valid (it is not correct on all cameras). If the data does not produce reasonable results a warning will appear that will allow you to choose an alternate form of focal length estimation. Also note that PhotoModeler uses other internal checks when EXIF information is not available, so the calibration will also work with images that do not have EXIF information.