Camera precalibration

[AVisser]

I recently did a survey using a precalibrated camera. When processing in Photoscan, however, when I fix the calibration under Tools->Camera calibration the results are way worse than when I do not fix the calibration. The difference in error is about one order of magnitude.
I suspect this is because if you fix the calibration Photoscan has less degrees of freedom moving things around to obtain a proper fit. Thus, is it better to precalibrate and get large errors, or do not precalibrate and basically do not know what changed?

[mwsurvey]

Did you ever get any response from this question AVisser? I have just started using agisoft and have the same concern.