[ccp4bb] how to estimate the error of unit cell parameters

I wonder how to estimate the errors of unit cell parameters of crystal? Thank you very much!

[ccp4bb] how to estimate bond length error from crystal structure

Dear friends, A zinc atom is located in the active center of my protein. I want to estimate the errors of bond-lengths between the Zinc and coordinated residues in the crystal structure. Who knows how to estimate that errors? Thank you very much!