On CTF Refinement

Dear All,

Will you please explain the function of cryosparc CTF Refinement? With the T20S datasets, I first run the CTF Refinement and got the refined mrc output file. With the refined mrc output file, I runt he homogeneous refinement, and did not find any resolution improvement in comparison with the homogeneous refinement without the CTF Refinement step.

I am looking forward to getting your reply.

Best wishes,


Hi @Flemming,

When using CTF refinement, it is important to note that it is not guaranteed to result in a resolution improvement. It’s effect depends strongly on the resolution of your starting reference, the amount of beam tilt/trefoil/tetrafoil present in the dataset, and the signal-to-noise ratio. Please refer to our tutorial on using local and global CTF refinement on our guide for more practical details and references to the underlying theory: https://guide.cryosparc.com/processing-data/tutorials-and-case-studies/tutorial-ctf-refinement.


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