--XMAG not updated from Relion2.1b

Submitted by Crick_user on Thu, 2017-11-30 07:09

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ctffind & ctftilt

Hey there,

I am using CTFFIND4.1.8 in Relion 2.1b1 on MotionCor2 corrected micrographs, Apix is 1.43 (73k Mag and detector pix size is 14um). I have noticed the --XMAG flag is not update and the --DStep is taking the Apix:

`which relion_run_ctffind_mpi` --i ./MotionCorr/job002/corrected_micrographs.star --o CtfFind/job038/ --CS 2.7 --HT 200 --AmpCnst 0.07 --XMAG 10000 --DStep 1.43 --Box 512 --ResMin 28 --ResMax 4 --dFMin 5000 --dFMax 35000 --FStep 500 --dAst 100 --use_noDW --ctffind_exe /home/[...]/ctffind-4.1.8/bin/ctffind --ctfWin 4090 --is_ctffind4

What am I missing?

thanks a lot!

Alexis Thu, 2017-11-30 11:01

You will still get the correct results. All that matters for ctffind is that dstep/xmag = psize. Setting xmag to 10000.0 is convenient, because then dstep (um) has the same value as psize (A).

xmag and dstep are separate parameters for historical reasons not relevant to ctffind itself.

Hope this helps,
Alexis