Infinity CTF fit during CTF estimation

solved

#1

Hi,
I imported my movies and made motion correction followed by CTF estimation. Approximately one third of my data have a CTF Fit “value”: Infinity. Anyone can explain me what does this mean? The majority of these micrographs look nice and the power spectra look nice too.
Nevertheless I would like to get read of those micrographs but in the individual mode it would take forever (I couldn’t find any way to select more then one micrograph at a time in this mode) and the overview mode doesn’t work, the CTF Fit resolution threshold shows the values 0 to 0. When I try to set the values to the lowest and highest values to exclude the micrographs with infinity CTF fit resolution, cryoSPARC crashes.

Thanks in advance!

Maria


#2

Hi @Maria,

The issues with exposure curation when there are Infinity values were fixed in v2.3.0 - in this version you are able to select using the overview mode, even if there are Infinity values present. If you set any thresholds other than the default thresholds, Infinity values will be removed from the selection. Then you can accept the selection, thereby separating the Infinity value micrographs.
The Infinity values themselves come from CTFFIND being unable to compute the fit value. Changing the parameters of CTFFIND (for the specific micrographs that get infinity values) may be able to help with this.