I have a question about the CTF fits that I have been getting using patch CTF estimation in cryoSPARC version 2.13.2. As shown in the screenshot below I am getting what appear to be acceptable fits until around 7Å. However, at higher resolution it does not appear to fit the CTF despite the presence of signal. I have collected a similar sample (same protein and grid type with similar ice) on another microscope without CTF issues. The sample was collected on C-flat grids on a Titan Krios with a Falcon III detector. I have double checked the pixel size, accelerating voltage, and Cs values.
Any suggestions on avoiding this situation in the future and/or improving the CTF fit for this dataset would be greatly appreciated.
Many thanks in advance,