Dear all,
On the "Searches" tab of CTF job-type in Relion3, there are some parameters to set. These parameters and their default values in the Relion30 tutorial are:
• FFT box size (pix): 512
• Minimum resolution (A): 30
• Maximum resolution (A): 7.1
• Minimum defocus cvalue (A): 5000
• Maximum defocus cvalue (A): 50000
• Defocus step size (A): 500
• Amount of astigmatism (A): 100
I wonder what the "FFT box size" mean? Is it related to the particle diameter? How to set the other paramter? Is it OK to use the default?
For the Manual particle picking job type, in the "Display", I don't understand the setting of the following parameters:
• Sigma contrast: 3
• White value: 0
• Black value: 0
About the , the tutorial states that "black will be 3 standard deviation below the mean and white will be 3 standard deviations above the mean". I wonder why the "white value" and the "black value" are both set to 0. If the "mean" value of the grey-scale is 0, they why the the "white value" and the "black value" are set to 3 and -3 respectively?
Best regards