Update About

About.md

@@ -18,14 +18,14 @@ where $`\lambda`$ is electron wavelength, $`CL_{eff}`$ the effective detector ca
 Electron probe grows in size with induced defocus accordingly to the probe semi-angle. For proper reconstruction, the probe has to fit into _probe window_ with some safety margins (recommended is to use half of the window). Maximum defocus is so given by
 
 ```math
-\Delta f_{max} = \frac{w_{full}/4}{\tan \alpha_{corr}} [to test]
+\Delta f_{max} = \frac{w_{full}/4}{\tan \alpha_{corr}}
 ```
 
-where $`w_{semi}`$ is probe semi-window, $`r_{0}`$ the beam radius with 0 defocus and $`\alpha_{corr}`$ the real probe semi-angle.
+where $`w_{full}`$ is probe window and $`\alpha_{corr}`$ the real probe semi-angle.
 
 ##### Pixel size in the reconstructed image
 
-is given by
+Pixel size in reconstructed image made by iterative methods is not given by real space electron probe sampling density, but by maximal angular cover of the detector. It can be calculated by
 
 ```math
 pix_{ptycho} = \frac{lambda CL_{eff}}{N_{eff}d_{eff}} [reference]