Texture paint - texture scaling

Hi

I am trying to use texture paint feature in blender. It seems that the scaling of the painted texture depends on how closely I am zooming the 3D object while painting. Furthermore, if I change the zoom of the view the scale of the painted texture also changes.

I would like the scaling of the painted texture to remain constant and independent of what the view zoom is. Also I would like to manually choose what is the scaling of the painted texture. How to do this in blender?

Thanks