When i switch to camera view, i can see the rectangle area of cam fov. i can lock and edit cam pos/rot throgh that viewer. But i want a bigger workspace to work inside that fov, can i enlarge it ?
Ctrl+Alt+LMB drag. Ensure ‘Lock Camera to View’ is deselected in the properties panel. Or maximise the camera view with the Home key
Yes yes the problem … i didn’t uncheck the ‘lock cam to view’ , that’s why all the combination alt/ctr/shift were not working 
. Glad to have it works now. Thanx