What is the difference between Set Render Border and Set Render Border Camera Only? In version 2.79b, and when in the 3D Editor area, two shortcuts call view3d.render_border with a parameter camera_only:


ctrlB sets the parameter to False
shiftB sets the parameter to True


The later shortcut is actually assigned to two functions in the user preferences:

  

so, for the purpose of this question, I've disabled temporarily "Zoom to Border", to allow "Set Render Border" to be called. The configuration is:

  

My understanding:


Those two Set Render Border shortcuts allow to define a rectangle in the one of the 3D view (not necessarily Camera view).
The result is visible in the rendered image (F12) and/or in the 3D view but only when in shading mode "rendered"


In practical, when using any of them:


In the 3D view, only the rectangle is shaded in "rendered" mode, the rest is shaded in "solid" mode.
In the rendered output, only the rectangle is rendered, the rest is empty.


  

My question: What is the difference between the two shortcuts? Or is shiftB (camera_only = True) an unintentional leftover?
SHIFT + B lets you select a portion that you wish to see in the final render image or in the camera view.



CTRL + B lets you select  a portion you wish to see in the render view mode. to then delete the border is CTLR + ALT + B



while CTLR + B works also in camera mode, SHIFT + B if is not in the camera view mode acts as a zoom tool.



CTLR + B does not affect the camera view or the final render. unless you are already in camera view