The blur is simply horrible

The blur is simply horrible and looks like a mistake, personally I'd suggest not using it as it serves no purpose, spoils the video because you can't see detail and is at odds with the other frame.

Key features are the physics. More light allows the camera to not need as much gain, reducing noise – and also increasing the depth of field – in the case of the guitar having the headstock and the right hand fingers infocus is difficult without light. You also need to consider contrast. when light levels are low, in your right hand picture there is an awful lot of black, and what whites are there are underexposed. Shadows of course give depth and visual interest, but too many spoil it. Lighting is frequently used as a blunt tool by many, which is a shame. I like sharp focus and everything in focus and rarely in my work do I want to work with the lens wide open and gain dialed in. even modest gain boost in my cameras produces too much noise.