F stop for landscapes w/ em-5

Just as many, in my opinion, worry too much about DOF and suffer too much diffraction softening.

For sure.  However, there are people, such as myself, who love shallow DOF as an end in and of itself, and consider the lower noise that comes with shallow DOF in low light to be a bonus.

That said, if I need more DOF in lower light, I stop down and strike a balance between noise and DOF.  Where that balance lies depends tremendously on the scene.