I have a Sony a6500 (4k) and a Sony a7s (1080). I will be shooting a feature film with the a6500 as the main cam, and A7s as the B-cam. I am very adamant about using two cameras - mostly for dialogue scenes to have natural flow (I realize this will require another mic or at least a talented boom guy). I wanted to see if anybody has any tricks or tips on how to do this properly without noticing the difference in resolution/detail. My kneejerk idea is to keep the A7s very tight on the subject with very shallow DOF to emphasize the foreground sharpness. The a6500 seems like it would be better for the master shot or wide shots, as it can pick up greater detail from further away. This may just be totally assumption, but I'd like to know your thoughts. Has anyone ventured into the realm of 4k/1080 mixing before? If so, can you help?