If the 'Full Frame' body was using a 24-70/2.8 lens and the 'APS-C' body was using a 16-50/2.8 lens, they would both be capable of almost identical images, but with an aperture of f/2.8 and a subject distance of 7 feet, the 'Full Frame' body would have a DoF of 0.5 feet and the 'APS-C' body would have a DoF of 0.66 feet, about what the 'Full Frame' ...
A Double Pole Double Throw (DPDT) switch is a switch that has 2 inputs and 4 outputs; each input has 2 corresponding outputs that it can connect to. Each of the terminals of a double pole double switch can either be in 1 of 2 positions. This makes the the double pole double switch a very versatile switch. With 2 inputs, it can connect to 4 different outputs or reroute a circuit into 4 different modes of operation. A Double Pole Single Switch is actually two single pole double (SPDT) switches.
A soft-loading transfer switch (SLTS) makes use of a CTTS, and is commonly used to synchronize and operate onsite generation in parallel with utility power, and to transfer loads between the two sources while minimizing voltage or frequency transients.