What Full-Frame means in practice
A full-frame sensor at 24.3MP gives the shallowest depth of field of the three formats at any given framing and aperture, and the most sensor area to gather light with. That is the physical reason full-frame bodies tend to be the larger and heavier option: the lenses that cover the format have to be bigger too.
Video, stabilisation and weather sealing
4K tops out at 30p, which covers standard delivery but leaves no room for slowing footage down.
In-body stabilisation steadies any lens mounted on it, including primes with no stabilisation of their own. The body is weather-sealed.
