Yes, it features a dust and moisture-resistant design with rubber gaskets at all seams and a rubber ring sealing the lens mount for professional use in harsh conditions.
Yes, it is a native E-mount lens perfectly compatible with the Sony A7 IV and all other Sony mirrorless E-mount cameras.
The lens uses a standard 82mm front filter thread, compatible with most professional circular polarizers and ND filters.
The GM II is approximately 20% lighter, smaller in volume, features significantly faster autofocus with four XD motors, and includes a dedicated aperture ring.