Video Mode:
4K30p (3840x2160p29.97) applies a 122.5% crop to the APS-C sensor compared to 4K24p.
20mm f/2.8 will look like 30mm f/4.2 @4K24p
20mm f/2.8 will look like about 35mm f/4.5 @4K30p
Sony ClearImage allows to zoom about 200% from Full Frame, meaning:
20mm f/2.8 will look like 40mm f/5.6