The Lumix S1 & S1R were both introduced early 2019. They were well accepted by the market. The factors holding the wider adaption of these cameras were size, weight and autofocus speed.
The Lumix S5 overcomes these factors ....
High Quality Images, Exceptional Quality Video, In A Compact Body
A hybrid (video/still) feature packed full frame mirrorless camera with the flagship features of the Lumix S series in a small light camera which is affordable.Uncompromising Image Quality
Vast Focus Performance Improvements Compared To Earlier S Series Cameras
These enhancement will be incorporated in a firmware update to the S1, S1R and S1H later in the year
Other features :Panasonic is offering the choice of a Sigma 45mm Lens or a Panasonic XLR adaptor if you pre-order a Lumix S5. For further information click here.