Because uncompressed RAW means huge files that take up a lot of disk space, take a lot of time to transfer, and require considerable computer power to deal with. But with Log encoding you get the vast majority of flexibility in what the sensor can capture but recorded in a data scale that is reasonable enough to everyone to work with. Clients won’t complain about the data load and the work can happen quickly and effectively.
Uncompressed RAW has been available for well over a decade on major camera systems and devices I’ve been directly involved with. The vast majority of people who owned these or considered owning them hated the workflow and often did workarounds to avoid it. When reasonably compressed Log recording became available to these same devices their popularity skyrocketed. It has happened numerous times.
DPs who don’t have to care about workflow want uncompressed RAW. DPs shooting for the highest level productions want uncompressed RAW. I understand that. But they comprise an infinitesimal percentage of actual users. Most people want the advantages of capturing all that dynamic range while not having the burden of uncompressed RAW workflow. For a petite and inexpensive camera such as the Sigma FP I would argue that the vast majority of people considering its use, compressed Log video is far more attractive than uncompressed RAW.
[Mitch Gross] I would expect that Log encoding is more useful to a vast number of CMLers and DPs in general than Uncompressed RAW recording.