The internal selfie camera, which will reside under the panel will sport a 16MP Sony IMX471 sensor with 1.0 µm pixels and will be 1/3.09″ in size. The front panel (when folded) selfie webcam will use the very same 10MP IMX374 sensor as the Fold2.
We have actually heard Samsungs upcoming Galaxy Z Fold3 wont bring a major upgrade in the electronic camera department, now we get some more specific details on its hardware.
The leakage recommends that the back will again include a trio of 12MP shooters, but unlike the Fold2s setup the ultrawide system will use PDAF (Phase detection autofocus).
Source