https://opencamera.sourceforge.io/help.html
“Use Storage Access Framework - If selected, Open Camera will instead use the Android Storage Access Framework. This has some advantages, such as using the standard Android file picker, and being the only way to save to SD cards on Android 5+. Furthermore on Android 10+, it is the only way to save outside of the DCIM/ folder. (Requires Android 5.0 or higher.)”