I'm messing around with sharpening in Camera Raw, is it true that when shooting in Jpeg the digital camera applies sharpening automatically ? What's happening when shooting with an iphone ? It's true as well ?
Every camera model is a little different, but there is usually in-camera sharpening for JPGs, yes, although some cameras have a way to adjust how much. For a tiny camera like that in an iPhone, I’m sure there are all sorts of lens-geometry corrections, noise-reduction, and sharpening applied before the JPG is created.