Moste lenses exhibit some distortion, barrel or pincushion. Some modern cameras, like yours, automatically correct for this in-camera when creating the JPEG image.

In turn, camera producers skimp on their lens's optics to produce a smaller image circle, since the corners won't be seen on the JPEG anyway. The RAW image, though, is uncorrected. (Try to take a picture of a brick wall or anything with straight lines)

If you compensate for the distortion in the developer software on your computer, the dark corners will get cropped, too.

Most lenses exhibit some distortion, barrel or pincushion. Some modern cameras, like yours, automatically correct for this in-camera when creating the JPEG image.

In turn, camera producers skimp on their lens's optics to produce a smaller image circle, since the corners won't be seen on the JPEG anyway. The RAW image, though, is uncorrected. (Try to take a picture of a brick wall or anything with straight lines)

If you compensate for the distortion in the developer software on your computer, the dark corners will get cropped, too.