How bright is the solar corona compared to the full moon?

It varies tremendously, depending on how close to the solar disk. In terms of camera exposure, right close to the solar disk it is about as bright as the full moon. The outer corona, beyond 4 or 5 solar radii away, is about 8- 10 stops dimmer. read more

The corona varies dramatically in brightness from the inner portion near the sun to the outer portion a few solar radii away. The innermost portion is the brightest; at ISO 100 and f5.6, an exposure of ~1/125 second will capture it. So it's roughly the same brightness as the full moon. read more