Normally, muscles change its shape by contracting or relaxing, determining where light rays passing through the eye converge.

Instead the rays converge somewhat behind the retina.

In the nearsighted eye the rays converge in front of the retina.

Distant rays, due to their parallel nature, converge to a point on the retina.

At the point where the rays converge, you get a real image of the candle.

This can be corrected with convex lenses which cause light rays to converge prior to hitting the retina.

Whichever way you held them, they would have been quite unable to make the rays of the sun converge.

Because the rays never really converge, one cannot project a virtual image.

Intuitively, if the light rays are converging, this means that the light is moving backwards inside of the ball.

If all the rays around the entire surface are converging, we say that there is a trapped null surface.