Shadow view distance?

[anonymous_user_7cacdf5b]

I have a level only using a few BSPs with different materials and a directional light.

However, shadows seem to be removed, and my tunnel becomes perfectly lit, when I move the camera/player away from the tunnel. How do I fix this?

See attached image.

[anonymous_user_7cacdf5b]

Built lightning with production quality removed the shadow distance problem.