The above sample clip demonstrates the HDRx voodoo that RED is working in its new EPIC camera.  The shot from dimly lit tunnel to a sunny afternoon maintains the aperture and other exposure settings during the transition.  No one is pulling aperture via a remote during the transition.

Using the new HDRx feature in the EPIC, the camera makes the previously-impossible now possible.  The HDRx functionality works by recording two exposures and blending them together, which allows the camera to hold the highlight details in the clouds after emerging from the tunnel in the above video.  The exposures are captured simultaneously, with the underexposed frame recorded at a fraction of the shutter speed of the “normal” frame.  Not even film has this kind of latitude.

[fxguide via Prolost]