Bye bye mirror

I had to have my mirror on the 5-D repaired and the whole shutter box had to be changed. It had just fallen off. Could it have simply been glued?

Sony Brings Pro-level Performance to Mainstream SLR Users with New High-Speed α57 Camera Featuring Translucent Mirror Technology

Advanced Feature Set Includes 12 fps Shooting, Full HD (60p) Video Capture, New Auto Portrait Framing and more

SAN DIEGO, March 12, 2012 -- A wider palette of creative options is now accessible to more shooters with the α57 camera, the newest addition to Sony’s popular line of A-mount cameras employing Translucent Mirror Technology.
The innovative Translucent Mirror design directs incoming light to the CMOS image sensor and the AF sensor at the same time, allowing full-time continuous AF during both still and video shooting.  Users can also frame, focus and preview shots in real-time on the high-resolution Tru-Finder™ electronic viewfinder, which offers a wide viewing angle and 100% field of view. This allows photographers to capture exactly what they see on the screen.
A natural successor to Sony’s acclaimed α55 camera, the α57 is positioned for a wide audience of DSLR users. It can shoot still images at up to 12 frames per second, capture full HD video at 60p, 60i or 24p frame rates and has a variety of creative modes including Auto Portrait Framing, a world’s first technology.
The  new thin mirror apparently seems to solve what were the difficulties of past designs