Originally posted by Yohan Pamudji That would be interesting. An optical/electronic hybrid viewfinder. I wouldn't care so much about this for live view, and I have no idea about the technical feasibility of such a beast, but this would be GREAT for video. All of these look-at-the-back-LCD-for-video implementations are junk. Being able to look through a viewfinder while taking video would be terrific.
I was trying to think about what trick Pentax has up it's sleeve for the viewfinder as that's what some are hinting at. I was thinking of a hybrid optical/electronic hybrid viewfinder, sort of like a HUD for a plane. They could project a histogram and other useful information on the OVF when using the OVF but it could also project the view from the sensor when the mirror is up.
In addition to video as previously mentioned, this would be helpful with mirror lockup, bulb exposures, and continuous shooting. In fact I'd find it extremely helpful to not have the viewfinder blackout when not in continuous shooting as it's easier to monitor people's facial expressions and movements to prepare for the next shot when the viewfinder doesn't blackout (think rangefinders).
Another thing that could be done is simulating the exposure of the final image and depth of field similar to what can be done in LiveView, but done inside the viewfinder where there is less problems with glare, contrast, etc.
Thinking about it, a hybrid viewfinder would be a pretty big innovation for SLR cameras.