Photography Blog spotted a firm has patented a dSLR movie mode technology:
With the pervasiveness of Live View modes from DSLR makers, it is only a matter of time before similar technology brings a “movie mode” to DSLRs. While the ability to record video is a common feature among point & shoot cameras, technological challenges make the incorporation of a video recording more difficult in DSLRs. A recently published patent application by inventor Hiroshi Terada may change all of this. The patent addresses many of the technological hurdles that have prevented incorporation of a movie mode into DSLRs.
As we all know, DSLRs are designed for optimal performance in capturing still images - and DSLR manufacturers have truly raised the bar over the past couple of years. Accordingly, DSLRs are specialist tools that have been optimized to have a very narrow focus tolerance and an ever-increasing auto-focus speed. These features are not quite conducive to smooth video capture. Additionally, the field-of-view changes, albeit slightly, during auto-focus operation. Finally, fast and accurate hand-held auto-focus is dependent up accurate phase-difference AF evaluation, which requires a mirror to reflect the image to the AF sensor.
As you can see, getting live image to the image sensor and capturing smooth, in-focus video seems difficult to achieve without sacrificing some still image capture properties of DSLRs. These obstacles, among others, are what Mr. Terada attempts to overcome in his patent application.