While the advanced processing, glass and sensors of DSLRs
has made them a likely candidate for video capture for some time now, a few technical obstacles have stood in the way. All that could be changing, though, with this DSLR "Movie Mode" patent from Japanese inventor Hiroshi Terada uncovered by Photography Bay. The wide-ranging patent addresses trouble spots such as AF focus speed and tolerance, and the auto-cropping DSLRs perform during AF adjustments, but most interesting is the mirror. The patent suggests a mirror that lets through 70% of light, while reflecting the other 30%. Reflected light can be used for continuous AF, while transmitted light is captured on the camera's primary sensor. This mirror configuration also allows live view
while shooting stills. There's no telling when we'll start seeing this in cameras, or if any major manufacturers have even licensed it yet -- or have developed similar systems -- but it does seem clear that DSLR movie shooting is fairly inevitable.
[Via Photography Bay