DSLRs Shoot Video With New Patent

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The one feature point-and-shoots still have over DSLRs is the ability to shoot video clips. DSLRs are optimized in the other direction—the mirror setup, specialized auto-focus systems, etc. Hiroshi Terada's patent for a movie mode on DSLRs has one big innovation—a semi-transparent mirror—and then pulls a PS2-on-PS3 emulation trick, cramming in the components necessary to shoot solid video alongside the DSLR's regular components.

In order to shoot at 30FPS, Photography Bay notes that a DSLR's mirror would have jump up and down at least three times faster than Canon's EOS-1D Mark III. Terada's semi-transparent mirror doesn't move, but lets 70 percent of the light through to the image sensor, enough for video. The reflected 30 percent takes care of your continuous phase-detection autofocus.


The patent actually uses two different autofocus systems—one for still image shooting, and then another for clips, which has a wider AF threshold (DSLRs tend to have a very narrow one) and a slower, smoother AF speed (vs. the light speed you want for still images). A cropping function would take care of field of view changes that happen during AF shifts.

After Live View, this was the only place left to go—the question is when we'll see these first Zapruder-capable DSLRs, though the next generation doesn't sound like an unreasonable time frame. [USPTO via Photography]