I was watching the Sony ad video clip for the NEX-VG10 HD cam with the interchangeable lens ability and the "4 capsule mic" (sold out in Canada). In the video the focus at one point switches from the foreground subject to one in the background seamlessly. How do cams do that? Do most HD cams have a "foreground AF/background AF" button allowing you to switch back and forth?
Novice ?...how do HD cams control DOF?
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Probably done like any other camera, by manually adjusting the focus...
On my Panasonic HDC TM700, you simply put it in "manual focus mode" and turn the front ring.
It could also be done in "auto focus mode" with "focus zone selection" (if the camcorder is equipped with such a system like the TM700) but the result would be a very quick change from one subject to the other instead of a slow, smooth one.
In any case you need a camera with manual control of shutter speed and aperture, (or better yet a ND adjustable filter) in order to get a shallow DOF to begin with. And camcorders with small sensors will have less of a wide range as large sensors ones.
Probably done like any other camera, by manually adjusting the focus...
On my Panasonic HDC TM700, you simply put it in "manual focus mode" and turn the front ring.
It could also be done in "auto focus mode" with "focus zone selection" (if the camcorder is equipped with such a system like the TM700) but the result would be a very quick change from one subject to the other instead of a slow, smooth one.
In any case you need a camera with manual control of shutter speed and aperture, (or better yet a ND adjustable filter) in order to get a shallow DOF to begin with. And camcorders with small sensors will have less of a wide range as large sensors ones.
Some cams have manual focus, which is the only reliable way to pull that off. And that's focus only. DOF is more a function of sensor size and how much zoom one is using. Zoom plus your orientation to the subject is about the only way to control DOF on most consumer camcorders. Since consumer camcorders tends towards very deep DOF (everything in focus). Unless you use zoom. Beyond that you might be able to lock focus on something roughly equal distant and then unlock to let auto focus take over. But otherwise no manual controls while recording on some models.
Ok thanks guys for the explanations. I am into photography (using a Nikon D300 DSLR now). Just wondered if there wasn't a feature. Apparently there is on some cams (e.g. auto zone). Don't know why I never thought you could also accomplish this by just focusing and defocusing.
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Later guys.
Later guys.
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