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Adaptive camera flash

lowres transparent lcd screen in front of flash
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If the camera senses low light, and selects to use the flash, sometimes, some objects which are nearby or are already very bright, come too bright. If the camera is able to adjust the brightness of the flash, and it sees a bright object, it might end up making the flash too low for the whole scene.

To solve all these problems, I envision a transparent lcd in front of the camera that lets the camera choose how much light should be projected at which part of the scene. With most cameras today being digital, this is not a problem. Cameras today have amazing computing power, so I dont see a problem with that either.

kamathln, Sep 19 2010

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       You’re describing a kind of “dodging and shading” apparatus in hardware, at the optical level.
Ian Tindale, Sep 19 2010
  

       Sounds OK to me, as long as the flash can be "focussed" to produce a respectable shadow of the mask.   

       Might it be simpler, though, for the camera to take two images (with strong and weak flash), and combine the two to create a uniformly-reasonable apparent exposure?
MaxwellBuchanan, Sep 19 2010
  

       A focussed flash through a LCD screen sounds like a video projector to me. It could be quite effective, though the inevtable mis-aligned edges due to parallax (Yes I had to look up the speling), focus and processing errors will make the picture look a bit odd.   

       Better to have a much larger flash mounted on a boom a long way behind the photographer?
pocmloc, Sep 19 2010
  

       Perhaps you could use a semi-transparent CCD (charged couple device) similar to that used to record the image, that acts as a filter?   

       You could add a function to feather the edges of those near objects you seek to mask, to prevent hard edges showing up as double lines in the finished photograph.
infidel, Sep 19 2010
  

       [IanTindale], right! But post processing usually means loss of original data. Letting the cam selecting the right amount of light for all areas will mean maximizing the amount of data(eveident in the histogram) for different areas.   

       [MaxwellBuchanan], that works for something standing still. [pocmloc], That wouldn't be feasible for every setup. My idea can be implemented even in point and shoots and can be used needing to setup anything previously.   

       [infidel], yeah of course, this is somehting that will need to be experimented and refined further. My idea of posting this idea is to shed light in an area which has not been thought of before (pun semi-intended).
kamathln, Sep 20 2010
  

       How about camera firmware to use different exposure times for different groups of pixels? It might not be possible on some CCD architectures, but they can certainly be designed for it. The only difficulty comes in deciding what the exposure times should be. Perhaps a test image could be captured first, then automatically adjusted for the main image.
Aq_Bi, Sep 20 2010
  

       The exposure time of the shutter (or even, the “shutter”) is vastly greater than the illumination period of the flash duration.
Ian Tindale, Sep 20 2010
  

       True, but it would work for images which don't use a flash. Or some areas can be exposed without the flash at all. Given a bit more advancement in technology, and there would be no reason it couldn't close the shutter on some pixels part way through the flash. Even a short 1 µs flash only needs a 1 MHz clock cycle.
Aq_Bi, Sep 20 2010
  
      
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