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  1. doctordrone

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    Just noticed this with P4. In the DNG image, when I increase exposure or shadows in PS, all these (mostly magenta) pixels show up in the darkest shadow areas... any suggestions? I tried DJI DNG cleaner... no change.
     

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  2. sar104

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    What you are seeing is normal - you are trying to pull information from the shadows that is simply not there due to the limited dynamic range of the sensor. The pixels in question are nearly black, and when you try to lighten them the resulting color is mostly amplified noise.
     
    randykahl likes this.
  3. doctordrone

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    Ok, I'm following you. Is there an efficient way to clean that up? Or is it just spot healing each pixel?
     
  4. sar104

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    I don't know any way to fix that. The information is just not there in the original files. The RAW images may have a higher bit depth than 8 bit JPEGs, although I haven't seen the specs anywhere, but clearly not enough for that scene. If you want to see those kinds of shadow details then you need to increase the exposure, but that, of course, may result in blown highlights - the ubiquitous problem with high dynamic range scenes.
     
    #4 sar104, Mar 26, 2016
    Last edited: Mar 26, 2016
  5. thegoodtouch

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    I would clone stamp them out for existing pics and then focus on getting more data out of your pictures on the day for future shoots


    Sent from my iPhone using PhantomPilots mobile app
     
  6. sar104

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    It appears that the Exmor sensor in the P4 has a 12-bit dynamic range, but having compared some P4 RAW files opened in 16 bit space versus 8 bit space, I'm struggling to see much difference.
     
  7. WetDog

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    There is program wandering about on the DJI site called DJI DNG cleaner or something like that (can't look it at present). It will help with the hot pixel images. But sar104 is basically correct, you're down in the noise on a not very sophisticated (for 2016) digital camera. Maybe you could add a bit of fill flash ....
     
  8. sar104

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    Agreed. It's not at all bad for a point-and-shoot 1/2.3 sensor, but it's not going to do well at pulling detail from deep shadow, even with raw image data available. I haven't tried it, but it does have an HDR option - that would be another way to increase the dynamic range.
     
  9. WetDog

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    The HDR option is pretty worthless. You are better off using AEB (automatic exposure bracketing) and manually combining the images. But even that is pretty limited because it only steps the exposure in 0.3 EV unit increments (or maybe 0.7). You really want 1 or 2 units of change. Manually bracketing is a slow process and something that would only work for a very static image and stable drone.

    There are just limits to what you can do with the sensor.
     
  10. sar104

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    I hadn't tried AEB either but, having just tested it, it will do either 3 or 5 shots at a separation of 0.7, giving up to 2.5 stops of bracket. Better than nothing.