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Photo DNG issue

Discussion in 'Pro/Adv Discussion' started by adrian8891, Mar 18, 2016.

  1. adrian8891

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    Hello Phantom users.

    I have some problems with my DNG photos.

    First time I made this raw files with HDR function.
    What I get after enter import mode in Lightroom:
    import.jpg

    and this is what I get when double click on photo to preview it:


    afterimport.jpg

    Where might be problem?
     
  2. With The Birds

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    Problem might be significant underexposure of source images. A lot of noise, particularily in the dark areas. This is expected performance for this camera. Use manual mode to keep the iso as low as you can for exposures up to ariund 3 seconds. Not all shots will be usable so take plenty. Use the standard clear filter, you want as many photons as you can get finding their way into the sensor (nd filters work against you here). Also looking at the overall colour cast here you may consider manual colour temp (custom) setting and shoot with the histogram active to set your exposure. You are often better to set the brightest elememts of the scene right on the limit to get lowest noise in the dark areas.
     
  3. adrian8891

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    Ive done a lot of photos with my DSLR at manual mode. Same here, I set to manual mode and reduced iso to 200. Problem is with photo itself. Seems that black areas are filled with this blue something and it should be BLACK just as on thumbnail. Tried to put card onto android device and open with android Lightroom. Same...thumbnails are good, but after opening photos all of them looks like this.
     
  4. With The Birds

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    The blue specs are sensor noise. The pixel density is high (small sensor) so the individual photosites on the chip are a lot smaller than on your DSLR. Less photons available to be captured means the self generated noise in the sensor and other electronics has a significant effect on the signal to noise ratio. It is always most apparent in the darkest areas (you would have seen this in your DSLR experience to a lesser extent). Poor images always look better in thumbnails, the same as larger prints reveal technical limitations of your equipment.

    I maintain that the images would be improved by increasing the exposure.
     
  5. adrian8891

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    I know what do You mean, but please understand that on thumbnail I cannot see this blue things. Whats more, when I open these photos in DJI GO app in preview mode (full screen photos) it appears OK!. Take a look that photos on thumbnail and bigger version are almost totally diffirent so there is no way that "poor images always look better on thumbnails". There is definietly problem with Windows or Android, because (I repeat) in DJI GO app in preview mode it look very great and as it should look like.
     
  6. Meta4

    Meta4 Moderator
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    If you were using the built-in HDR feature in the Phantom rather than bracketing using the AEB feature to create your own HDR image you will usually get poor results.
    HDR isn't much good anyway for night city photos which work well without it.
    The Phantom's camera is quite capable of good night photos without messing around with Raw and HDR.
    Here's a good example of what can be achieved just shooting jpg anda no HDR
    [​IMG]
     
    NRJ likes this.
  7. With The Birds

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    You wont see a pimple or small blemish on a models face on a thumbnail either. Think about it, the thumbnail is generated with significantly less pixels than the native resolution of the image (and full screen view for that matter) so it must interpolate pixels. The noise will be averaged and significantly less apparent if visible at all. Poor images always look better in thumbnail veiw.

    The dng images contain raw image data from the sensor plus an embedded image for thumbnail display, this is likely what you see in the go app.

    I have found that some images that appear acceptable in the go app have significant issues.
     
  8. Air Ontario

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    Nice meta4, is that Perth?

    I thought LR imported them as they are, then you can select to arrange them UE to O Exposed. Those are all very dark.
     
  9. adrian8891

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    I also thought that LR import photos as they are. Now I just dont know is it issue of phantom, DJI GO, DNG codec or anything else.

    Why do You think that HDR function in DJI go is bad? I shoot RAW only and I dont want to shoot JPG.
     
  10. Meta4

    Meta4 Moderator
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    Well try just shooting ordinary shots rather than the DJI version of HDR and compare.
    HDR can be very good for some subjects and lighting situations or it can be a mess.
    The DJI implementation of HDR is a lot less useful than bracketing with the AEB function and doing the blending yourself.
    But for night cityscapes where the photo is all lights rather than lit subjects and shadows you probably don't need HDR anyway.
     
  11. adrian8891

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    Maybe Youre right. Problem also appeared when I tried to do HDR photo of myself in indoor at daytime. Very less of photo had this blue dots.
    I know that making blending myself is better, but try now to tell some person to stand still for 30 secound without any move, because I have to manually change exposure etc. ;)
     
  12. 4wd

    4wd

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  13. adrian8891

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    I have already tried - changed nothing.
     
  14. With The Birds

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    Acquiring the images with manual bracketing is really your only option atm for good reaults. I say that because the AEB function cant be adjusted, i think it is fixed at 1/3 stop from memory and most shoot at lest 1 1/2 stops over and under 0EV (3 stop bracket) to get the benefit of HDR or exposure fusion blending.

    The DJI DNG ckeaner works quite well on hot pixels hiwever not suorised it didnt do much with the images you posted.

    The phantom canera is not as forgiving as current DSLR caneras. You dont have anywhere near the lattitude and low light work is tricky. META's example proves yiu can get good results. I suspect the sample posted is 6 or 8 stitched frames so a lot more pixels than a single frame and issues will be less apparent when veiwed at reasonable sizes. Its a beautiful shot and shows what can be done.

    Looking at yiur sample image again aside from being underexposed it looks like you have blur also. what where your exposure settings?
     
  15. adrian8891

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    Exposure was not able to set. Phantom do this automatically on HDR photos. Blur might be caused by long shutter speed. When I get home will host raw photos so You can look for meta data then. Good thing is only that it wasnt "only chance" for this photos ;)

    Today maybe I will experiment with change to jpg HDR or try to make few raw photos without HDR
     
  16. Meta4

    Meta4 Moderator
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    AEB is in 0.7 stop increments. So you only cover a range of 3 stops (+1.5 and -1.5)
    It's hard to understand why DJI have left this .. it would seem to be simple to make it 1 stop which would be more useful.
     
  17. adrian8891

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  18. adrian8891

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    Ok.

    I may upgrade now thread.
    Today I have flew once and tried HDR in RAW + JPG. RAW was equal to those posted last time (terrible photos), and JPG came a bit "flat" but without those blue dots (it was HDR so it should be beautiful, not flat).

    Last time I tried 1 single photo on manual settings and in my opinion it came better than all other HDRs.
    013, 020 - HDR
    DJI_0013.JPG DJI_0020.JPG
    022 - non HDR
    DJI_0022.JPG