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Auto IRIS Issues with DJI Camera

Discussion in 'Phantom 2 Vision + Discussion' started by clipshot62, Oct 14, 2014.

  1. clipshot62

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    Here's a re=post that I slightly modified from an earlier post I found on the forum from july this yr.
    Thanks to nowwatch

    THIS IS A MAJOR PROBLEM - That seems like there should be a simple fix.
    Obviously only a problem for video footage - not stills.

    I'm not sure why this topic isn't discussed more, but the auto exposure function on the Vision 2+ camera renders most shots useless, especially when the camera is toward the sun within 90 degrees and contrast between the sky and and other white or dark objects pass though the scene. I've shot in many locations, attempting to record professional images, and continually experience poor results with instant auto exposure shifts or image pixelation. These shifts and flickers do not show up on the monitor, so we are not able to determine there's a problem on location unless we stop and watch every shot, which is just not possible when doing work on the move.

    I understand this is not considered a professional camera system, but can't we expect better camera control. Does anyone have the skills and know-how to hack the firmware and turn off this setting? We will pay for it. Will DJI offer this option soon???

    Seems like a simple firmware update to the camera could handle this?????? If this auto iris problem could be solved, the shots during a flt would be mostly useable vs only a few small sections of footage usable that I'm currently experiencing.

    Here are a few raw sample clips at 30fps that show the flicker and adjustment , and MOSTLY exposure shifts. The footage contains great sequences that are unusable...
    I have tested ISO in auto and setting it manually. WB AUTO and manual. Exposure 0 and -0.3. focus settings using all three. and as far as the auto iris issue - and till get the same result in all of these tests as far as shifting is concerned.

    Two questions - anybody know of a fix to turn off the auto iris on the DJI camera? and if not how about a plug in or other work around in FCP X?

    Footage Example 1
    http://www.youtube.com/watch?v=uI-qqAXW6ZI
    (Iris shifting)

    Footage Example 2
    http://www.youtube.com/watch?v=m-UZJi9vau0
    (whites blown out - iris shifting)
     
  2. Meta4

    Meta4 Moderator
    Staff Member

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    There is no auto iris on the DJI camera. It has a fixed aperture - no iris at all.
    The camera has limitations and you just have be aware of them and work with them.
    Any simple auto camera will have problems shooting high contrast pics or into the sun.
    The app gives you the ability to adjust the exposure +/-.
     
  3. AnselA

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    "Auto iris"? Do you mean fixed size aperture?
     
  4. Tripnman

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    Sounds to me as if the OP is having more of a problem with exposure metering. I've found that when using the "Average" setting the exposure changes dramatically throughout video shots as the light changes - the firmware is evaluating the entire scene and compensating for the variable light sources. Try using center or spot metering and adjusting your exposure compensation accordingly before running the flight.

    All that said, the camera on-board is not even a mid-grade consumer DSLR or handi-cam. Don't expect it to give you the same results and all is good. :)
     
  5. RedRyderMedia

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    I was thinking the same thing. OP is confused about how the DJI camera accomplishes exposure control. It is by adjusting the exposure time, not apperature. When I've seen the jumping problem described by OP as shifts, you might try a ND filter to reduce the amount of light hitting the sensor. That allows for longer exposure times and a smoother transition from one sceen to the next.
     
  6. clipshot62

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    OK thanks so much for the info. No iris at all on the cam - Ill try to adjust the exp settings again. Would be nice if one of the settings turned of the varible adjustments
     
  7. clipshot62

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    Agree that this is not a prof camera but overal when it is not shifting the quality is good enough. I now understand that it does not have an iris - thanks for the help
     
  8. clipshot62

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    Thanks vm for the info - will give that a try as well
     
  9. 4wd

    4wd

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    It's the metering you need look at, as above try the center spot rather than whole frame average, and set the exposure manually. -0.3 is often best unless it's getting dark
     
  10. clipshot62

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    Thanks again - will give that a try
     
  11. nhoover

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    I've had this problem too. Will try this solution. Thanks.
     
  12. timtown

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    You are facing a classical problem where the range of the high light values to the low light values appear to exceed the capacity of sensors. The problem appears worse when AWB and Auto ISO are enabled. I'm not a videographer by any means, but the problem can be handled readily with still shot images. In wet darkroom work days, one would always expose for the low values (for if you didn't there would be no information to work with) and then one would develop for the highs (effectively changing linearity of the exposure/density curve). Fortunately with RAW formats the true value from the sensors is being recorded. I would not use average meter exposure (because you may have a greater chance of dumping the low values in the frame images), but I would experiment with center meter exposure and a fixed ISO of 400. I would then process the RAW frames using a competent Adobe editor that properly handles the camera's RAW data format (which is unknown to me).

    Hopefully, the low values will be captured. Then, you can adjust the end points depending on your image interest. You may choose to blow out the high values and preserve the low values with important image content. With adobe bridge, you can pull down those high values (which probably contain information of little interest). What you don't want is an exposure that dumps the low values because the foreground has a featureless white roof top in the foreground, or the bright sun reflections elsewhere.

    The camera has its limitations, but fortunately, it will record in RAW which gives you a fighting chance.

    If this didn't work, using simple broad brush editing, one would have to resort to more specialized software that can create make selections within the frames based on one density or another. You would then make adjustments to those selected areas.

    I know a couple of professional videographers that will make a recording, play it back using a computer Then, they will re-record and some other time of the day or chose different camera positioning due to this limitation.Stephen Wheatcraft will first record with his PV2+, analyze, then use his s1000 with a canon 5d M3 to make the one he wants to keep.

    -Tim
     
  13. clipshot62

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    Thank you so much for this great information. I'm not having problems with shooting stills as I am shooting in RAW/jpg and the shots are fine.
    The issue is only with the video footage that does exactly as you have described. Im going to try some of these other tests with the settings that are available on the camera and see if it can at least - be improved.
     
  14. AsiaFlyer

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    My 2nd V+ has similar problems, I only use fixed settings, ISO 100, Sunny white Balance and here are the terrible results: http://www.youtube.com/watch?v=7YSFdCrDcaI

    Also have same flickering problems on a few other videos I shot.

    My 1st V+ shot brilliant video, never had any flickering on 100+ flights

    It's in with my dealer at the moment for testing but he has not had the flickering problem on his test flights so far but it's been cloudy on every test flight he has done at the moment.