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DNG from I1 - Hot Pixels in Aperture

Discussion in 'Photos and Videos' started by acoll123, Jan 11, 2015.

  1. acoll123

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    I flew my I1 for the first time yesterday and just got around to downloading some stills. I took JPGs and DNGs and then imported them into Aperture. I noticed the DNG files have hot pixels while the JPGs do not (see attached samples).

    I also opened the DNG file in Photoshop Elements and the DNG file did NOT have the hot pixels so I am going to assume this is an Aperture problem.

    DNG files are not acceptable files for upload on this site so I can't share an original.

    Just an FYI for Aperture users. I may need to move to Photoshop sooner than I hoped . . . I have sent feedback to Apple via Aperture but it might help get support for the I1's camera if more than one of us did that . . .
     

    Attached Files:

    #1 acoll123, Jan 11, 2015
    Last edited: Jan 12, 2015
  2. damoncooper

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    Not sure I get the "hot pixels" reference?
     
  3. pgaucher

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    What does that mean exactly? Not familiar with Hot Pixels. How does it impact image quality and will it have practical day to day impact for non professional users?
     
  4. HunterSK

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    'Hot pixels' are bright pixels on the image sensor that are permanently 'stuck on'. Typically seen as either a white or colour-pixel (due to way the colour processing works). This is typically somewhat normal as the imaging sensor has millions of photo sites, and is made not visible by processing within the camera.

    However what acoll123 is talking about is a DNG file processing issue within Apple Aperture, and it doesn't appear to be visible using a different photo processing software.

    I must admit that I can't evidence of it from the uploaded samples as you need to show us a 1:1 pixel screenshot. Perhaps uploaded a 1:1 shot or upload the suspected DNG using a sharing service like Dropbox.
     
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  5. dronie

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    Pretty sure that's not going to happen.

    Apple has discontinued Aperture (even though mysteriously they still sell it) and there will be no further development on it, and I'm pretty sure that includes future profiles as well.

    Aperture will be replaced by their "Photos" app early 2015 - hopefully with the option to integrate a lot of 3rd party plugins for the semi-pro/pro user which would otherwise be pushed over to Lightroom (which isn't too shabby either) or other editors.
     
  6. HunterSK

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    Hi Guys,

    I'd like to point out a slight correction, on Mac systems the decoding of the RAW files is done by the OS, not Aperture. Aperture (and apps like Preview) understand RAW files because of OS X system updates that get regularly provided by Apple. Once these updates are applied, the RAW files become understood system wide.

    To help acoll123 along, I've obtained a RAW DNG file from another Inspire 1 owner who was kind enough to send me a still shot.

    Image (1):

    https://www.dropbox.com/s/ksodf4s2hk5uwro/Sample DJI_0015.DNG?dl=1 (24.3MB)

    On my Mac (OS X 10.10.1 Yosemite with all of the latest RAW updates from Apple as of today), I do not see any hot or dead pixels. The image looks fine. Could you please download the file and see if you are seeing the same thing as me?

    Here is a sample of the image magnified to about 4:1 seen on my system. This is what I see when I open up the RAW DNG and magnified.

    Update (16 Jan 2015): The file above has been definitely post-processed as it has the owner's details in the EXIF metadata. The author cannot remember whether the file has come out of the Inspire 1 directly, but the evidence points to the file being manipulated.
    [​IMG]

    As a comparison, I have the reverse problem on my Phantom 2 Vision+ where I actually see 'stuck/dead' pixels. This is only seen in Preview and Aperture, but not in Lightroom 5.6 which seems to indicate a problem with how the DNG file is processed on my system for the Vision+'s FC200 camera.

    This image (2) is what I see when I open up the RAW DNG and magnified to about 4:1.

    [​IMG]

    My workflow with the Phantom is to process it in Lightroom 5.6 (where I do not see the above dead pixels), process for lens correction and then I export a JPEG to Aperture (my preferred photo tool).

    From the sample provided (1), if the Inspire 1's FC350 camera really works perfectly on the Mac (without Lightroom), it would simply my workflow as I don't have to use another photo tool to do the lens correction.,
     
    #6 HunterSK, Jan 12, 2015
    Last edited: Jan 16, 2015
    dronie and lrwskyfilms like this.
  7. acoll123

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    Sorry - I meant to include a 100% crop - see the new attached files that clearly show the hot pixels.

    Andy
     

    Attached Files:

  8. acoll123

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    Here is a 300% crop - might show the pixels better. If you have an I1 and use Aperture, load a dang file and let me know if anyone else sees it. Hope fully it's just not me . . .
     

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  9. acoll123

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    My DNGs look exactly like this - but only from Aperture, not photoshop.
     
  10. HunterSK

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    Hi acoll123,

    I see what you mean, it looks very similar to my black pixel issue with the Vision+'s camera. I suspect it is a bug with how OS X currently reads the DNG file format produced by the Vision+ (FC200) and the Inspire 1's (FC350) camera system.

    As mentioned in my previous post, can you please load the following file into Aperture and see if you have the same issues. This file opens perfectly on my Mac. This file was supplied by another Inspire 1 owner.

    https://www.dropbox.com/s/ksodf4s2hk5uwro/Sample DJI_0015.DNG?dl=1

    Due to financial commitments I really shouldn't be splashing out on a AUD$4000 drone right now (luxury equipment), so I'm I1-less at the moment.
     
  11. acoll123

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    Thanks - I did open the file from your link in Aperture and it looks clean. Here is a link to my sample file - would you do the same for me and open in Aperture. This isn't a big deal for me since the files openly cleanly in photoshop, just an inconvenience. Like I said since Aperture is being discontinued, I assumed I would be moving to photoshop soon anyway unless Apple's replacement program is more advanced than I expect.

    https://www.sugarsync.com/pf/D8730850_98847488_6143599

    Thank you,

    Andy
     
  12. Morgon

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    Someone uploaded a file called 'DJI_008.DNG' (it's in my Downloads folder) and I see tons of hot pixels; but none in the (beautiful) shot that @HunterSK linked to. So I'm not sure it's completely OSX's fault.
     

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  13. acoll123

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    Did you try opening in another program like camera raw or photoshop? Just trying to isolate the source of the problem and right now it looks like an aperture OS X problem to me (I should say I hope it is - don't want to send my I1 camera back . . .)
     
  14. Morgon

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    That was just in Preview. I imagine Aperture/Camera Raw/Preview use the same rendering, given that they're native Apple programs. Photoshop would be the only one with its own renderer, but mine's not working at the moment, so I cannot compare.
    Curious if Photoshop tries to auto-correct hot pixels.
     
  15. HunterSK

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    Hi Andy,

    I downloaded your file and I confirm that I definitely see the black dots in both Preview and Aperture, matching your experience.

    Considering that:
    - artefacts occur in Aperture (and likely Preview as they both share the same renderer),
    - artefacts do not occur in Adobe Photoshop and Lightroom, and
    - the artefacts are very similar to the artefacts from my DJI Phantom 2 Vision+ camera (seen only in Aperture and Preview)

    Link to my RAW DNG from a Vision+

    https://www.dropbox.com/s/ep5naucndsyqv5a/Sample Phantom 2 Vision+ DJI00702.DNG?dl=1

    I suspect that it is a bug in the way that OS X currently renders these DNGs.

    I don't know why the Inspire 1 sample I uploaded don't show the same artefacts. Since they were taken from two different Inspire 1, it could be due to differences in software configuration or hardware (unlikely I hope).

    Update: I examined the metadata on the RAW DNG that I uploaded (Image (1) of the mountains). I believe that file has been post-processed as the meta information contains the owner's details. This is not done by the aircraft 's camera, so I think he post-processed and gave me the DNG (it is not the original RAW file). I'm going to email him and confirm this theory.

    Update (16 Jan 2015): The owner of the file says he can't remember whether the file has been post-processed, but the evidence shows that it has been. Therefore the DNG that I have posted has been modified and not directly from camera (not a RAW file).
     
    #15 HunterSK, Jan 12, 2015
    Last edited: Jan 16, 2015
  16. lrwskyfilms

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    Likewise I took 3 RAW pics and they have these "hot pixels".
     
  17. lrwskyfilms

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  18. acoll123

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  19. lrwskyfilms

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    I've just tried FastStone with their "clone and heal" and it seems of helped, but I'm only a beginner at photo editing, literally my first try at DNG RAW pics. Cheers Mark
     
  20. Morgon

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    I'm still looking for a bigger sample size to say it's OSX/Mac, rather than camera issues. Does anyone have a Windows workflow and is/isn't seeing the same artifacting?