Thread: Helium Sensor Smearing

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  1. #11  
    Not to mention that's at 4000 ISO? Mine is between 800-1600... so it's not like I've been overexposing like mad.
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  2. #12  
    Quote Originally Posted by David J. Buchanan View Post
    Not to mention that's at 4000 ISO? Mine is between 800-1600... so it's not like I've been overexposing like mad.
    Remember that Helium is now one stop brighter than Dragon. So that 4000 ISO is like 2000 ISO on Helium.

    For what it's worth:

    ISO 800 v2/1600 v1, IPP2 med/med, standard OLPF


    ISO 6400 v2/12,800 v1, IPP2 med/med, standard OLPF


    I personally am not pushing the Helium sensor any further than 800-1280 for noise reasons anyway. The 6400 ISO image above is already unusable, so it's not like the smearing is ruining an otherwise great shot. So I guess if you shoot in a way to minimize noise you'll also minimize the smearing effects.

    Edit: An interesting thing to note in my testing: I had to use my flashlight's dimmest setting to provoke the smearing. If it was on any of the brighter modes, the lens would flare, filling in the nearby shadows and eliminate the effect.
    Last edited by Aaron Lochert; 12-04-2017 at 07:37 PM.
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  3. #13  
    Quote Originally Posted by Aaron Lochert View Post
    Remember that Helium is now one stop brighter than Dragon. So that 4000 ISO is like 2000 ISO on Helium.

    For what it's worth:

    ISO 800 v2/1600 v1, IPP2 med/med, standard OLPF


    ISO 6400 v2/12,800 v1, IPP2 med/med, standard OLPF


    I personally am not pushing the Helium sensor any further than 800-1280 for noise reasons anyway. The 6400 ISO image above is already unusable, so it's not like the smearing is ruining an otherwise great shot. So I guess if you shoot in a way to minimize noise you'll also minimize the smearing effects.

    Edit: An interesting thing to note in my testing: I had to use my flashlight's dimmest setting to provoke the smearing. If it was on any of the brighter modes, the lens would flare, filling in the nearby shadows and eliminate the effect.
    Aaron, these images are with direct light, which yes, will look this terrible and in some/most of my cases would show this bad. However, let's assume I can avoid this (but not really)... It still happens even non-direct light.

    https://drive.google.com/open?id=1_Q...GgxcDkbjGM65ri

    https://drive.google.com/open?id=10V...jkMuHwLq9TKUH_

    This is what bothers me.

    Doesn't matter if I drop the ISO to 640, still there. Yes, it can be graded down, but what if I didn't want to crush my blacks. Well, now I have to.
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  4. #14  
    Hmmmm, that is interesting. The rear dash of the car isn't even clipped but it still bleeds into her hair and his headrest.
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  5. #15  
    Quote Originally Posted by Aaron Lochert View Post
    Hmmmm, that is interesting. The rear dash of the car isn't even clipped but it still bleeds into her hair and his headrest.
    Yes! Exactly! It's terrible man... Some have told me just send my camera in... I dunno maybe I should. But I got stuff coming up and I can't be rolling without the Weapon since I've already been filming on it.
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  6. #16  
    Moderator Phil Holland's Avatar
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    I've had a look at the file.

    So here's the info on sensor smear. It's different and improved on Helium compared to Dragon in general.

    However, there's a few things to be aware of. In David's example he is using the newer ISO calibration. So in the example R3D it's rated at ISO 1600 (previously 3200 ISO), though the shot looks to be about right in the ISO 400-640 range when grading to the skin tones.

    As the shot is certainly exposed closer to the noise floor it would be "safer" to expose at a lower ISO in this given circumstance. I have yet to see the smear show up in this particular scenario, but the new calibration is pretty new and people will need to adapt to it.

    It is something that can be graded out in this case, but I agree it's not ideal. But the true answer here is exposing for a lower ISO given the contrast ratios and light intensities.
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  7. #17  
    Yeah, even with a kind of contrasty grade you can still make out the smearing.

    [IMG]A025_C011_0902M4.0000789F by rand thompson, on Flickr[/IMG]
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  8. #18  
    I mean your black levels are still quite lifted. I would probably start with something more like this as a base grade.

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  9. #19  
    Aaron,

    Yeah the blacks where lifted because I just threw on a little contrast to check to see if a slight grade would hide the smearing, which you can still see. It was a quick grade in Redcine-x. I normally like to add my contrast in Resolve, because I think it gives me more of what i like than in Redcine-X IMHO. I paid no attention to the parade scope at all. Here is a more appropriate black level to this image with a parade scope. I always like to try to properly expose the talent and separate the mids from the blacks and the highs from the mids, I think it gives a more "dynamic" image that way. And, most of the time I never like to either clip or crush any of my channels so I always leave a little "breathing" room in the shadows and not completely crush them.


    [IMG]more black_1.1.13 by rand thompson, on Flickr[/IMG]


    [IMG]Screenshot (76) by rand thompson, on Flickr[/IMG]
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