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Thread: Can anyone here identify this streak of light and/or what caused it?

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    Can anyone here identify this streak of light and/or what caused it?



    I initially thought it was the trail of an airplane or helicopter flying through the scene during the long exposure. However, upon closer examination, I think it must be something else, as it strikes me as incredibly coincidental that it would originate dead center from the street light and even more bizarrely, that it would pass in front of the railroad crossing gate and not behind it!

    Both prior and subsequent exposures of this scene show no such streak and the rest of the frame looks fine, so I don't think it's the result of any problem with the back ... or at least not a permanent one. (FYI, this was captured with my P30+, clipped from the RAW image processed with the default settings of Capture One v. 6.1, downsized to 1024x768, and then saved as a maximum resolution .jpg.)

    I'm well and truly stumped. Does anybody here have any ideas? A secret military project? An anti-photography device built into the streetlight? A robotic firefly?

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    Re: Can anyone here identify this streak of light and/or what caused it?

    It's definitely a sensor artifact, probably from a corrupted read.
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    Re: Can anyone here identify this streak of light and/or what caused it?

    Looks cool though. If it were me I'd be finding a way to replicate it. But I'm strange that way.

    Reminds me (indirectly) of everyone at the moment who's doing black sun-related work on film illustrating the Clayden Effect etc.

    There is also Stephen Tillman's latest series:
    http://www.wired.com/rawfile/2011/04...hrough-tedium/

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    Re: Can anyone here identify this streak of light and/or what caused it?

    Quote Originally Posted by cng View Post
    Looks cool though. If it were me I'd be finding a way to replicate it. But I'm strange that way.[/url]
    As it happens, because I photograph mostly at night, I have plenty of images with similar light streaks in them. I usually try to avoid them, but sometimes they work, such as this one:



    However, I have no idea how to go about replicating this particular form of light streak, especially the part about how it's located in the foreground and not the background.

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    Re: Can anyone here identify this streak of light and/or what caused it?

    Quote Originally Posted by Jack Flesher View Post
    It's definitely a sensor artifact, probably from a corrupted read.
    Now that I think about it further, I'm fairly certain that it was visible when I previewed the image immediately after capture, but I didn't realize at the time that it wasn't a lighttrail from an airplane. It definitely is part of the image on the CF card, as I haven't deleted it yet and just checked to confirm as much.

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    Re: Can anyone here identify this streak of light and/or what caused it?

    Although I do find artifacts and glitches interesting in their own way, if this was consistently repeatable and frequently recurring then it would be by definition classed as a fault. This is digital after all, no happy accidents allowed.

    I just like how the line is symmetrically placed it starts and ends at equidistant points from each edge of the frame and also how it's in front of everything, very graphic. I'm a bit ambivalent about the pink candy cane colour scheme though.

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    Re: Can anyone here identify this streak of light and/or what caused it?

    Quote Originally Posted by Jack Flesher View Post
    It's definitely a sensor artifact, probably from a corrupted read.
    It seems that the blown highlight of the street lamp effected most of the line or two of pixels.

    It would be easy to understand that on a scanner or scanning back...

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    Re: Can anyone here identify this streak of light and/or what caused it?

    Quote Originally Posted by cng View Post
    I just like how the line is symmetrically placed it starts and ends at equidistant points from each edge of the frame and also how it's in front of everything, very graphic. I'm a bit ambivalent about the pink candy cane colour scheme though.
    I hate to burst your bubble, but this is only a section of the entire frame, and in reality, the length of the "glitch" is maybe 15% of the frame width. I do think it interesting that it's perfectly parallel to the top and bottom of the frame and to my mind, this suggests that it's the result of an electrical or software problem and not an optical one...

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    Re: Can anyone here identify this streak of light and/or what caused it?

    All these backs use references to map out 'bad parts' of the sensor this is handled via the software. In virtually all cases this done without the user knowing it. In 'abnormal' cases, eg. bad light, low light, etc... this process sometimes shows glitches. That can result in phenomena like this.

    Often using a next version of the processing software takes care of the issue (sometimes using an older version too).

    At least this is the case with Hasselblad backs, I reckon other manufacturers use similar processes to handle data coming from the back.

    I have also seen errors like this, 1 pixel wide straight lines that were column errors. That was due to a defect control board which was by far the most costly repair I had with any of my backs. Fixing a column error doesn't necessarily mean a costly repair, I was downright unlucky in my case.

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    Re: Can anyone here identify this streak of light and/or what caused it?

    Hard to tell without a RAW file however if the exposure on the center of that street light has values of 4-5 times more than the saturation point of the pixel (255,255,255 in 8-bit) then it may show this effect, called "blooming" which will normally look like a straight line (or lines) of blown pixels.

    This is of course just one possible cause. I would suggest calling your dealer or submitting a support case with Phase One

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    Re: Can anyone here identify this streak of light and/or what caused it?

    Quote Originally Posted by yaya View Post
    Hard to tell without a RAW file however if the exposure on the center of that street light has values of 4-5 times more than the saturation point of the pixel (255,255,255 in 8-bit) then it may show this effect, called "blooming" which will normally look like a straight line (or lines) of blown pixels.

    This is of course just one possible cause. I would suggest calling your dealer or submitting a support case with Phase One

    yair
    +1 Looks like blooming to me. Whilst these sensors are anti-blooming up to a certain saturation limit (1000x) - these are based on short exposures (usually milliseconds). Long exposure of bright light sources can overwhelm even ABG CCDS

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    Re: Can anyone here identify this streak of light and/or what caused it?

    Quote Originally Posted by Googaliser View Post
    +1 Looks like blooming to me. Whilst these sensors are anti-blooming up to a certain saturation limit (1000x) - these are based on short exposures (usually milliseconds). Long exposure of bright light sources can overwhelm even ABG CCDS
    This is interesting, especially because it's the very first time I've experienced anything like this in the 7 months or so that I've been using this back for nighttime photography and this wasn't the first time there have been very bright point-sources of light in the frame. As I mentioned, the other exposures I made of this scene before and after this one were just fine.

    But thanks for the input!

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