How do you correct for stadium lights white balance flicker?

Discussion in 'Open Discussion' started by jonbrisbincreative, Sep 29, 2014.

  1. jonbrisbincreative

    jonbrisbincreative Mu-43 Regular

    76
    Mar 30, 2014
    At some high school football stadiums we play in, they have some kind of lights that "flicker" and change color temperature that is only noticeable when taking photos on continuous drive. As an example of what I'm seeing, here's two images taken a fraction of a second apart. They are basically unretouched (other than a standard preset I apply on import but that doesn't adjust white balance). You can see the drastic difference in color temperature between frames.

    How does one go about correcting for this huge difference? I shoot these in RAW so it's fairly easy to adjust but I can't ever seem to get it "right" and it causes a difference between the other photos I take because the white balance is literally all over the map.

    wb_flicker.
     
  2. kwalsh

    kwalsh Mu-43 Top Veteran

    775
    Mar 3, 2012
    Baltimore, MD
    I honestly don't know that there is a good solution to this. I believe larger venues (like a MLB or NFL stadium) do not use lights with this time varying WB. From what I've read when at such a place as you are shooting you are left with using a 1/60 shutter speed or dealing with this nasty problem.

    In theory I suppose at the start of your shooting you could take bursts of a color checker and build say ten or so different profiles to cover the different parts of the discharge lighting cycle. Then choose by trial and error the closest one for a given shot and then make smaller WB adjustments from there. Even then I suspect there will be limits to what you can do. These lights have very narrow spectral features that lead to large metameric failure. That failure will be different in different parts of the cycle.

    Worse still are lights that change quickly enough that the top and bottom of your frame have different WB :(

    Good luck, I haven't dealt with this myself but I had a friend who never did find a good solution beyond lower shutter speed - not a good option for sports.
     
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  3. jonbrisbincreative

    jonbrisbincreative Mu-43 Regular

    76
    Mar 30, 2014
    Thanks for the info. I honestly don't know what half those words mean but I picked up enough from the context to gather I'm pretty much screwed. ;)

    Oddly enough, this doesn't happen nearly so bad on my Canon 7D, even shooting at higher shutter speeds (1/320 to 1/500 usually). I only see this drastic difference on the E-M1.
     
  4. kwalsh

    kwalsh Mu-43 Top Veteran

    775
    Mar 3, 2012
    Baltimore, MD
    Yeah, that's a good summary :)

    Hmm, that is interesting. Although your examples above are at 1/640 which is faster than the 7D speeds you mention. Were your 7D shots at the same venue? It really depends a whole lot on the type of lighting being used, some stadiums no problem at all while others are hopeless.
     
  5. usayit

    usayit Mu-43 Hall of Famer

    Probably a dumb question but do cameras auto-WB between each frame in continuous mode or do they take a single auto-WB adjustment and keep that kelvin through out the burst?
     
  6. Promit

    Promit Mu-43 All-Pro

    Jun 6, 2011
    Baltimore, MD
    Promit Roy
    It's worth noting that Canon's 7D Mark II is able to retime the shutter firing to avoid this effect. Clearly you are not alone.
     
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  7. RobWatson

    RobWatson Mu-43 Hall of Famer

    I have not seen this feature in anything except astronomy software and I'm pretty sure it would not fully resolve the problem anyway...

    In these cases with a plainly white jersey being able to select a jersey and "make it white" rebalances the color in many cases to 'repair' funky color temp fluctuations. Maybe such a tool is common and I just don't know about it.

    I tweaked one as described just to illustrate the effect. Note that the screen capture is a very rough place to start! Also, the white jersey had a number of saturated pixels which also limits the effectiveness of the described method.

    wb_flicker2.
     
  8. eteless

    eteless Mu-43 All-Pro

    Jun 20, 2014
    if you shoot using continuous low rather than high it will automatically update the white balance per frame, at the cost of 4 frames per second. I generally just find something common to most of the pictures (say the grass) and figure out what number I need to shift off after sampling it to get a normal white balance, say +2000 temp and -80 tint or something like that(for grass) or +1600 temp and +20 tint for a skin tone. In this case it appears there's a decent grey on most of the players boots though, so that might work.

    It's not really ideal though, I haven't figured out an automated way of doing it yet.
     
  9. kwalsh

    kwalsh Mu-43 Top Veteran

    775
    Mar 3, 2012
    Baltimore, MD
    OK, that's really cool. Impressive to see an otherwise staid stick in the mud camera company come up with a great solution to a real world problem affecting their customers!
     
  10. Ross the fiddler

    Ross the fiddler Mu-43 Hall of Famer

    I think you'll find it would likely be up to 6 fps, which isn't too bad perhaps (depending on how quick each frame would take to focus).
     
  11. eteless

    eteless Mu-43 All-Pro

    Jun 20, 2014
    Sorry, my wording was slightly confusing, I meant the tradeoff of going to low compared to using high. High can achieve 10 compared to 6 on low, thus the trade off (cost) is 4 frames per second. Using manual focus and back button focus forces the camera to not refocus between shots and thus maintains the highest speed it can.
     
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  12. jonbrisbincreative

    jonbrisbincreative Mu-43 Regular

    76
    Mar 30, 2014
    I've been using C-AF low for all these shots so that the autofocus will work between frames. That's important in sports like this where the movement through the frame is going to be changing the distance to the camera and you have to use a wide aperture to achieve a high enough shutter speed to stop action. If the WB is also changing between frames then that could definitely explain the difference. In that case, picking a "correct" WB setting should even things out considerably. I tend to shoot in manual anyway because the camera tends to get confused with action shots where dark-colored uniforms come in and out of the frame and there are sometimes a lot of black jerseys and sometimes just a couple. The camera is smart but not that smart so I have to usually take the reins and set a baseline that I just tweak as the evening goes on and the sun goes down and we transition to completely stadium lights.

    I see the E-M1 has the ability to set tone curves. I assume those transfer to Lightroom via metadata in the RAW file. I wonder if I need to figure out the proper tone curve setting I want and save that as a preset. I'm not sure I know how to do that but surely the instruction book explains that.
     
  13. RobWatson

    RobWatson Mu-43 Hall of Famer

    Wowsers ... did someone already post this?
    http://www.sportsshooter.com/message_display.html?tid=20873

    Color problems and intensity variations explained cogently.

    "Screwed" was quite apt. Aside from using 1/60 sec shutter speed (and grey card custon WB) the only other viable solution is bring your strobes (big ones). Otherwise much work in post to only attempt to minimize the problem.


    Actually, another 'solution' would be B&W rendering! Maybe not ...
     
  14. estarkey7

    estarkey7 Mu-43 Regular

    28
    Aug 27, 2014
    USA
    There is absolutely nothing you can do. A lot of posters are saying you can correct this with shutter adjustments, but you can't because it's not a shutter/sync problem.

    The lighting used in some stadiums is mercury vapor, which by design emits a different color every half cycle. It's a full tilt pain in the you know what to deal with. I believe shooting RAW is the best formula, but it's still possible to get a shot right when the cycle is changing. Now you have 2 different color light sources illuminating the subject at the same time! That is why no matter what you do, the lighting color just seems off...
     
  15. ApGfoo

    ApGfoo Mu-43 Regular

    158
    Dec 10, 2012
    Bay Area
    I just recently started shooting raw as in earlier today since I want to increase my post processing skills. If you have Camera Raw or possibly Lightroom you can try your luck using the Adjustment Brush tool. Here's my quick and dirty attempt but I'm sure others here can spend more time and do a much cleaner job. looks like I could have used more feathering at the top edge of the grass for a less consistent look like the image on the right to keep a bit more yellow.

    Anyway the adjustment brush did not have a dial for temperature so I fiddled with exposure, brightness, color, etc. Pretty simple but very effective.

    [​IMG]

    I came across it today when trying to adjust exposure for certain part of an image(subject was underexposed) rather than the whole image itself and learned the adjustment brush was the best way so I thought that it could also apply to your situation as well. Good luck.

    edit: looks like newer versions of Camera Raw has a dial for temperature as well...