JeffT Loc: Central NY

I shot a Colorguard competition in a gym this weekend. I set a custom white balance before starting using an Expodisc. I have shot in this gym numerous times before so I was fairly familiar with the gym and its lighting. I shot in manual and AI Servo focus mode. I was shooting both Raw and jpg files on separate cards. So here was the problem: About every other jpg picture was a different color temperature than the previous picture. I went to the raw files and confirmed that about half of the pictures were at 3350K and the other half were at 3800K. So basically the camera would record a picture at 3250K then the next would be at 3800K and the third back to 3350K. I think this was one of the first times that I have checked the jpgs if I shot them at all. I have generally done a color adjustment all raw pics at the same time so I haven't seen it before.

Anyone have any idea why the custom white balance would bounce back and forth between two color temperatures?

While in this case I could easily go to the raws and adjust the WB to the 3800K (with I preferred), I would like to figure out the issue. I have a weekend long Colorguard competition to shoot where I will be shooting 40 teams with about 150-200 shots per team, so raws add up to a lot of disk space quickly. Also, in burst mode I have to be careful of not filling the buffer and missing shots when in raw.

TriX Loc: Raleigh, NC

I have had exactly the same issue with a 7D under identical circumstances - a high school gym that I was familiar with, and subsequent, closely spaced frames (shot on high speed) were different color balance. My (untested) assumption was that it was 60Hz flicker from the lights which appeared to be Halide. I thought the MKII had a flicker sync/reduction feature - I wonder if it was engaged in your case? I'll be very interested in the responses you get from others.

JeffT Loc: Central NY

Thanks for that response. It makes a lot of sense. With the 7DMkII I have upped the iso and been shooting at a faster shutter speed which could help explain why I never really saw the situation with my older 7D (of course I don't remember looking at jpgs often). I have generally set a manual color balance (such as Cloudy) and shot a grey card then adjust my WB as a group in post using the grey card as a reference.

The anti-flicker setting was not engaged. I'll have to give that a try. The one thing that bothers me about the potential explanation is that it was just about every other picture even when I moved from one scene to another. You would think that at some point you would get two on the same temperature during a 200 picture series of pictures.

SharpShooter Loc: NorCal

Jeff, I have one possibility for you. Did you use anti-flicker? Or maybe it wasn't even flicker lights. But if not, could the light balance be thrown off by the highs and lows of the flicker? Just a thought! Good luck. ;-)
SS

JeffT Loc: Central NY

Based on some quick research I did based on TriX's comments, I found that flicker seems to result in uneven banded lighting that is somewhat random in where it occurs in the frame. In my case the color temperature variance was very consistent, either 3350K or 3800K. If it was flicker I would think that the color temperatures recorded by the raw files would vary somewhat based on the the flicker was affecting individual frames.

TriX Loc: Raleigh, NC

If it's flicker (affecting color temp), I would think it would be affected by shutter speed and the fps of the sequence. I'll post two of my shots (with EXIF data) later - I'll be interested to know if they look anything like yours.

JeffT Loc: Central NY

Here are two back-to-back pictures that are representative of the two color temperatures that I was getting.

Black Bart Loc: Indiana

Call Canon tech support.

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

Here is your answer:

http://photo.stackexchange.com/questions/4115/do-fluorescent-lighting-and-shutter-speed-create-a-problem-with-color-cast

And this is the tool you need to get consistent results, at exposures less than 1/100

https://www.youtube.com/watch?v=NDtebpvATzc

Most consistent results will be with speedlights or monolights. Expodisks can be unreliable in some situations. The frames per second has no effect on the color temperature of the individual image. And no, your camera is not broken. You don't have to call Canon.

twowindsbear

Here's my WAG:

You have activated a 'WB bracketing' mode on your camera. Just turn it off & you'll be fine.

wcmoorejr Loc: Birmingham Alabama

Jeff,

Try enabling the anti-flicker on your camera and it should correct the issue. You will loose a bit of speed on your FPS because it will only shoot when the light is correct but the 7dII is fast enough to compensate.

Regards,
Willie

mwsilvers Loc: Central New Jersey

I think the Flicker feature would have resolved your issue. You don't need to keep it on all the time, but you should at least activate the Flicker warning in the viewfinder. It blinks off and on in situations where the Flicker control is needed. I keep the Flicker Control features in one of my two Star menus so I can access it quickly if I need it. However, if you've shot similar events previously in this same space and this did not occur then there might be other issues at play here. Without knowing all the settings you were using it might be difficult for us to pinpoint it.

mwsilvers Loc: Central New Jersey

Not every issue requires a call to Canon. In general first level support isn't even prepared to answer questions like this except to tell him to turn on the Flicker control. It makes sense to work through the most obvious possibilities first and then call Canon if the issue can't be resolved.

JeffT Loc: Central NY

I experimented a bit with a fluorescent light at home and could demonstrate the flicker issue. It showed up as uneven yellowing in the horizontal direction when holding the camera in landscape mode. This was consistent with the examples I have seen online. When the Flicker Control was enabled the camera was able to deal with the the light flicker.

When I look at my shots posted above, I see something different. If it was flicker I would expect to see uneven yellowing across the picture from left to right or right to left (since these are in portrait orientation). The pictures appear to be consistent across the entire frame. If you look at the white stripes in the uniforms of the two girls, they appear to be the same color temperature for both girls in each frame, but different between the two pictures. The grey floor also appears to be a uniform color, but warmer in the second picture.

I have never (intentionally) used WB bracketing, but a quick review of what it does revealed that with WB bracketing, you get multiple version of each picture that are the same except for different WB applied to each version. In my case I was not getting different version of the same picture, so I don't think that was the reason.

I think that I will figure on shooting in Raw so that I can set the WB of all pictures to the same color temperature in Lightroom. I should be able to experiment a bit with Flicker control in the gym before the start of the completion.

amfoto1 Loc: San Jose, Calif. USA

The reason that happens is fluorescent (and sodium vapor, mercury vapor) lighting cycles on and off at a rapid rate. In the U.S., it's 120Hz or 120X per second. In Europe and some other part of the world it's 100Hz or 100X per second.

This cycling of the lights usually isn't visible to us, but the fast shutter speeds of the camera certainly can capture it and camera WB and metering systems simply aren't fast enough to correct for it.

The cycling of the light not only changes brightness, it also changes the color of the light. That's why you are seeing the effect in your images.

Except for your 7DII, which introduces the new "Anti-Flicker" feature that others have mentioned above. Try that and you'll see less trouble with the lighting. The camera will time itself to only fire at the peak of each light cycle.

You did everything else correctly. Your best bet was to shoot in manual mode. And setting a Custom WB was probably a good idea, too. (To se Custom WB, I use a Lastolite EZ Balance target or Warm Cards instead. Two of my Warm Cards are designed specifically for fluorescent lighting.)

Yes, if not already doing so it's also a good idea to shoot RAW (or RAW + JPEG if you have plenty of memory cards) so that you can more easily adjust the color of your images in post-processing. However, you likely won't be able to simply batch correct them all to the same setting. That may correct some, but likely will throw an equal number of the image out of adjustment. That's because the color of the light is actually changing.

You'll find using the Anti-Flicker mode reduces your frame rate a bit... and it will change the timing of the shutter release slightly, might feel like a little bit of "shutter lag" at times. But it's better than the alternative methods of dealing with FL lighting, which are: use flash as your main light source, or reduce your shutter speed to 1/30 or slower to try to capture the full cycle of the lights relatively consistently, or just take a ton of extra shots to increase the odds that some of them will be okay and plan on trashing a bunch.

More info about the 7DII's Anti-Flicker mode here: http://www.learn.usa.canon.com/resources/articles/2014/eos7dmkii_antiflicker.shtml

And here: http://www.the-digital-picture.com/Photography-Tips/flickering-lights.aspx

AFAIK, the 7DII is the first DSLR to have the Anti-Flicker feature. The second link above has some test shots with and without, illustrating how effective Anti-Flicker can be.

I might experiment with Custom WB, the camera's Fluorescent Setting and Auto WB. I'll also be experimenting with the two different FL Warm Card targets I've got, with Custom WB. Compounding the problem, there are different colors of FL light and little consistency (except for the more expensive type that's stabilized especially for photographic use).

Plus, the venues I'm shooting use more sodium vapor lighting, than fluorescent. Though the flicker problem is similar, the WB for that has to be handled differently.