Well, that may have answered...

...that question.

The question being, why the hell do photos shot in the Vashon High School gym come out with such wildly different color renditions between two photos shot within fractions of a second from one another?

Example #1 (you'll need to click on the image to see the full details);


And Example #2:



Obviously these two photos were shot within a fraction of a second from one another.

And yes, (Spoiler Alert!) they were shot on Auto White Balance, which may turn out to be half the problem.

But only half.

So while the color cast in photo Number One looks pretty much OK, Number Two (particularly look at the color of the back wall) has a distinctly orangey-pinky cast to it.

W, as they say, TF?

I haven't moved; the gym hasn't moved; so why the hell is the color cast so different (and this is a relatively mild example) between the two photos?

Now, it's a standing joke that the halide lights in the Vashon High School gym are appallingly bad anyway: they're literally different colors, such that you can stand out on the gym floor and almost see no two light of the same visible color.

This is due to age and maintenance, I'd bet: when the individual bulbs have needed replacement I'm sure that no thought whatsoever was given to buying a metal-halide bulb identical to those already installed. Let's get the cheapest, and be done with it.

Add in age (halide lights change color as they get older) and you've got lighting that pretty much sucks.

But why would two photos shot within moments of one another, pointed at identical parts of the gym, have such different color casts?

Turns out the real culprit is alternating current, and the way halide (and fluourescent) lights work.

Halide (and fluorescent) lights are actually cycling on and off at 120 hertz or 120 times per second -- at least those with older non-electronic ballasts -- which I'm sure is what the VHS gym lights are.

Way too fast for the human optic system to see, but not too fast for a camera taking ten shots per second at an exposure of 250th second per.

So apparently what I'm catching here is the actual change in light output/color output of the lights as they cycle on and off at 120 hz.

OK: fine.

What to do about it?

Slowing the shutter speed down to, say, a 60th or a 30th of a second might do it, but that's not going to work for shooting sports.

So I think the strategy is to register a Custom White Balance in my EOS 1D Mark IV and 5D Mark II, and not have the camera think that it's doing it correctly when it's looking at light that's constantly flickering and thinking it's got a valid reading for Auto White Balance.

During RAW conversion and post-processing I just tell BreezeBrowser "This is what color the light is, period" instead of whatever the camera thought it was at the instant a particular photo was shot.

I think.

At least that's the Plan of the Moment(tm).