Shutter shadow on photos? Canon 60D

[fotograph]

I am shooting with a canon 60d, I have been struggling with indoor basketball photos. I'm shooting in a gym (older gym), shooting manual, so the exposure is the same on each shot. But the results are inconsistant. I'm shooting continuous high speed, and some will be brightly exposed, some are darker and some are dark on one side and brght on the other. I've got at least one example where the "bright part" of the photo is on one side in the first photo and on the opposite side in the next. The gym I shoot in is older with a series of individual metal halide lights, with no florescent lights added to even the lighting, so I do expect some hot spots and some darker, but not like I'm getting and not from photos taken at the same area on the court. What do you think? Is it simply the old lights in the gym cycling frequency or is it a camera issue?

Here are a few examples, nothing has been done to these photos except exporting in LR which sized them to 900 pixels.

 

[Derrel]

I think it's the lights cycling on you.

 

[Scuba]

Yeah it is the lights.

 

[fotograph]

Thanks to you both. I've always thought that, but I noticed how it moves through the picture and it got me wondering.

 

[480sparky]

I think it's the lights cycling on you.

Uhh-Yep.

You're shooting at 1/1000 sec. AC in the US is 60Hz.

Your exposure time is 0.001 seconds, and the lights are cycling at a rate of 0.008333.

What's happening is the lights are dimming 120 times a second, slightly slower than your shutter speed. You're managing to take a shot during the short time the lights are dimming. It's so fast, human eyes cannot detect this cycling, but the high shutter speed you're using will record it.

 

[apaflo]

Thanks to you both. I've always thought that, but I noticed how it moves through the picture and it got me wondering.

You've got a worst case scenario there! The Exif data for the image you posted says the shutter speed was 1/1000, aperture f/1.8, and ISO 12,800. It also says the measured Light Value was 4.7 EV.

Typically schools with crummy lights are at least 5.5 EV, hopefully above 6. Good lights are above 7. You've got some very dim lights! And usually that also means they don't replace them often enough. In a well maintained gym lamps are replaced on a rotating basis, and they never let any of them get too old. Places that are on a really tight budget let them get so bad they sometimes flicker off for awhile! And even when not that bad the old ones have very low output and odd color, so the illumination across the entire floor will vary.

But even if the lamps are good, those old systems are powered with 60 Hz AC. So they flicker at twice that rate. With a 1/1000 shutter speed you catch 1/8th of the total 1/120 second cycle. The brightness cycles and the color of light cycles. The light directly above a given subject might be a full brightness, and providing most of the light for a single shot, and then in the next exposure that light is providing very little if any illumination and light is instead coming from the lamps to each side. And of course those lamps are also cycling, though they will be at different phases (they are almost certainly powered with a 3-phase system, so no adjacent lamps should be fully bright and/or dark at the same time).

That results in your "rolling" changes, sometimes bright in the center, sometimes bright either right or left of center.

The only thing you can do about it is shoot at longer shutter speeds. Ideally, at 1/60th of a second or slower! That would average two cycles (the positive and negative power peaks). But of course 1/60th of a second is useless for a basketball game!

So shoot RAW and post process every single shot for exposure and white balance.

 

[vintagesnaps]

Instead of shooting continuously, try getting set and framed (and make sure the camera is straight - notice the lines along the bleachers) before they start running onto the court. Maybe take some practice shots, use the lines on the floor to focus on such as the center circle (on the line closest to you). If you open the lens more you'll probably need a slightly slower shutter speed - it's a matter of figuring out what shutter speed and aperture and ISO will give you the best photos. It takes thinking about the timing, I find it's often getting set and watching and waiting til people move into the position where you want them to be, then release the shutter.

 

[fotograph]

Thank you all! I feel much better about the health of my camera!

I do try to time my shots and typically I will shoot off a three round burst. I don't know why but I have to really think about it to straighten my shots. I suppose the straightest feature in LR has made me lazy.