EOS 6D shutter speed precision

[emitc2h]

Hello,

I took a few time lapses recently, shooting straight up at the sky. I got mostly clouds on a deep blue sky background and since the scene was very bight, I opted to shoot with a shutter speed of 1/1000. I realize it was a bit of a mistake since the clouds are moving a lot over each interval of 5s, and the fact the the images are very sharp (no motion blur at all) makes the video look choppy. However, there's another effect that I'm noticing which is even more annoying than the choppiness: the blue sky flickers. In other words, the brightness of the images is inconsistent from one frame to the next, and I was wondering if that could be due to varying exposure time. Anyone know what is the precision of the shutter speed on an EOS 6D camera? The fluctuations in brightness I'm seeing are of the order of 2%, and it's plenty enough to be visible in the video.

Cheers,

Michel

[Peter · Accepted solution]

For timelapse, deflicker is a very nice tool to use. .

[TTMartin]

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@emitc2h wrote:

Hello,

I took a few time lapses recently, shooting straight up at the sky. I got mostly clouds on a deep blue sky background and since the scene was very bight, I opted to shoot with a shutter speed of 1/1000. I realize it was a bit of a mistake since the clouds are moving a lot over each interval of 5s, and the fact the the images are very sharp (no motion blur at all) makes the video look choppy. However, there's another effect that I'm noticing which is even more annoying than the choppiness: the blue sky flickers. In other words, the brightness of the images is inconsistent from one frame to the next, and I was wondering if that could be due to varying exposure time. Anyone know what is the precision of the shutter speed on an EOS 6D camera? The fluctuations in brightness I'm seeing are of the order of 2%, and it's plenty enough to be visible in the video.

Cheers,

Michel

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Where you in Manual mode with a fixed ISO (not Auto-ISO)?

[emitc2h]

I was in manual mode, and everything was fixed, ISO, aperture, shutter speed, and white balance. Is there anything else that can be left floating?

[ebiggs1]

You need to use Auto ISO.  The shutter is very accurate at least it is consistent if not truley 1/1000.

[emitc2h]

But shouldn't a fixed iso deliver a constant brightness? Why would setting ISO on auto make things any better? Plus, the ISO values that are allowed are apart by way more than 2%. If anything, it will create a flickering that's even worse. I actually tried that last year while trying to capture a time-lapse of a sunset, with ISO set on auto. The transitions from one ISO setting to another are quite noticeable.

[ebiggs1]

Auto ISO is the way to do it.

 Even though you are shooting the sky with clouds, the exposure does change ... slightly.

Auto ISO compensates for that.

[Peter · Accepted solution]

For timelapse, deflicker is a very nice tool to use. .

[emitc2h · Accepted solution]

That's pretty cool! I was thinking of installing Magic Lantern, but I'm a bit worried about voiding the warranty. Maybe I'll wait until the warranty itself is void. In the meantime, some python hacking did the trick:
https://somanyslugs.wordpress.com/2015/07/01/time-lapse-geekery-flickering-brightness/