Brightness of images varies by 17% ??

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Glynnr
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Joined: 02.01.2017 03:39

Brightness of images varies by 17% ??

Unread postby Glynnr » 09.01.2017 22:41

Hi

I am a newbie here and I have searched here for answers on the following without success.

I am shooting quite a deep subject, around 100mm front to back, using manual focus, fixed aperture and fixed shutter speed with studio flash lighting the subject. The only moving element is the camera...

Each stack is giving a warning triangle that tooltips to "Brightness of images varies by 17%. You may get better result by using manual exposure on your camera and stable lighting" - ie the setup I have already...

Can anyone shed any light on this?

Thanks

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Stas Yatsenko
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Re: Brightness of images varies by 17% ??

Unread postby Stas Yatsenko » 10.01.2017 15:32

Either ISO was Auto, resulting in exposure variation. Or, if the flash was mounted on the camera, it was moving closer to the subject (or further away from it) with each shot, illuminating it differently from each position.
That is not a critical problem, if the results looks OK then it probably is OK.

Glynnr
Posts: 4
Joined: 02.01.2017 03:39

Re: Brightness of images varies by 17% ??

Unread postby Glynnr » 14.01.2017 02:57

Hi

Thanks for this.

Unfortunately the ISO was fixed and the lights were on stands and static. The only moving part was the camera.

What is the software analysing to determine the brightness and when you say it is not a critical problem is the message effectively only a warning / observation and the stacking process will always have completed?

G

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Stas Yatsenko
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Re: Brightness of images varies by 17% ??

Unread postby Stas Yatsenko » 16.01.2017 15:56

Yes, the message is just for your information and does not in any way alter the rendering process (nor means that it was altered).
It could also be that as the well-lit subject takes larger up a lager part of the frame area when the camera moves in closer, it is perceived as increase in exposure. I believe it is calculated simply as arithmetic average of pixel brightness. We might replace it with a more advanced calculation method in the future.

Glynnr
Posts: 4
Joined: 02.01.2017 03:39

Re: Brightness of images varies by 17% ??

Unread postby Glynnr » 05.02.2017 00:56

Thanks


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