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Annular Eclipse Image Sequence: Matching Image Brightness?

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#1 AZJohnnyC

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Posted 22 October 2023 - 08:59 AM

Hi all,

 

I'm trying to improve my processing of the Oct 14,2023 annular eclipse images.  I wonder if there's a way to match image brightness between hundreds of these images.  For deep sky objects, I'd batch process using PI's LinearFit, but I don't imagine that this would work with the shadow of the moon in constant motion over the sun. Is there some other way of matching image brightness across my solar eclipse images?

 

Thanks for any help that you can offer.

 

- John



#2 JayElDee

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Posted 24 October 2023 - 05:02 PM

I used Lightroom on the individual images, and balanced exposure to uniform brightness and I corrected the color. Then I brought them all into PS as layers to merge them together. Then "selected" copied and pasted, using free transform to get it looking right.

Then, I had taken a picture of the San Carlos Cemetery the day before to use as a foreground, and pasted the sequence onto it.

Totally contrived, I admit, but I like it, and the San Carlos cemetery was prob just a quarter mile from my viewing spot in the parking lot of the Nativity of the Blessed Virgin Mary churchannular%20sequence-101-X2.jpg


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#3 AZJohnnyC

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Posted 24 October 2023 - 08:29 PM

Thanks JayElDee,  

 

I love the layered image.  The muted overall brightness works beautifully with the eclipse sequence.

 

So I'd like to understand what you used in Lightroom to achieve uniform brightness across all of your exposures.  I use GIMP.  Maybe there's a roughly equivalent tool in these two programs.  Would you mind elaborating on how you did this?

 

Thanks in advance,

 

John



#4 JayElDee

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Posted 25 October 2023 - 10:09 AM

It was the simplest part of the process.

 

I shot manual exposures every 5 minutes on a stationary camera with a 70mm lens (24-70).

 

I manually adjusted exposure in the camera to get something I thought would be usable. I used that exposure throughout the entire sequence.

When I imported them into lightroom, most were pretty evenly exposed, though maybe a little under exposed and more orange than I would like.

 

The images of the sun straight out of the camera looked a bit orange , so first I increased the exposure turning the sun more white. I wanted a yellow "sun color" though, so I played with the color temperature of the sun images to get the yellow.

To make them even in Lightroom, I simply increased exposure on the ones that were a little under to match the ones I thought were proper.

The shots just before and after annularity required more of an exposure bump up, the one farther away less so, and the ones in the early and late phases served as a guide for how much to increase exposure, just so, to my eye, they looked equally bright...IOW nothing fancy, just eyeballing it and changing exposure in the computer.

 

I tweaked the whole image after the composite using masks, but that was primarily on the landscape part of it, not the sequence.

 

It sounds complex, but it wasn't. I increased exposure on all of the "suns" to make them all even—eyeballing it— then changed to color temp to make them yellow.

Thanks!


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#5 Cajundaddy

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Posted 03 November 2023 - 09:26 PM

Yep I ran a time-lapse of 500 images every 20 seconds with clouds going in and out.  I used the manual settings from the day before under full sun so most were somewhat underexposed through the clouds.  I chose one frame and adjusted the exposure and color to my liking and then simply copied the changes and pasted to all of the other frames.  There may be a way to do this globally but I could not find it so I pasted my changes to each, one at a time.  The result is a time-lapse series with consistent color and exposure across all frames. 

This is the result after matching changes.  Note that right at and just after maximum the clouds really thickened and I got zero data.  I tossed all of those frames resulting in some skipping in an otherwise smooth time-lapse.  A good rehearsal for the April 2024 eclipse.

https://youtu.be/I-Y...ybdjJUULhZSv4MY


Edited by Cajundaddy, 03 November 2023 - 09:37 PM.


#6 JayElDee

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Posted 08 November 2023 - 10:01 PM

Nicely done, Vanguard. Thanks


Edited by JayElDee, 08 November 2023 - 10:01 PM.




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