Batch XMP Exposure (MagicLantern, ETTR, day-to-night timelapse)

[Enzo De Bernardini]

Hello,

Recently I tested a few MagicLantern modules for day-to-night timelapse. The idea is to get a smooth transition between photos so that the final video has no flickering, from day to night light conditions. This modules works combined:

• Intervalometer - Manage all the sequence.
• Auto ETTR - Automatically change camera settings for slow transitions between images.
• Post Deflicker - Generates a XMP file with exposure values for fine tuning to achieve a smooth transition with last and actual image.

I would like to write a complete tutorial...perhaps when I have a little more time. Meanwhile, I recommend reading this post. If you never used MagicLantern, please review very carefully the installation instructions.

At the end of the automatic sequence we will have for each image an XMP file with the same name. The script reads each XMP file and applies a PixelMath function to adjust the exposure to all images, and save a new one. After this, if everything go well, the sequence will be well adjusted, with a smooth transition and without flickering. You can check this with Blink module.

Test Example:

• Video (YouTube) It's a test, please ignore the aesthetics, and the lack of stars :embarassed:

Tips:

• You may prefer to crop or resize the image before running the script, since the file size  is usually a bit large (xisf format recommended)
• If you apply other processes (before or after the script), be careful that they do not modify each image differently. This could introduce flickering despite exposure adjustment.
• As a last step you can use an ImageContainer to generate the final files to create the timelapse with your favorite video editing software, or Blink module. It may be a good idea to number them (file name template &count;)

I hope you find it useful. I would like to see results made from dark sites, with much more stars and the Milky Way :laugh:

Best regards,

Enzo.

PD: and if you are really happy, maybe you want to donate to PIResources O0