LR/Enfuse
LR/Enfuse Installation Quickguide Change Log(from the Photographer's Toolbox.
You can donate from there too.)
You will also need to download the Enfuse application.
LR/Enfuse is a Lightroom plug-in that allows you to blend multiple exposures together directly from within Lightroom by using the open source Enfuse application.
With LR/Enfuse, simply select the images that need blending together and choose "Blend exposures using LR/Enfuse..." from the menu.
Example
These four images of the Basilique of Lyon (France) were taken on a tripod, using different shutter speeds to vary the exposure. The darkest image is correctly exposed for the stained glass window, and the lightest is exposed for the interior of the church. It would be ideal if we had an even lighter image, but we can sort this our in Lightroom later.
The images were selected in Lightroom, and LR/Enfuse was run from the file menu with the default settings. The result is a very natural looking blending of the images. It's slightly dark because our lightest image was still a little underexposed for the shadows.
Finally, the image is re-imported into Lightroom and a little fill-light applied.
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