Summary
Details
Long Exposure Stacker can now use temporary files to store work in progress. LES decides dynamically whether to use files or memory based on the number and size of images and the available memory. It is now possible to process stacks of 100's of images using as little as 2GB of memory. There is a small speed penalty for using files instead of memory. For computers with SSDs, overall processing time is 10 to 20% longer when using temp files compared to using memory. On a late-2015 iMac processing a stack of 90 images of 50 mega pixels each takes less than 4 minutes with less than 2.5 G bytes of peak memory usage. On a mid 2012 MacBook Pro the same stack took about 5 minutes to process. (Smaller images require less memory, larger images will require more).
Long Exposure Stacker is now able to align images. This can be useful if the camera moves slightly during capture, for example, if your tripod is slowly sinking into the sand on a beach. In order to align images, there must be something in the image that is not moving—large rocks, mountain sides. Ideally these objects are well distributed across the image. The user must paint these stationary objects to identify them for the alignment algorithm.