The other day I was showing a friend how to send images to be merged into an HDR in Photomatix Pro by exporting from Lightroom. When we were going through his image library, it was difficult for him to remember which images were in each sequence. He couldn’t remember if his camera was set to show the image sequence as -2, -1, 0, +1, +2 or 0, -2, -1, +1, +2. Sometimes he would take a sequence then vary the shot, and looking at the thumbnails was difficult. Rather than struggle to find each sequence, we enabled Auto Stack in Lightroom.
Stacks are images grouped together inside your catalog. We can choose to Auto Stack images by capture time in a particular folder or collection, which is perfect for grouping sequences of images for HDR together.
Select the photos youd like to Auto Stack. You can select all the images inside a particular folder or collection, even if they aren’t going to be merged to an HDR image. Lightroom uses the capture time of an image to group them together. Generally, individual shots aren’t taken quick enough together to be auto-stacked.
From the Photo menu, choose Stacking > Auto Stack by Capture Time
Choose your interval. Lightroom needs to know how much time you want to allow between images. You can set it to a 30 seconds between photos (0:00:30) or a 1 minute (0:01:00) up to an hour (1:00:00). This really depends on what time of day you were shooting your HDR images. During the day, your shutter duration is quicker and the time between images will be quicker. If youre shooting at night, your image might have a shutter duration of 30 seconds, plus 10 seconds between images. In that case, youd want to set the interval to 45 seconds.
Once you have all the images stacked, you can see how many images are in each stack by a little number in a gray box on the top left of the thumbnail or by hovering over the images. To collapse all the stacks at once, right-click and choose Stacking > Collapse all Stacks. You’ll notice that each thumbnail now has a number in the top-left corner indicating how many images are stacked together. You can expand a stack by right-clicking and choosing Stacking > Expand Stack. To quickly expand or collapse the stack, use the keyboard shortcut S.
Review the images. Auto-stacking doesn’t always work well. When Im shooting Ill sometimes take a burst of 3 photos and wait until Im in Lightroom to pick the best one. These images shouldn’t be auto-stacked, but based on the capture time, they are. So I can select the group of them, and right-click, choose Stacking > Unstack.
Auto Stack is a little-used feature inside Lightroom that can really help when youre dealing with the large number of files that HDR requires. Let us know in the comments how you use auto-stacking in your Lightroom workflow.