Lightroom CC, the 2015 release, adds Photo Merge to its tool set. Photo Merge comes in two flavors: HDR (Control + H) and Panorama (Control + M.) The same shortcuts work for Mac and Windows so Mac users, don’t substitute the Command key for the Control key on this one.
HDR or High Dynamic Range extends the limits in detail between shadows through the midtones to the highlights that a single exposure can show. Unlike Photoshop, which uses pixel based files to create HDR, Lightroom CC works entirely with pure RAW goodness. The merged photograph outputs as a .dng RAW file. Cool!
Shooting for HDR
In general, an HDR photo merge requires an exposure for the shadows, one for the midtones and one for the highlights. These are ideally shot on a tripod so everything lines up exactly and at two stop intervals using either the shutter or the ISO for the brackets. The aperture must remain constant. Changing the aperture causes the images to shift in focus relative to each other.
Photo Merge in Lightroom CC
While the recommended number of photos is three, it works with more when needed. In this case a series of five exposures of the Eiffel Tower at dusk has all of the shadow, midtone and highlight detail possible. The shutter speeds for the photographs are 1/15th, 1/4, 1second, 4 seconds and 13 seconds. The aperture was f/8.0. The ISO was 100. The camera was a Canon 5DMark2 with a Sigma 70-200mm f/2.8 at 200mm.
Merging the Exposures
Select the photographs to be merged. Then, either use the shortcut mentioned above (Control + H,) right click in one of the selected thumbnails or click on Photo > Photo Merge > HDR. Note that the short cut in the drop down menu has the Shift key in it. Adding Shift bypasses the HDR Merge Preview.
Note: The shift key modifier will use the last settings that you’ve chosen which can speed up the merging process. This is an option you can try.
Preview dialog box
The HDR Merge Preview dialog box has some options that are really useful particularly when shooting during the day without a tripod or when something moves within a series of exposures. The topmost check box is Auto Align. I pretty much leave this one checked even when working on a tripod. It tells Photo Merge to match up the images to compensate for minor positioning differences that might happen when releasing the shutter without a remote button.
Below that is Auto Tone. Go ahead and preview it unchecked then checked to see what Photo Merge thinks is the “right” version. Finally is the fix for “ghosting.” If someone walks in front of one of the series of exposures but not in the others, this feature will help eliminate them by comparing the frames then making the ghost disappear. This also works well on longer exposures if there is a lot of wind and things like moving branches or clouds.
This is called, appropriately enough, “Deghosting.” Click the Show Deghosting Overlay or press the O key to see the Deghosting mask. Shift + O cycles through the mask colors. The None, Low, Medium and High buttons control the amount of ghosting repair. That’s pretty much it for now. Click Merge.
The Merged File
Lightroom CC processes the files without changing the originals. Photo Merge honors Lens Profile Corrections, Black & White conversions, Sharpening and Vignettes made to the original RAW files. It ignores most of the sliders in the Basic Panel as well as any local adjustments made to them. It also forgets any cropping done to the originals. Photo Merge has the job of expanding the tonal range of the file it creates to include more shadows, midtones and highlight detail. A progress bar appears in place of the Identity Plate in the upper left corner of Lightroom while the HDR .dng file is created. That file will be significantly larger in size than the individual files from which it was made.
A quick check of the new .dng shows it named with “-HDR” appended to the name of the last file in the string.
As you use Photo Merge it’s easy to find all of your HDR.dng files by clicking All Photographs in the Catalog panel in the Library module’s left sidebar. Now click Text at the top of the window and enter -HDR. Tah dah! There are all of your Photo Merged photographs.
But wait! There’s more to come…
Of course there is just one more thing. That’s using the Develop Module creatively to take the Photo Merged .dng to its final state. Next time…Kevin is a commercial photographer from Atlanta. He works for fashion, architectural, manufacturing and corporate clients. When he’s not shooting, he contributes to Photoshop User magazine & writes for Photofocus.com.