October 2018 Lightroom Classic CC Update Streamlines Panorama Processing
October 24, 2018
The October 2018 update to Lightroom Classic CC greatly simplified the processing of high-contrast panoramas. To understand why, you need to understand the best way to shoot such panoramas and what was necessary to process them before this update.
The most interesting panoramas often involve high-contrast lighting. By definition, panoramas have a wide angle of view. Unless the center of your panorama is front-lit (in other words, the sun is directly behind you), you’re likely to have very bright, backlit sky and dark, backlit land at one end of your panorama, and much lower-contrast sky and land at the other end. The best exposure strategy in such situations is to shoot a bracketed set of images at each camera position. Shooting a three-frame bracket set with a two-stop bracket interval will usually suffice. This strategy produces three frames: one frame exposed at the meter’s recommendation (0 exposure compensation); one frame that is two stops darker; and one frame that is two stops lighter. Be sure to use manual exposure to ensure consistent exposure across the entire panorama, as well as manual focus, ISO, and white balance.
Shoot a test sequence before the light peaks, and check the histogram for every component image, particularly the components from the highest-contrast part of the panorama. In each bracketed set, be sure that the darkest frame has good highlight detail and the lightest frame has good shadow detail. If not, adjust your shutter speed accordingly.
In April 2015, Lightroom CC gained the power to merge a bracketed set of images into a 16-bit floating-point DNG – in other words, a high-dynamic-range image that is still a RAW file, with all the editing flexibility that the RAW format implies. Lightroom CC also gained the ability to stitch these new HDR files into a panorama that is still an HDR RAW file. These new capabilities greatly simplified my approach to processing high-contrast panoramas. My old method required a complicated workflow involving Lightroom, Photoshop and a plug-in from HDRSoft. My new method, which used only Lightroom, required just two steps: merging each bracketed set of images into an HDR file, then stitching the HDR files into the completed panorama.
The October 2018 release of Lightroom CC further simplifies panorama processing by giving you the ability to combine these two operations into one step. Now you can just select all the images in the panorama sequence and choose Photo>Photo Merge>HDR Panorama (or right-click on a component image and choose Photo Merge>HDR Panorama). Note that you don’t need to edit your RAW files before merging the bracketed images and stitching them into a panorama. By default, Lightroom applies profile corrections to remove vignetting and geometric distortion. The HDR Panorama utility also turns Align Images on and Deghost off. If you want to use deghosting, you’ll need to use Photo Merge>HDR to merge each bracketed set one at a time, then use Photo Merge>Panorama to stitch the resulting HDR files into the completed panorama.
The HDR Panorama Merge Preview dialog box does give you several choices, as seen in figure 1.
The most important of these is the type of projection. I generally choose Cylindrical for single-row panoramas shot with moderate wide-angle and longer lenses. I choose Spherical for single-row panoramas shot with extreme wide-angle lenses and for multi-row panoramas. The Boundary Warp slider fills in the scalloped edges that stitching produces. I generally leave this slider set to zero and crop away the scallops after stitching, but if cropping will leave critical elements too close to the edge of the frame, you may find this feature useful. I generally leave Auto Crop, Auto Settings, and Create Stack unchecked.
The new HDR Panorama Merge utility doesn’t produce a better result than the two-step method introduced in April 2015, but it will save you time. Add it to your workflow today, and free up some time for more creative pursuits.
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