Beside Lightroom CC’s new HDR Merge feature (see previous post below), Adobe has added a panorama merge function. And what makes this significant is that it’s better than Photoshop's panorama merge function. The reason is you can edit the stitched image in the Develop module as a raw file. In Photoshop, you edit only with the usual gamma-corrected image file. Raw files provide more editing latitude; and, as a rule, you should do as much possible of your editing with the raw converter before transitioning to Photoshop. Admittedly, that advantage may not always be apparent when dealing with a properly exposed image that doesn’t have problems in the dark tones or highlights. But if you have highlights or shadows that you need to dig out any detail from, it's better to do that in the raw converter. I’ll demonstrate that shortly with a few example images.
The panorama merge function in Lightroom is a snap to use. Adobe has a short tutorial (click here) that explains everything, including how to do a HDR panorama merge. To test out this new feature, I compared a panoramic image created in both Lightroom and Photoshop of the Queen Anne Cottage in the Los Angeles County Arboretum. I also created a HDR panorama to see how well it performed. By the way, if the image seems vaguely familiar, remember the opening dialogue of a long-ago TV series: The plane! The plane!
Routine PanoramaI started with a two-frame panorama that was properly exposed with little or no shadow and highlight problems. For the Photoshop version, I used the Camera Raw Filter and duplicated the same settings used in the Lightroom Develop module. In this example, the raw converter's advantage in Lightroom doesn't come into play that much. Both images are essentially identical, and this is likely the case for most evenly-lit and properly exposed panoramic images.
All the panoramas were merged using the Cylindrical layout option, which I find is best for most my panoramas. However, you'll lose a portion of the image after cropping, and that's a problem if the scene was tightly framed. In that case, you may need to use the Reposition option in Photoshop, but for some reason that wasn't included in Lightroom. The problem with the Reposition option is its propensity to create artifacts, especially if the camera was tilted when panned. Photoshop has tools to deal with some artifacts and you can click here to read more about them. The best solution, though, is always allow plenty of crop room when composing a panorama.
Lastly, I noticed that the stitched panoramic file resulted in a .dng format (Adobe's open-standard raw file format) and not your camera's proprietary raw format. Not an issue for me since I convert all my Canon raw files to .dng anyway.
|Lightroom CC Panorama Merge|
Excellent results and no stitching artifacts.
|Photoshop 2014 Panorama Merge|
Both Lightroom and Photoshop are essentially identical.
Highlight and Shadow Recovery
In this example, I used a 3-frame panoramic shot of the same scene. One series was shot at +1.33EV overexposure and another at -1.33EV underexposure. This intentionally created some problematic highlights and shadows that I then attempted to extract detail from. The image below shows which highlights (blue-circled cottage roof) and shadows (red-circled palm trees) I worked on.
I'll demonstrate the recovery difference between Lightroom and Photoshop within the blue-circled
highlight area (cottage roof) and red-circled shadow area (between the palm tree trunks).
In this example, the Develop module and Camera Raw Filter settings were identical. The Lightroom version has better overall contrast and detail in the highlights, plus better texture in the white plastic tarp. To read more why editing in raw is better, see my post on Exposing-to-the-Right. There, I discuss the advantages of a linear-data file (raw) versus a gamma-corrected file (Photoshop). There are other reasons too, such as a special highlight recovery algorithm in Adobe's raw converter.
|Lightroom Highlight Recovery|
Better overall contrast and detail, especially in the white tarp's texture.
|Photoshop Highlight Recovery|
Maybe a bit more fiddling in the Camera Raw Filter could even things
up a bit more, but fundamentally, Photoshop just has less data to work with.
At the dark end of the histogram, the differences are more noticeable. In the Photoshop version, I had to apply additional shadow recovery to the Camera Raw Filter in an attempt to even the difference. But in spite of the additional tweaking, the Lightroom version is still noticeably superior at rendering the shadow detail while the same detail in the Photoshop version is blocked up. In addition, the overall Photoshop image (including the shadow detail) was a little too contrasty.
|Lightroom's Shadow Recovery|
Lightroom does a really a great job! Additional editing
could perk up the contrast and saturation a bit more
and still retain good shadow detail.
|Photoshop's Shadow Recovery|
Blocked-up shadow detail and too much contrast,
I didn't bother to compare the HDR panorama performance between Lightroom and Photoshop since Photoshop's 32-mode has gone squirrely in their latest 2014 version (at least on my computer). Nevertheless, I tested how well it worked in Lightroom, and the results were excellent.
Now there are two ways to process a HDR panorama shot. You can stitch all the frames for each exposure, then combined them in HDR. Or, first combine the exposures for each frame segment in HDR and then stitch them into a panorama. However, only the latter will work in Lightroom, and for that matter, only in Photoshop and Photomatix 5 as well. The reason is when you stitch each exposure frame set, each set results in a slightly different size (by only a few pixels). That stops Lightroom and Photoshop dead in their tracks, and while Photomatix will merge the frames, it generates weird artifacts. Only HDR Efex Pro 2 seems to cope with the slightly different image sizes without a hiccup.
The reason I bring this up is because, intuitively, I prefer to combine the stitched panoramas in HDR. One reason is I worry that first combining each segment into HDR before stitching may produce slightly uneven results between the panoramic segments, especially in luminance. Any differences in luminance will become apparent in the sky after they're stitched. Of course, as already mentioned before, you can repair the artifacts in Photoshop, but who needs the hassle. But the biggest reason is I want the ability to fully edit the whole panorama in 32-bit mode. Yes, I could edit each segment in 32-big mode, but that's both awkward and may increase the chances of uneven frames.
Nevertheless, simply merging each segment into HDR (without, of course, any additional editing in 32-mode) and stitching them into a panorama produced an excellent image, at least for this example. And as a consolation prize for losing the 32-bit editing capability, the stitched file at least remains a linear file. However, this image wasn't particularly challenging and a high-contrast sunrise or sunset scene may beg for 32-bit editing capability. Then the only recourse I can see is to stitch each exposure series in either Lightroom or Photoshop (probably doesn't matter which) and use HDR Efex Pro 2 to edit the entire image.
|Lightroom HDR Panorama|
Results were great with no artifacts (HDR or stitching) and even sky illumination. Highlight
and shadow details are excellent. A little more editing will brighten up the image even more.
The preceding discussion was as much about Lightroom's new panorama merge as why editing in raw is important. But I needed to emphasize the latter to illustrate how nifty the new Lightroom feature is. Does this replace Photoshop's panorama merge (aka, Photomerge)? I'd say pretty much so. I'm hard-pressed to think why you would ever want to circumvent editing in raw. If Lightroom's merge did create any stitching artifacts, you can still fix them in Photoshop after you completed the bulk of editing in Lightroom. The only reason I can see to use Photoshop is for the Reposition layout option; but proper composing should avoid that need.