Panoramas in Photoshop

Panoramas are wonderful ways to repeal the laws of physics – at least when it comes to optical designs. Here is the issue. Your eyes can view around 180 degrees horizontally and about 135 degrees vertically. There is not a single  camera/lens system that can do that  in a single image without all sorts of distortion. Well, sorta.

Post-processing does offer a solution - panoramic stitching. Yes, I know, many point and shoot cameras, smartphone cameras and other photographic devices offer a crude version of in-camera stitching. But creating a pano in a dedicated panorama application or using the Photomerge-Panorama process in Photoshop will yield  much better results, with seamlessly smooth transitions between the component images. And, in the case of Photoshop, the process is straightforward and fairly easy. You don’t necessarily need any fancy camera, tripod, tripod head etc to do it, although I will admit that those accessories do make things easier and help improve your results.

Continue reading to see how I did the pano of the mouth of San Francisco Bay looking north towards the Marin Headlands.

I started by taking several test shots to check the histogram for exposure. I looked at both ends of the histogram to see if anything was touching either side which would have meant that I could have lost information in shadows or highlights. This would have been the time to make any exposure compensation adjustments. Happy with the results, I took my sequence of shots, being careful to overlap each image about 50% with the prior one. I also turned on the grid display to ensure that my horizon remained at more or less the same level in the viewfinder.

Once in front of the computer I open Adobe Bridge to identify and highlight the images. Using the right click on one of the images I open all of them in ACR.

In ACR I was able to look them over, pick a representative image, and apply the lens correction, clarity, sharpening black and white levels, exposure adjustment, etc to get it looking pretty good.

Then I used the Selected All button (top left) followed by the Synchronize Button to apply the adjustments to all of the images. With all images still selected, I pressed the Open Images button at the bottom right. This loaded the images into Photoshop as individual images.

The next step was to create individual layers of each image, and combine them in a single image. Photoshop provides the File-Automate-Photomerge command which brings up a dialogue where you can select the type of merge (Auto Panorama), the source of the files, which in this case I used the Add Open Files option, and checked off the Blend Images Together.

This results in the following screen - note the layers in the layer palette. They are masked to display only the part that each contributes to the entire image.

Using the Layer-Flatten Image command I merged all the layers into one file which Photoshop names Untitled_Panorama1 by default. At this point I no longer need the contributing files so I can remove them without saving them.

You can see that the horizon is pretty straight, but I did tilt the camera a bit as I changed my body position from right to left, leaving some croppable areas, and also some areas that can be augmented with Content Aware Fill.

Selecting the Crop Tool from the palette, I cropped the left and the right borders away to clean up the sides, but left a little white space above and below the image so that I could fill it and end up with a slightly taller image.

With the Magic Wand selection tool picked I clicked in the white space on the top left of the image to select it. Using Select-Modify-Expand, 

I added an 8 pixel expansion to the border. This helps ensure a seamless fill. 

Then I used Edit-Fill-Content aware to fill the white area. I repeated this on the other areas until done.

There were still a few areas that needed a little additional work - in particular the top edge and the top left corner. The Clone Brush came in handy as a way of removing the branches hanging in the air that were created during the Content Aware Fill procedure.

And this is the final product in Photoshop

That’s pretty much all there is to it. Once you get the hang of it, you can process a RAW-based pano comprised of 5-7 frames that require minimal adjustment in about 5 minutes.