On a recent trip to Tenerife, I found myself shooting quite a number of panos, due to the island’s abundance of beautiful landscapes. However, when I got back to the hotel and started processing the images, using Photoshop’s Photomerge function (File>Automate>Photomerge), it quickly became clear that there was something PS didn’t like about one particular series of photos, and so what I ended up with were two separate panoramas within one file!
Now, when taking the shots, I made sure to overlap each image by at least 40%, to ensure that there was sufficient detail in each shot to relate it to the next in the sequence and also made sure that my camera was set to manual, so that every shot would be taken with the same settings, therefore stopping any exposure variations as I gently swung my camera from one side of the scene to the other. No matter what I tried though, nothing would make the process work!
Stitching the pano manually seemed to be my only option then and, luckily, it’s a fairly simple procedure to either correct an erroneous, partly completed photomerge or stitch the pano from scratch yourself.
Correcting a problem with Photomerge:
So if you’re presented with a disjointed photomerge, the first thing to do is select the relevant image layers in the layer panel that had not successfully merged and then reduce the opacity of them all to 60%. You can do this by either using the opacity drop down menu above the layers panel, or by simply hitting the ‘6’ key on your keyboard (other numbered keys will drop the opacity similarly, i.e. 4-40%, 5-50%, etc.).
Once the opacity had been reduced, drag the opaque layers over the image above it, so that the features at the far edges of each set are roughly aligned (it doesn’t need to line up perfectly, as this will be corrected later). Having dropped the opacity, lining the layers up becomes much easier. Next, raise the opacity back to 100% by hitting the ‘0’ key (or, again, you could use the slider).
Then click Image>Reveal All, which automatically expands the canvas to show the whole image.
Next, to match the layers perfectly, select Image>Auto-Align layers.
Finally, once they are aligned, select Image>Auto-Blend layers, to get rid of the harsh edge in the centre of the image.
Once that’s complete, all that’s left is a little judicious cropping and it’s job done.
Manual Stitch from scratch:
When starting from scratch, my preference is to open all of the files in to Camera Raw, making any global adjustments required to them all first, then opening them all together in to PS.
Once you open the images in to PS from Camera Raw, you’ll see that the images are loaded in to their own workspace tab, allowing you to cycle through them using the tabs at the top of the window.
Firstly, click and drag the second tabbed image out of the main frame, to create a separate window for it. (You can work from either the left or right for this, but my preference is to work from left to right, as that just seems to make more sense in my right handed brain… feel free to mix it up if you’re a left hander though!)
Then, simply drag the layer from the newly separated image on to the first image in the sequence.
Once you’ve done that, the process, as described in the photomerge piece above, is exactly the same (i.e. Lower the opacity, roughly align the two images, raise the opacity back up, reveal all) and then just repeat with the next image, dragging its tab out of the frame, etc..
Once all your images are roughly lined up, Auto-Align and Auto-Blend the layers then crop as appropriate and Robert’s your Mother’s Brother!
As a final point, when you’re happy with the layout and crop of your image, it’s worth remembering that if you shot your images in raw, then your full image is still a raw file, meaning you can go back in to the Camera Raw filter and make some more tonal adjustment to the image as a whole.
I always prefer to try and bring the sky back in a little if it’s blown out, by dropping the highlights slightly and reducing the blue Luminance slider under the HSL/Grayscale menu. Add a little contrast, clarity and dehire and, voila, you’re done!