Rainbow pano

Image Description

I’m posting this rainbow pano not for it’s esthetics but as a teaching exercise, to share what I learned in creating it. We are touring Fjordland in NZ and were awaiting the the water taxi (white runabout lower right) to ferry us to a trail across Lake Te Anau. The rainbow appeared.

Had I planned this I’d have used a full frame camera with an ultrawide lens. But the plan was a 6 mile trail walk, so I had only my petite Fuji x100v. This forced me to shoot in portrait orientation and do a hand held pano.

The first lesson was that different portions of the rainbow benefit from different CPL adjustments to maximize rainbow intensity. I learned to adjust the CPL between frames. It’s intuitively obvious! The angle of sunlight on the raindrops varies across the wide arc. Had I used an ultrawide on a full frame camera to get all (or most) of the rainbow in one frame, I’d never have made this observation.

Second, rainbows shift rapidly. Doing a pano of a rainbow presents the same challenge as doing a pano of an aurora. This rainbow drifted very slightly as I shot, not enough to be evident in real time but enough to introduce incongruities in the pano merge. If you look carefully you’ll see one where the rainbow crosses the clouds,just left of center. I shot several series and I did multiple merges with each. LrC put the incongruity in a different place each time. This merge was my most acceptable.

Type of Critique Requested

  • Technical: Feedback on the technical aspects of the image, such as exposure, color, focus and reproduction of colors and details, post-processing, and print quality.

Specific Feedback and Self-Critique

Would be better if those crummy plastic water tricycles were not in the scene…

Technical Details

Fuji x100v 23mm f/5.6, ISO 160 (base ISO), 1/500"; 18 handheld frames merged in LrC perspective model, 7 masks in LrC.

Hi Richard,
that is a wonderful scene with a fabulous rainbow. Looking at your picture, I would love to stand there now and take in the scene with my own senses.

Stitching a hand-held shot panorama with moving clouds and a rainbow is a tough challenge for LR. You probably also introduced additional camera shifts when adjusting the CPL. But the overall stitching result looks good to me. Sometimes panorama software like PTGui is able to provide a better result.

However, I took the liberty and downloaded your file, opened it in PS and tried to fix the rainbow. Here is the result (I added your original image here as well, So you can switch back and forth):


Maybe you are not a PS user, but this stitching issue can’t be fixed in LR. So here is my approach:

  1. I used the Rectangular Marquee Tool to select an area of the image that includes the issue
    image

  2. I copied the selected area to a new layer

  3. I activated the Transform Tool in Perspective mode (Menu File → Transform → Perspective) and dragged the left edge of the frame slightly up until the right part of the rainbow seemed to align with the left part outside of the frame
    image

  4. I added a black mask on that layer and painted with a white brush over the problematic area until the rainbow looked good. Here you can see where my brush took effect:
    image

I hope this makes sense to you. Just let me know if you have any questions about it.

That’s a really beautiful picture. Well done!

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Your comments are very interesting to me , because I too have been processing a stitched rainbow. I wasn’t using a CPL, and your observation makes me wish I had. (Although, I’ve had some real challenges stitching wide-angle CPL images in the past due to the heavy vignetting I typically get with an ultra-wide lens.)

Fortunately in my case, I did have a wide lens (14mm on a full-frame) so I was able to have one image that included the entire rainbow to build off of. (Without that, I would have battled the exact issue you note regarding rainbow movement.)

That picture was tight though, right at the edge of the doubled rainbows on each side, and did not include the foreground flowers I wanted. I stitched images to add breathing room on the sides, and the foreground flowers. (In my case, I used PTassembler.) An additional observation is that the shape of the rainbow would change depending on the projection I used, and it was a bit tricky to keep it natural looking.

Your rainbow is beautiful, and hopefully the next one you’ll have that full-frame/ultra-wide combination with you. (I wouldn’t be offended if you cloned out the the tricycles…)

Richard, this is a great image and wonderful learning lesson. That x100V is an awesome little camera isn’t it?

I’m impressed with what @Jens_Ober did with the rainbow. Another learning lesson.

Thanks for sharing this, Richard. Very cool.

Jens, thanks for taking the time to teach me this! I’ll try to replicate it on my screen. Great teaching. NPN is terrific, and thanks also to David Kingham for developing this website. - Richard

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Richard,

Fabulous capture of the full rainbow. Beautiful. I also really like the beautiful light on the lake and the toys - great clouds!

It’s pretty hard to pick out the anamolies in the rainbow and honesty, only fellow togs and pixel peepers would ever care. But great and helpful tip from @Jens_Ober - Thanks Jens!

And thanks Richard for your tips and suggestion on the CPL - something I had never considered. I’ll have to remember both the capture and post processing tips!

Lon