How to photograph a mural on a 21x9 ft wall in a hallway?

[nihilprism]

Hi, I've viewed this forum for years but I just joined because I seriously need help. I just finished painting a mural in oil, and I want to compose a photo of it. Advice would be greatly appreciated.
It's in a hallway on a 21x9 ft wall.
I figure I would have to take it in sections, and I am skilled with Photoshop CC. However, I am having a hard time with composition, and I don't want to wreck the original proportions of the mural.
Gear: EFS 18-135mm STM lens on a Canon EOS 650D/Rebel T4i.
I was first going to shoot on film with my Miranda, but then I realized the challenge the project posed.
My camera might have a panoramic photo option, but that seems really amateur to me. How can I get the best composition without sacrificing quality or the proportions of the mural? Thank you!

 

[tirediron]

Which Miranda?

The hallway makes this tricky; I would set up the camera in portrait (vertical) aspect with the centre of the viewfinder at the vertical centre of the canvas, and shoot in segments and stitch. Measure things out, so each segment is identical with say 20% overlap. I don't know if that will preserve the proportions to the desired degree, but I can't really thing of another way to do it if you can't move the image.

 

[Designer]

The more images you capture the more accurate the proportions will be represented. If it's important, and if you've got the time, make your photographs centered every one foot, then stitch them.

 

[nihilprism]

Which Miranda?

The hallway makes this tricky; I would set up the camera in portrait (vertical) aspect with the centre of the viewfinder at the vertical centre of the canvas, and shoot in segments and stitch. Measure things out, so each segment is identical with say 20% overlap. I don't know if that will preserve the proportions to the desired degree, but I can't really thing of another way to do it if you can't move the image.

Thank you! I didn't consider that I should make the space between shots consistent!

 

[Derrel]

Top line is the plane of the Mural on Wall (not drawn to scale.)
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Dotted lines represent two lines of masking tape, spaced as far apart as the tripod legs when set to a FIXED spread. Obviously, you get the idea. Two legs and two tripod feet placed on the closer line, one foot on the farther line. This is a 10-shot "tall" pattern.