This is the original picture. You might ask, what the rainbow? I don't see one.
|f/6.3, 1/100, ISO 800|
Do you see it now?
What about this?
Do you feel like you are in an ophthalmologist's office?
The rainbow was barely visible in the original pictures, but with some editing and playing with the contrast it showed up more. I tried different settings on my camera and nothing came out like a rainbow should look. In this case, I had to rely on editing. As you can tell, I had too much fun with the contrast editor.