Kurt, it's a tire wall. I used the levels and exposure sliders in Aperture to completely black it out. The actual background in turn 5 looks far worse, which you know if you've shot there. If you haven't, then you are a good observer. These photos are only for web galleries for our paper's site, so exact detail is not too critical.
1D4, 6D, 7D2, Sony a6000 with Sony16-70, Rokinon 12mmf2, Canon lenses: 17-40L, 17-55 f2.8, 10-22, 50mm 1.4, 85mm 1.8, 70-200mm IS 2.8, 300mm 2.8 IS, 580EXII (3), 430EX, Alien Bees.