Lesson for the day: Know your equipment. Read the manual. A lot! I had planned this for an HDR image. I took plenty of exposures thinking I had auto-bracketing on, with the base exposure at -1 EV. I was also using the 2-second timer and mirror lock-up. Somehow that combination did not add up into bracketed exposures and I ended up with groups of three of the same image.
In my favor was that I’d set the base exposure for -1 EV so that the bridge was not blown out completely and could be salvaged in post.
Still, the HDR will be far more dramatic. I think I’ll try this same shot next week with proper exposure bracketing.