The Peril of NOT Paying Attention

I finally decided to go make a photograph of a groovy old barn you can see great from the highway (but not so great from the bar ditch), on E HWY 377 here in Granbury. Pulled out the D7000, a tripod, and a wired remote. At 6:15am I shot the 5 pics to make the HDR image below (unedited other than the HDR merge, disregard the halo): 

5 shot HDR (0EV, +/-1EV and +/-2EV) and merged in HDR Efex Pro 2 with the Structurized 2 preset, otherwise unedited.

Then I walked back to the truck and decided to shoot above the gate and take another 5 shots at 6:21am for the below HDR:

5 shot HDR (0EV, +/-1EV and +/-2EV) and merged in HDR Efex Pro 2 with the Structurized 2 preset, otherwise unedited.

What I didn't notice that something had brushed my lens during the walk back to the truck. Never even crossed my mind to look, and the result is I blew that HDR, and the subsequent photographs... 

Lessons learned: 

1. Lens cap when moving through tall grass.
   
2. Always check/clean the lens after moving when walking through tall vegetation.
   
3. Shoot just the sky for a dust reference photo so clean up is easier. In this case, to me it just isn't worth it. I can shoot this again sometime when the sky is more interesting.