Conesus Lake does a "Ring of Fire" event every 4th of July weekend. The event is bunch of well-to-do people with lakefront property engaging in a pissing contest about who can spend the most on fireworks. It makes for a quite impressive show. I have friends and family that live on / near the lake, and have previously shot the event.
This year I had the best access I've ever had - a deck built on a bluff that jutted out over the lake a bit. The best I had before was a hill about a quarter mile inland. From this vantage I could shoot just about everything on the far side of the lake, and up and down the side I was on for a good half mile or so.
I was concerned that the deck, made of engineered (plastic) boards, combined with wind and close proximity concussive blasts from the fireworks would not make for a stable enough platform for long exposures. I did a few test shots with mixed results, then ended up deciding it would be good enough, if I kept the exposures relatively short.
The sun set, and people started shooting their fireworks. It was a very impressive show. I was immediately not happy with my results. It didn't feel like the deck was moving, and I was really the only person that could be affecting it (and I wasn't). I have a very hefty tripod, and I even went as far as to tighten down a few screws, thinking maybe that was to blame. The results did not improve.
I ended up blaming the deck and retreated. There were some other people on the deck, and I figured either their movement or the concussive blasts from the fireworks were shaking it enough to wreck the shot. I finished the night using shorter exposures, not wanting to retreat from the prime location to which I may never again have access.
I knew the shots were not going to be great, and I delayed even looking at them a few days. When I did get around to reviewing them, as I paged through, it suddenly dawned on me: it was my fault. 100% my fault. Not the deck, nor the kids, nor the explosions were to blame. I was so damn concerned with factoring in all these new one-off environment variables. I missed a VERY basic, obvious, ubiquitous source of camera shake - mirror slap. I had failed to account for it. Normally, this is done by locking up the mirror. In the case of my D80 (what I had with me that night), it is CSM31 - Exposure delay mode. This inserts a 0.4 second delay between the mirror kick and the shutter release.
I knew this. I've used it before. But I failed to even THINK something this obvious would be my culprit because I was so damn busy searching out a source unique to the scenario. Moral of the story = title of the post.
Oh - one last thought: This is EXACTLY why we don't do events. I make a bonehead mistake like this, and it wrecks a night of shooting some hobbyist photos. Even if I intended to turn any into wall art and sell them here (which I didn't), I'm not "out" anything but the opportunity. Could you image how a bonehead mistake this this would go at a wedding? "Sorry, father of the bride. I know you torched several thousands of dollars for these pics, but I made a small bonehead mistake, and...well...some of 'em still turned out okay." That's not a conversation I ever want to have, because I'm pretty sure it ends with either a right cross or a lawsuit, and I'm not particularly interested in being on the receiving end of either.