Turn Off IS/VR

Your shutter will be open for up to 15 seconds, so you’ll be on a tripod, and the last thing you want is the tiny motor inside your lens searching endlessly for vibration. That can actually cause vibration when you’re on a tripod, and with any tiny bit of movement, you’ll take a hit on sharpness. And, yes, there are a few newer lenses on the market that have a built-in feature that senses when your camera is on a tripod and they disable the vibration reduction/image stabilization feature, but they are few and far between. If you’re not certain that your lenses have this auto off feature, just move the switch for VR/IS on your lens to the off position. Sharper shots await.