The general sequence for how I use the dropController is:
Activate mirror lock up.
Wait a second
Open shutter (camera in bulb mode)
Activate the solenoids and create the water drops.
Wait for the splash or the collision
Fire the flashes
Close the shutter
You can also use the camera with a set shutter time rather than bulb mode. This is how I used version 1 of the dropController which could not activate bulb mode on my camera. I set the camera to manual with a shutter speed of around a second. The only thing to take care with is ensuring the flashes fire before the shutter closes.
Most people online suggest a totally dark room but I have found that I can take photos in dim light. This lets me see what I am doing. To check the light I normally take a 1 second exposure before I start. If the photo is black then the light is OK. Use a low ISO (100/200) and a small aperture (F11-F16 works for me).
Used in the way it is the flash that takes the photo, not the shutter or the aperture.
Here is a typical 2 drop sequence without mirror lock up.
1. Camera Shutter.
3. Drop 1.
4. Drop 2
The camera was in bulb mode. The shutter opened at the start of the sequence and closed at the end. To use bulb mode set the camera trigger time to 0 in the dropController.
And here is a 3 drop sequence with mirror lockup.
1. Mirror lockup trigger
2. Shutter open
3. Drop 1
4. Drop 2
5. Drop 3
6. Flash trigger
7. Close shutter