The activation of the speedlights can be controlled via the camera or it can be controlled directly from the drop controller. If you wish to use the camera for control you will need to have a either a master speedlight or a wireless controller attached to the camera hot shoe either directly or with a hot shoe adaptor. This means that the flash will fire when the camera’s shutter is fully open. Some controllers recommend that if you are using this method it is best to set a slow shutter speed to avoid capturing just a black image or black bars. It is possible that the slow shutter speed may require you to work in low light to avoid capturing any ambient light.
For this reason I prefer to have the controller directly control the flash activation. This allows me to use the camera’s fastest shutter sync speed so that I can avoid any ambient light issues. However, this method requires entering the camera lag time into the controller or the software. When I used this method to find my shutter lag I used a MJKZZ controller to determine the time but the process would be similar for any controller, just different methods to enter the data into the software such as my current dropcontroller .
To find the exact lag setting I set the controller’s flash delay to “0” and with the flash connected direct to the controller I started taking a series of photos (of the controller) in increments of 5 milliseconds for the controller’s lag time setting. Once I started to get a photo with a black bar I changed the increment for the lag to just 1 millisecond until I found the ideal lag time. This was the value I entered permanently into the controller. When I tested my camera I had just 3 timing values that produced a full image and no black bars. I just used the middle value of 55 milliseconds
The only caveat was that I had to ensure my camera was always in same wake or pre-focus state. I was able to do this using either camera settings and later I used a controller cable that activated a pre-focus signal prior to the shutter signal.
There is websites that list camera lag times and that can provide a good starting point for confirming your exact time.
I know that many will find it easier to control the flash via camera because it is easy to set up but there is the possibility of changes in camera shutter lag that will alter the flash activation – and because the solenoid settings are isolated from the camera/flash timeline there can be different capture times. I just like the accuracy of connecting direct to the controller especially when setting up the synchronisation of all the solenoids.