Set the camera to manual focus and ensure the focus is set correctly.
Find the middle exposure
Set your camera to manual and set the ISO and Aperture for the effect you’re hoping to achieve. Next, set the shutter speed so that the exposure is correct.
The easiest way to do this is by using the internal light meter built into the camera. First of all, make sure the meter is set to Matrix/Evaluative metering (see Theory section). Next, roll the shutter speed wheel until the line on the light meter lines up with the middle, marked with a “0”. Make sure this exposure is at least 1s.
Set the camera to bulb
Set the camera to Bulb. This is usually found on the mode dial as a B or by setting the camera to Manual and scrolling past the 30 second shutter speed.
Enter the settings into Triggertrap Mobile
Set the middle exposure you just figured out on the top wheel of this mode.
Next, set the number of exposures. We find that you’ll want at least five exposures to give you plenty of flexibility. If you’re shooting a particularly contrast-y scene then you might want to consider shooting more than 5 shots.
Finally, set the EV Step, we find one stop works really well.