side shot with iPhone 10 slow motion issues..

im filming in slow motion with my iPhone 10 on my side shot. I get bad crosshair shake at trigger pull. I'm using the Pro Movie app to film and its set at 1080/ 240 frames per sec.looks incredible I'm just not getting pellet travel on it... Its mounted to a Monstrum G3 6-24x50 scope sitting on top of my Benjamin Marauder 25 cal. if I knew how to post video on here id show you but I not to comp friendly.... any help would be awesome! thanks in advance.
 
I've seen a lot of videos with people using the iPhone side shot and there videos were really clear. much clearer then mine. I'm really looking for info on the system I'm using to see if I'm doing something wrong with it. thanks for the info though. I'm not sure who Matt and Ted are or where to find their videos. can you point me in their direction? thanks
 
I've seen a lot of videos with people using the iPhone side shot and there videos were really clear. much clearer then mine. I'm really looking for info on the system I'm using to see if I'm doing something wrong with it. thanks for the info though. I'm not sure who Matt and Ted are or where to find their videos. can you point me in their direction? thanks

I think he is referring to Matt Dubber and Ted's Holdover on Youtube. They post a lot of hunting videos.