X5 S jello on 25mm

Unbalanced props... buy some carbon fiber props.
 
T-motor 15x5 and you'll need adapters, there's a bunch of threads from this past week on them if you search.
 
I like to use lens hoods to balance the lenses and I noticed that at least on the 45 they can catch some of the prop-wash which introduces vibration and jello in some cases. I replaced the hood with a bare step-up ring to balance and the jello went away. I use a modified lens hood for my 25 though and have not seen much jello.
 
I've been using the 25mm on the X5S and haven't had any jello issues, although I am mainly shooting sports at 60 FPS 1/120. I don't use a hood, just balancing rings.