I thought I would start a thread on reducing vibration and jello for those of us that use the Iris+ to shoot video.

Personally, I've found the Iris+ to be very stable since the first day.  I rarely get jello, and any vibration I get is easily removed with Final Cut X.  For the most part, if winds aren't too strong, I do not get vibration.

There is plenty of information on the world-wide-inter-webs about reducing vibration in quads, but not everything is relevant to an Iris+.  If I get enough feedback and advice here, I will put together a summary.  Again, the idea is to keep suggestions specific to the Iris+.

Some quick notes of my own to get things rolling:

Definitions:

• Vibration is what one would expect.  Tiny little shaky movements in video footage.
  
  
• Jello is a sort of a wavy effect that makes almost looks like you are viewing your video through a fun-house mirror. I guess its called "jello" because it looks like jello wiggling.
  
  Note: Vibration can be fixed in post using Final Cut X or other video editing software.  Jello can not be fixed in post.

Gimbals are a must:
A gimbal is a must for shooting smooth video.  Currently your choices are:

• Tarot 2D.  
  Sold specifically for the Iris+ on 3DRs website.
  Its very good, but its 2 axis only and when doing slow vertical shoots, or even when just hovering in place, your video may exhibit small twitches back and forth (yaw twitches).
  
  
• DYS 3 Axis.
  This is what I use.  It is a pain to set up and configure (though I bought mine pre-configured and programed from xproheli.com).  Based on my research it is the best option out there.
  
  
• Feiyu-tech G3.  Some people swear by these, but I was told that they can be twitchy and so I went with the DYS.
  
  Note:  All 3 of these gimbals are marketed for the GoPro Hero 3, but I've used both the Tarot 2D and the DYS with a GoPro Hero 4 Black with no noticeable difference.

Common tips to reduce vibration:

• Balance your props.
  I assume that the Iris+ props provided by 3DR are balanced right out of the box, but this seems to be the number one recommendation for reducing vibration in quads in general.  Personally I don't have the equipment to test my props for balance so I've never done it.
  
  
• Level motors.
  On another quad I used to fly, this was important.  Make sure motors are installed correctly and level and balanced relative to one another. If you imagine your Iris+ is sitting on a level surface, and that a sheet of glass is resting on top of all 4 motors, then that sheet of glass should be completely level.  (I know what I'm trying to say, but does that make sense?).
  
  
• Use the right compression dampeners on your gimbal. 
  I was advised NOT to use the grey dampeners that came with the DYS 3 axis.  The black Tarot dampeners (that you get with a Tarot 2D) are better.  I can confirm that in cold weather, the black Tarot dampeners are indeed better.  I have not tested in warm weather yet, but eventually I will.  I wonder how much difference atmospheric temperature makes.
  
  
• Calibrate your ESCs.
  Its easy to do and it can make a big difference.  http://youtu.be/6kfVusza17I
  
  
• Compass calibration.
  This is not so much about directly reducing vibration as it is about improving flight performance.  If your compass is not perfectly calibrated you might find yourself fighting the Iris+ as you try to fly it.  This can result in the occasional jerk or snap in your video, and just generally makes it harder to keep the subject in frame.    http://youtu.be/oD9Z9IR2TNU
  
  
• IMU Calibration.
  I've never done it on an Iris+ and don't know how.  To be honest I don't even know what IMU stands for, though I've done it on other quads with great success (in terms of reducing vibration).
  
  
• Don't fly in Loiter to much.
  If you can avoid it, try not to fly in Loiter too much.  I fly in Loiter a lot because I need to, but the Iris+ is constantly making little adjustments to keep itself in place, and that can result in shaky footage if you are not careful - especially on windy days (when I need Loiter most)
  
  
  Thats it for me.  There is a lot more to go over, but I have to run to work.  As I said above,  if I get enough feedback, I will put together a summary for other new users like myself.  Just keeps things specific to the Iris or Iris+ if you can.