Product Review: DJI Phantom Quadcopter for GoPro (Part 2)
DIY Upgrades and Troubleshooting for Better Video
By Jeff Foster | February 27, 2013
After using the DJI Phantom quadcopter with the GoPro Hero3 for about a month, I've discovered several tips, tricks and resources for getting better photos & videos with this setup. In this segment, I share what I've learned about stabilization, calibration and experimental mounts for the GoPro to get rid of Rolling Shutter (Jello Cam). I've also learned that I'm a terrible pilot and still need a lot of practice and "flight time"!
The DJI Phantom shown here with foam "quick mount" GoPro Hero3 and upgraded to balanced Graupner CF Props
Stability... In Search Of:
I've learned a lot more about multi-rotor UAVs than I ever thought I'd care to prior to getting the DJI Phantom - but like just about everything, you find that once you start you just can't stop!
I say that not because it's an addictive money-sucking hobby (which I could see it could be very quickly) but in search of that illusive, stable in-flight video on the GoPro, you have to do a little digging... but the info is definitely out there! This is a growing industry and while many hobbyists are paving the way, more pros are starting to look at their options and trying to figure out how they might be able to capitalize on POV cameras - with the GoPro Hero3 leading the way.
I've been fortunate to learn from some highly experienced folks here too - Don Scott from DSLRPros.com, who has been supplying me with all the test gear and upgrades and is DJI's distributor of the Phantom, and Colin Guinn, CEO of DJI North America. Every time I've shown them an issue I've been having with stability or rolling shutter issues, they've given me tips on resolving them, and I'm going to share them with you in this segment.
First, let me share with you my best attempt at flying with no alterations on the GoPro mount or balancing the Phantom's props:
As you can see in the above example, even stabilizing the footage in Adobe Premiere Pro CS6 with the Warp Stabilizer and the Rolling Shutter Repair tools, there's still plenty of "jello-cam" in the video.
I've learned this is caused by two primary factors: unbalanced props and vibrations through the GoPro mount. Some have mentioned that the video mode you shoot in has a contributing factor as well, but since my battery life (and only one battery to test with at the moment) I haven't been able to test multi-modes in any one test flight with similar conditions. I plan to do this comparison in my next installment in March, just before NAB.
Testing Shock-Mount Options
While most of the mounting solutions out there for the GoPro are rigid/stationary (including the current mount provided by DJI for the Phantom) there are several DIY mounts that have been improvised that help reduce the vibrations to the GoPro from the body of the Phantom. This is a critical first step as it will surely lessen the affects of motion/vibrations from unbalanced props and sudden movement.
I've heard a lot about using sorbothane, and while I await getting some 1/4" sheet stock to create some mounts, I bought some sorbothane shoe inserts and cut them up to test. My first attempt didn't work so well as they're almost like Teflon where nothing wants to stick to it, but I was able to get some hold with Epoxy to a GoPro mount and to the body of the Phantom for at least one test flight. I used some rubber bands as an emergency "bungee" in case the vibrations broke the glue hold loose - which it did eventually, and I was thankful for the rubber bands.
While it did function quite nicely to reduce obvious vibrations, I still managed to get a bit of the "jello-cam" effect from the rolling shutter (discovered later to be caused by unbalanced props). I did manage to obtain some nice 4K stills of our horse running around in the arena though, who didn't quite know whether to run from the Phantom or stop and eat it!
But most folks using the sorbothane mounts are applying it as a bumper/washer they screw-down against with the mount. My only concern is that there is still some rigidity and vibration transfer through the screws at that point. I'm actually considering experimenting with 1/4" thick Neoprene instead, so watch for more test results in my next segment in March!
As a quick & temporary solution that I've been using quite extensively and effectively the past two weeks came from Colin Guinn at DJI, and cost less than $10 and you can install it in about 10 minutes - using sponge foam makeup discs from the drug store and some Scotch heavy duty outdoor mounting tape.
Just make a "sandwich" of the foam/tape and apply it where the original mount for the GoPro goes on the Phantom body.
Then attach the provided GoPro mount to the tape. It hold and holds quite well! Don't worry about the excess exposed adhesive surface, as while it may collect dirt and debris, it's easy to replace and probably should be replaced often if you continue to fly with this setup.
For safety, I attached a small length of picture wire to the GoPro base and the landing gear. My fear is the thing vibrating loose at several hundred feet and then falling to it's death (or that of someone/something below). Once good thing about the 5lb outdoor tape is if you do have an impact with a tree or a rough landing, the GoPro can break free and dangle without damage to the camera or the case (or the Phantom body).
No, this isn't a sophisticated solution, it's not permanent and it's far from attractive, but the closed-cell foam really works well in isolating the vibrations from the GoPro. The next step is in balancing the props so the Phantom is more stable.
Prop Balancing - Simple but Critical:
Since I'm new to the world of powered flight, I learned about prop balancing and how critical it is not only for flight control, but for stability in shooting with your GoPro. Again - I entered into this as a complete novice and just wanted to get some cool POV footage with my GoPro and not get sucked into the hobbyist factor, but quickly discovered there are some mandatory steps you must take to get better video footage - which involves some upgrades and DIY techniques/maintenance to achieve that.
I went to the local Hobby Town and picked up a prop balancing kit - not really knowing what that was and what I was supposed to do with it. Thankfully, it came with full instructions and a couple YouTube videos later I was in business. Simply using sandpaper or a craft sanding tool, you can smooth out any dings/dents in your props from "close encounters of the tree/ground kind" and equalize the weight between both ends of the props. The stock props on the Phantom are fairly soft and pliable so easy to balance - even after I've beat the crap out of them!
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