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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My first test flight with the newly balanced props went fairly well, despite heavy wind gusts that day – that eventually forced a rough landing in the parking lot, as you'll see the results below. Even though the Phantom is being tossed around in the wind, the “jello-cam” is almost completely eliminated… and I slowed-down the frame rate in editing so you may enjoy the crash sequence. *grin*
The next step was to upgrade the props (and not fly on windy days).
Don at DSLRPros.com sent me a set of Graupner CF props to try out and see if they helped. They're just slightly longer than the stock props but more rigid and reinforced with layers of carbon fiber for strength.
They aren't a direct fit and need to be slightly bored out to fit over the rotor shafts, plus you'll notice the edges are a bit rough from manufacturing as it's important to balance them prior to installation.
The Graupner pops didn't appear to be marked as to CW/CCW rotation, you'll have to match up with the stock props you have installed and be sure you are replacing them in the correct position or your Phantom will not fly.
I used a 7/32 drill to slightly bore out the hole in the Graupner prop which gave me a really nice, snug fit. Screwing on the prop to the rotor shaft as if it were self-threading to a snug fit and replacing the lock-down nut with a wrench.
After all the props were installed I took it out to a local park for a test flight. The results of my testing were that even minor improvements such as a simple foam mount to reduce vibrations and balancing/upgrading the props make a significant difference in the quality of your video capture on the GoPro. While there is still some rolling shutter apparent in the glare on the lens (caused by the shadows cast from the props) I'm going to be doing further testing with frame rates/resolution and the application of ND filters on the GoPro to see what the best combination is.
If you do some searching in the UAV and multirotor forums, as well as YouTube, you will find many DIY applications of mounting a GoPro to just about everything – with just about everything! Since this is a booming industry, I think we're going to see manufacturers taking this a bit more seriously as the demand increases – including options for balanced gimbals and more advanced flight controls that already exist on higher-end UAVs.
Crash Test, Dummy
Indeed, I've had a few “incidents” with the Phantom since I first took to the skies with it, but despite my lack of control, the Phantom is amazingly resilient and forgiving! The construction of this quadcopter is really tough and keeps on flying. Though even if you do a thorough checkup and everything seems fine physically after a few crashes, there still may be issues with the calibration of the onboard IMU (Inertial Measurement Unit). DJI has a downloadable utility you can run (Windows only, bummer) that will run a diagnostic on your IMU and automatically calibrate it for you. Since I'm running Macs currently for all my video production, I wasn't able to try this yet, but will have to seek out a Windows machine sometime that will allow me to run this, as I can see mine is behaving badly – even after balancing props, etc.
Here is a video tutorial on YouTube by Colin Guinn, CEO of DJI Innovations North America
DJI also has a firmware upgrade for the Phantom, as well – but again, it's an EXE file so you're out of luck if you only have a Mac. But I do plan to get this update and calibration done soon though and will share my results soon…
Here is the link to the software downloads from DJI: http://www.dji-innovations.com/products/phantom/downloads/
**UPDATE: I was able to install Bootcamp on my MacBook Air with a minimal partition and installed Windows 7 and the NAZA-M Assistant software, DJI Driver and updated my Phantom firmware. Once calibrated, I was able to get a great response and control over my phantom again – as shown in this Slo-Mo shot I did of our horse last week:
I'm going to be experimenting with additional mounting options and definitely some ND filters to help control the rolling shutter and enhance the image quality of the GoPro. I'll also be doing more extensive side-by-side testing with different frame rates and resolutions with the Hero3 and will be sharing any updates and announcements from product manufacturers at NAB in April.
I wish to thank and acknowledge Don at DSLRPros.com for not only providing many of the parts and accessories for the DJI Phantom reviews, but also for his industry experience and knowledge. Since they are the US distributor of the DJI Phantom and other multirotor UAVs they would be the logical choice for learning more about them from their site.
I'd also like to thank Colin Guinn of DJI Innovations for sharing his experience and expertise with me. Look for their booth right across the aisle from GoPro at NAB this year!
Jeff Foster is a published author of several how-to books and training videos in the motion graphics, animation and video production industries and is an award-winning video producer and artist. Visit his web site to learn more about his training methods, tips & tricks at PixelPainter.com