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Testing: Mobius Action Cam for RC Plane Video

By Terry Dunn

As good as GoPro Hero cameras are, there are times when they are too big, too heavy, or too expensive for the job. There is a new sports camera on the market that may bridge that gap for many users: the Mobius Action Cam.

As good as GoPro Hero cameras are, there are times when they are too big, too heavy, or too expensive for the job. Smaller, lighter, and cheaper alternatives such as key fob cameras have been available for a while now. The problem is that these types of cameras rarely provide image quality even close to what the latest Heros can crank out. There is a new sports camera on the market that may bridge that gap for many users: the Mobius Action Cam.

The Mobius Action Cam is a small sports camera that fills a void between key fob cameras and the GoPro lineup.

Personally, I use sports cameras on many of my RC airplanes. Several of my smaller park flyer models weigh less than a pound and they simply can’t schlep my Hero 3 Black camera (5.6 ounces with the housing, 2.6 ounces naked) into the sky. I’ve tried a key fob (ie. spy) camera on these airplanes, but I was never happy with the results. I was tempted to try the Mobius in this application for three primary reasons: it is slightly smaller than the GoPro, it weighs about half as much (1.4 ounce), and its video capabilities are quite similar to my older Hero 2 (which I’m still happy with). The clincher was that the Mobius sells for around $80.

Here you can see the relative size difference between a GoPro Hero3 Black, Mobius Wide Angle, Mobius Standard Lens, and a generic key fob camera.

Here's how the Mobius performed after testing it on my RC planes, including some sample videos to compare it to the GoPro Hero 3.

Mobius Breakdown

The Mobius is available in two versions; standard lens and wide angle. I’ve been using the standard version for about a month, and I just recently purchased a wide angle version as well. The housing measures 2.4”(l)x1.4”(w)x.7”(h). In actuality, this is not much different from the Hero 3 Black. What I find particularly useful for my purposes is the form factor. The lens is located on the smallest side of the camera, making it more aerodynamic. That may seem silly to those of you who strap cameras to your surfboard or handlebars, but it can make a big difference with little airplanes.

The basic Mobius package includes the camera as well as two mounting methods.

There are three buttons used to operate the Mobius; Power, Function and Shutter. The two silver areas that look like buttons are actually heatsinks. The function of the power button is obvious. It is worth noting that there is a “power on delay” option. This helps prevent inadvertent start-ups while the Mobius is in your pocket. Think of it as the sports camera solution to butt dialing.

The function button toggles between three recording modes that you define with the interface software. Each time you turn on the Mobius, it defaults to the Video 1 mode. Simply press the function button to enter Video 2 or Photo mode. There is no screen of any type on this camera. Menu feedback is provided through a multi-color LED. Each mode spawns a different color (orange, blue, and red respectively).

The Shutter button initiates recording in whatever mode you are in. Push it once to start, and again to stop. If you are set up to shoot single photos (as opposed to time lapse), you get a photo each time you press the button. Simple stuff.

Data is stored on a micro-SD card (not included). You can use cards up to 32MB. Strangely, Class 4 cards are recommended, rather than faster types. They even advise against using faster cards. This will save you a few bucks, or provide a new home to an older card. Next to the card slot is a mini USB port used for downloading images and interfacing with the control software. The USB port is also used to charge the internal LiPo battery (which is not removable). I’ve never run mine completely down, but you can expect about 90 minutes of record time on a fully charged battery.

Recording Specifications

A time lapse option allows you to choose photo intervals ranging from .25 second up to a minute.

The Mobius can record video at either 720p (1280x720 pixels and 30 or 60 frames per second) or 1080P (1920x1080 pixels at 30 fps). In the 1080p mode, you can select wide (116-degrees on the wide angle lens, 85-degrees on the standard lens) or normal field of view (63-degrees on the wide angle lens, 46-degrees on the standard lens). The 720p mode is limited to the normal field of view at 60P and wide field of view at 30P.

When taking still photos, you can select either of the resolutions noted above or an even larger 2304x1536 pixel setting. The time lapse option allows you to choose photo intervals ranging from .25 second up to a minute. I typically choose the 5 second option for my flights.

Movies are saved as .MOV files and photos are .JPG. The Mobius also claims to have CD-quality sound recording. I can’t really say I exercise that very much since most of my recordings consist of whirring electric motors and wind noise that I soften or mute completely in post production.

Interface Software

Setup of the Mobius is performed via a free interface program that is available for PC and Macs. In addition to setting up parameters for the different camera modes (video 1, video 2, photo), there are tons of other adjustments that can be made. For instance, you can set up the Mobius to start recording via a built-in motion detector with variable sensitivity.

A computer-based GUI allows Mobius owners to adjust numerous parameters of the camera and perform basic housekeeping such as formatting the memory card.

One of the program menus allows you to make adjustments to image attributes such as contrast, exposure, and white balance. If you know that you will be recording in predictable lighting conditions, these can be very handy adjustments to optimize the image quality. Since the outdoor conditions that I typically operate in can vary widely and quickly, I leave all of these settings in normal/automatic mode.

The Mobius GUI has a Tools menu that can check-for and install new firmware on the camera. The same is true regarding updates to the GUI itself. This menu also lets you format the micro SD card without removing it from the camera.

Mounting Options

I purchased both of my Mobius cameras as a basic package from Ready Made RC. In this package, you get the camera itself, some self-adhesive Velcro, and a plastic cradle with a ¼-20 female threaded insert (to mate with most tripods). I see that other vendors offer the Mobius along with a selection of other mounts for different applications. As the Mobius continues to gain popularity, the mount selection will only broaden.

Simple Velcro keeps the Mobius attached to this airplane at more than 100 mph.

I have found that the two simple mounting devices included with my camera are extremely versatile. The usefulness of Velcro is self-evident. What could be more adaptable than this stuff? I’ve even used the Velcro to mount the Mobius on a molded fiberglass airplane that reaches upwards of 130mph in flight. I only pull positive Gs during these flights, but the forces trying to rip the camera free are substantial. The Mobius hasn’t fallen off yet! The only thing I don’t like about the Velcro is that it interferes with the fit of the plastic cradle. So I have to add or remove Velcro each time I swap mounting methods.

I use the cradle often as well. It is perfect when I want to elevate the camera above the airframe a little, I just run a ¼-20 nylon thumb screw from inside the airplane through the outer wall (usually made of foam). I make a simple foam spacer to get the height that I want and sandwich it between the airframe and the cradle. These setups usually allow me to rotate the cradle so I can try different camera angles.

Using the cradle mount and a nylon thumb screw, the Mobius is adaptable to small RC models such as this foam WW2 fighter.

Now that I have been using GoPro cameras for a few years, I have several airplanes and video rigs that are set up with the self-adhesive mount bases that are included with GoPros. I wanted to find a way to attach the Mobius to use these same mounts. The adapter I came up with is pretty simple. I took the short arm from a GoPro 3-Way Pivot Arm set and reamed out the end with 3-flanges (the end that interfaces with the camera housing) with a ¼” drill bit chucked into a hand vise. Next I took another of those ¼-20 nylon thumb screws (I use them a lot) and ran it through the fresh hole. I cut the bolt to have about 3/16” of thread protruding and then screwed the cradle onto it. Now I can mount the Mobius to a GoPro Vertical Quick Release Buckle and snap it into any of the well-used mounts. This adapter also lets me hook the Mobius directly to the built-in mount on the belly of my DJI Phantom.

The adapter also allows me to attach the Mobius directly to my DJI Phantom quad-rotor.

Using the Mobius

There isn’t much to say here. You just select the mode you want and press the shutter button. I was concerned that the LED indicator would be hard to see in bright sunlight, but that hasn’t been the case. Like all small cameras, this one is susceptible to “rolling shutter” distortion if it is exposed to vibration during use. It doesn’t seem any more or less sensitive to this issue than any of my GoPros. The solution is to get rid of the vibration (balance those props) and/or do your best to isolate the camera from the trouble source.

This still photo taken with a standard lens Mobius gives you an idea of the image quality that is possible with this camera.

So far, I have been pleased with the image quality I get from the Mobius. I do most of my filming at 720P/60fps and that seems to work well given the speed that most of my models travel. I play with 1080P from time to time and also shoot still photos on occasion. I am lingering on the fence regarding my preference of the standard or wide angle lens. The standard lens tends to provide more detail and less of an abstract, removed feel. Footage from the wide angle lens tends to be more dramatic. You get a lot of scenery and a reasonable level of fish-eye distortion. I think the key will be determining the strongpoints of each lens type and using that knowledge to select the right one for each application. That will come with more usage of these cameras.

This shot was taken using a Mobius Wide Angle while flying inverted over a cotton field on a cloudy day. I think it has an interesting mixture of patterns. Note the vignetting in the corners.

I have noticed that still photos taken with the wide angle lens in the highest resolution setting have vignetting in the corners. That is a common by-product of wide angle lenses. So I just consider it the cost of doing wide-angle business.

Conclusion

I realize that I’ve mentioned GoPro cameras in this article nearly as much as the Mobius. I’ve done so simply because their popularity makes them a handy reference point. However, I think it is important to avoid direct comparisons between the two brands. They are not really peers in this market. Yes, they have similar intended uses, but I don’t think there is any argument that the latest Hero model is the better camera. Yet as I write this, a Mobius is one-fifth the price of a Hero3 Black+. Make no mistake; the Hero3 is not five times better than the Mobius…not even close. So if you insist on comparisons, give Mobius a win in the “bang for the buck” column.

For those of you not quite ready to strap a $400 dollar camera to your helmet, fender, or toy airplane, the Mobius offers a more affordable alternative with comparable image quality. The camera’s smaller size and weight give it the advantage of being the only practical choice in some applications. I will continue to use my GoPros whenever doing so is prudent. At the same time, I am excited to continue to explore the new opportunities that are afforded by the size and weight of the Mobius.