More experiments with the GoPro HD Hero2

by Raymond Parker on June 18, 2012

in Cycling, Photography, Technical, Video

Img description

Bike Boom

Yesterday was a beautiful, if windy, day; perfect, I decided, for a spin along the waterfront to test out ideas for unusual on-bike camera angles.

During my first test of the GoPro Hero2 camera I determined a better solution, other than simply attaching camera to the seatpost, had to found for shots from the rear of the bike.

Bike boom

I’ve used the trusty Manfrotto monopod before (see video here), strapped to a rear rack for aft-end shots, so it was a no-brainer to try something similar for the camera-angle I had in mind. The resulting rig represents another kind of “bike boom.”

This time, using toe-straps and zip-ties, I lashed the monopod horizontally along the rear rack. An assortment of mounting brackets—including those that came with the GoPro Motorsports kit, and components of the accessory “Roll Bar Clamp”—attached camera to boom and allowed axis adjustments.

Camera settings & Accessories

One feature of the GoPro that came in handy is the “upside-down” photo/video mode. This allows you to mount the camera upside down (as illustrated above) while recording the images the “right” side up. In other words, there’s no need to flip the photo or video later on your computer.

The one frustration I have right now is the inability to know exactly what the camera’s field of view is recording. This is obvious from boom-mounted clips in the embedded video. It would be preferable not to see the boom, for instance. In wide (170°) mode, this becomes even more critical. I have a feeling I’ll soon be springing for the LCD BacPac™ accessory.

The Manfrotto “boom” also adds a good deal of “bounce factor” to the camera, so it’s not much good on bad pavement. The bike, my Marinoni Ciclo, is clad with 23C tires, inflated to around 90PSI.

I used the HD “Skeleton Backdoor,” allowing more audio transmission than the full waterproof housing.

Seaside ride

Once I’d overcome the impulse to press the menu button, instead of the on-off button, I recorded some video along the local Seaside Route, a favourite jaunt for recreational riders, training run for novice and professional cycle racers … and promenade for vintage car collectors and double-decker tour busses.

Conclusion

This was an interesting experiment. I need a way to monitor shots (LCD BacPac™) and improve stabilization (none added in post-processing). I’d consider all but a few seconds of the resulting “footage” unusable in a quality video production.

The embedded video is uploaded as full 1920X1080, recorded at 30fps. Optimize YouTube settings accordingly.

{ 9 comments… read them below or add your spin! }

Randobarf June 18, 2012 at 4:32 pm

I have made a few bike-mounted booms for bikes using aluminum square tubing, aircraft cable and water ballasts. I have found the only way to get any semblance of stability is with the water ballasts but they are incredibly dangerous! A Manfrotto Magic Arm works for some shots because it has a certain mass and it does not flex like a tripod, monopod or structural aluminum tubing. I have found the most useful HDHero shots to be from the chainstay facing forward, from the seatpost facing a drafting cyclist and from a Magic Arm on the handlebars pointing backwards at the face of the rider (also dangerous but the results look cool).

I think it’s important to maintain a steady horizon for following shots behind a cyclist. I have built a trailer-mounted, water-ballasted boom for that purpose. It’s very heavy and care must be taken not to ride like a maniac, flip the trailer over and smash the camera to smithereens.

One way to reduce vibration is to drastically lower tire pressure on big tires.

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Raymond Parker June 18, 2012 at 4:48 pm

Thanks for these tips. Sounds like some serious grip equipment! I’ve been trying to figure out how to incorporate a steadycam unit, but the usual design would likely spin in the wind. Maybe a built-in wind-vane ….

I’ve found 650bX42 to be the best “dolly” wheels.

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Randobarf June 18, 2012 at 5:09 pm

There is a lightweight gyroscopic steadycam made for mounting underneath a helicopter. However, every time you smash it up making your bike video it costs another $20,000 plus shipping and handling. Really I think it’s cheaper to purchase an assistant with the promise of fine ales. If they crash while riding with one hand you can always get another one for nothing. There’s also those videocam bike race guys who ride backwards on a motorcycle.

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Raymond Parker June 18, 2012 at 7:24 pm

I have a friend–ex-rando–with a Harley … likes Guinness.

Very much tempted to get a robocopter though.

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Randobarf June 18, 2012 at 8:03 pm

I think a robocopter would be awesome for cycling video. You can get robocopters that are powerful enough to haul a Canon 5D with a 24-70.

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Raymond Parker June 18, 2012 at 8:12 pm

I know. Some of the best overhead shots are being done with, for instance, the Octocopter. Would love to mount my D-7000 on one of those.

Can you imagine following a rando “peloton” from that perspective? Mini-TdF.

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Randobarf June 18, 2012 at 9:42 pm

Ray, thank-you for volunteering your D-7000! I am checking my credit card limit to see if I can get an Octocopter. I don’t yet know how to fly a helicopter but I am sure I can learn on the simulator DVD. What could go wrong?

The best helicopter footage of cycling that I have seen was in the IMAX Tour de France film, Wired to Win.

However, the aerial footage that most sticks in my mind was a chopper shot from the film about marathon cycling, Bicycle Dreams.

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Stephen Hinde June 28, 2012 at 10:04 pm

It’s been a while since my engineering days, so I can’t do the calculations any more, nor do I have the fancy programs used today. But, a few ideas on vibration damping for the boom.

Two analogies to consider. First, the tightrope walker who controls balance through the use of a long pole. Second, the cyclist with the elastomer seat post (like a ThudBuster).

In the first case, sideways movement (vibration) is controlled through the use of weight and lever length to change the speed of vibration so that the walker can modify the stance to prevent inadvertent movement. In the second case, the weight of the rider preloads the elastomer, which is really just a flexible material that resists movement, and the combination of the weight and the flexibility of the material adsorbs the vibration.

Traditional vibration dampers often use air. Air is a compressible fluid, and will change volume when compressed. By adjusting the amount of air and the pressure, you can modify the damping for the speed of vibration and the force (related to the weight) that it must resist. Air shocks are generally fairly stiff containers that slide into each other as the inner gas compresses (giving a lower volume of air but at higher pressure). Water can be used as the fluid, but as water is fairly incompressible, the water itself is actually a weight (that must move) and it is the container that is flexible (think of a water balloon–the rubber stretches but the volume of water doesn’t change).

To apply all this to your problem. The boom you are using (Manfrotto monopod) is a stiff pole that transmits vibration well. Also, the length of the boom (how far away from the centre of the bike) magnifies the movement (Archimedes at work!). I suggest that you use high-density foam (HDF) blocks under the boom, attached at 2 locations–one as far back on the rack as you can go (to minimize the overhang distance) and one as close to the seat post as possible. At this second location, you may also want to place HDF on top of the boom to restrain upward motion. Add weight on top of the boom between the HDF blocks to provide some preloading (and inertial damping). A small weight added to the end of the boom above the camera might also help in reducing vibration. The latter is similar to the damping mechanisms used on tall chimneys to prevent wind sway–just turned sideways.

Of course, your best solution is to prevent the vibration in the first place–high volume tires at low pressure. Not only will the tires then adsorb the vibration, but the increased road friction and squirrelyness (good engineering word!) will slow you down so that the vibration is less violent.

Have fun playing around.

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Raymond Parker July 1, 2012 at 11:17 am

Thanks Stephen. I’m definitely going to get some closed-cell foam and try out your DIY stabilizing tips!

As I’ve noted before, 650B is the way to go for the best road damping.

Of all my on-bike videos, the one on the main “Commuting” page is best as far as stabilization (though not HD). It was made with camera on front rack of the Bleriot.

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