Stabilization w/ A1? at DVinfo.net

Tim Ribich · November 16th, 2006, 09:18 PM

We shot some video this summer out an open door in a small plane using an Canon Optura XI. Footage came out decent, but suffered from "high frequency" (?) vibration. Obviously the stabilizer could not compensate for the vibrations in spite of my best efforts (hand held & not touching any part of the plane e.g.).

Would there be any reason to expect that a similar session with the AI produce any better results?

Chris Hurd · November 16th, 2006, 09:59 PM

Not so sure about that -- the OIS mechanism is the same type (lens shift) in both cams. Your best bet is to rent and try (and please report your findings).

Tom Roper · November 17th, 2006, 12:09 AM

The A1 OIS effectively quells the high frequency vibration, very specifically.

My Linkplayer2 that I use for HDV playback occasionally freezes, and there is a "pause/play" trick on the remote that gets it started again.

But some of my A1 handheld shots are so steady I'm the one tricked into thinking the video is frozen, when it's not. Handheld can look like it was shot with a tripod with this cam if I do my part. No kidding!

Chuck Spaulding · November 17th, 2006, 01:50 AM

generally speaking high frequency vibrations are caused by either the tail rotor if its a helicopter or the prop is its a small fixed wing being out of balance.

If there's a hi-freq vibration in a helicopter the pilots feet will go to sleep in a matter of minutes, in a fixed wing your butt goes numb. Either way you don't really feel it but it can cause the camera to be ever so slightly out of focus.

If this happens, and depending on the type of plane, the pilot can adjust the pitch of the prop (pull the prop back) and slow the RPM from 2500 to less than 2000 RPM this will slow the plane a bit but it might really smooth things out.

Tim Ribich · November 18th, 2006, 11:20 AM

Quote:

Originally Posted by Chris Hurd

Not so sure about that -- the OIS mechanism is the same type (lens shift) in both cams.

Interesting.

Awhile back I asked the KenLab folks about their gyro system thinking that might help. Their reply was that it would help with the overall motion, but the vibration would be another matter. I obviously have some things to learn about how this stuff works (I had sent them a pic of a camera mounted on a rather inexpensive pan/tilt system mounted on an airplane wing we were using at the time)

Quote:

Originally Posted by KenyonLabs

One thing you will need to address ( unless you already have- hard to tell in the pic), the rig must be isolated from the plane by some sort of vibration reduction mount- Lord Mounts, Unisorb- some thing that will remove the metal to metal conduction of the engine vibration to the camera / gyro- pan tilt apparatus- this will allow the gyro to keep on the desired target and the camera free of this unwanted vibration. Even rubber sleves

I've done aerial photography for many years, but only testing the video for the past couple of years so a huge investment in one of higher end aerial system is not a viable option for now.

But KenyonLabs response has me wondering where something even as simple as setting the camera on a dampening cushion of some kind (beanbag? foam?) might show some improvement when shooting handheld.

Wont be flying for another couple of weeks so I've some time to entertain any suggestions in the meantime. <g>

Chuck Spaulding · November 18th, 2006, 01:42 PM

When shooting stills from a plane most of the time your shutter speed is fast enough to filter out the vibration. You also should differentiate between vibration that can effect the performance of your camera versus movement of the aircraft that challenges your ability to get a steady shot.

The gyro system from Kenyonlabs is great at stabalizing shots but can do nothing about vibration. In airplanes and helicopters there are parts that have enough mass that if they are out of balance will cause the aircraft to "shake," kind of like a tire that's not balanced correctly on a car. But on an aircraft they are traveling at a much faster speed, so much so that you can't really feel it but the camera will pick it up. It often makes your footage appear to be out of focus.

There's not a lot you can do to isolate your camera from the high-frequencies in an aircraft, here's a few suggestions:

Don't mount the camera to anythig rigid. That's why kenyanlabs suggested using a bean bag. Usually the seats are well insulated from vibration, if you have the room place the camera support of your legs.

Choose an airplane that has at least a three bladed adjustable propellor or if using a helicopter a fully articulated three bladed main rotor.

Turbine engines are always better than piston engines, a lot fewer moving parts and much smoother. Unfortunately, most small airplanes will be piston.

Also, tell the pilot to slow down, find an altitude with a little less turbulence or both. Depending on what your trying to photograph you might be able to start at a higher altitude, pull the throttle all the way back, feather the prop and glide. It will get significantly smoother.

Tim Ribich · November 21st, 2006, 12:25 PM

Hi Chuck,

Quote:

Originally Posted by Chuck Spaulding

The gyro system from Kenyonlabs is great at stabalizing shots but can do nothing about vibration. In airplanes and helicopters there are parts that have enough mass that if they are out of balance will cause the aircraft to "shake," kind of like a tire that's not balanced correctly on a car. But on an aircraft they are traveling at a much faster speed, so much so that you can't really feel it but the camera will pick it up. It often makes your footage appear to be out of focus.

When I get a chance, perhaps I'll post some video to show what I'm seeing-- pretty much as you describe it.

Quote:

Originally Posted by Chuck Spaulding

Choose an airplane that has at least a three bladed adjustable propellor or if using a helicopter a fully articulated three bladed main rotor.

Turbine engines are always better than piston engines, a lot fewer moving parts and much smoother. Unfortunately, most small airplanes will be piston.

Good advice-- thanks. At this point the video part of our aerial efforts are pretty in early beta. <g> While we do have access to helicopters, as you know they're very expensive. Main platform are different 172s around the state that we hire.

Actually my preference for low-level personal shoots lately has been fixed wing ultralights. We can cruise at +/- 100 MPH yet do low/slow when over target. Of course there the problem are that we have to be cognizant of the commercial conflicts in using that class of aircraft.

Thanks again for the input.

Noel Evans · November 22nd, 2006, 09:12 AM

Great post chuck very informative. The other option is operator isolation via a steadicam.

Chuck Spaulding · November 22nd, 2006, 11:02 AM

Quote:

Originally Posted by Noel Evans

Great post chuck very informative. The other option is operator isolation via a steadicam.

Depending on the aircraft that is certainly an option, but in an airplane as small as a 172 there probably isn't enough room.

I have shot out of the tail of a B25 and removed the cargo door from a V-tail Bonanza and laid on the floor. In both cases I just used a sand bag to isolate the camera which worked great. Of coarse technically the latter was illigal...

Jay Fisk · November 22nd, 2006, 01:08 PM

If using a tripod it absolutely must be isolated from the plane . Multiple layers of different density foam, from egg crate soft stuff to the blue ensolite type found at REI stacked up in those 12x12x4" Rubbermaid type food containers works well. Cut a hole in each lid for the tripod leg. Put the highest density on top or use a disc spreader with a recess or hole for your tripod tips. Use lots of lightweight bungee cord to floor attachment points to preload the foam packs.

If you can't shoot out a door or wild (missing) window you'll want to make an adaptor plate to place the nodal point of your tripod under the front lens and place the head as close to the window as possible to allow pan & tilt within the window frame. Ask your pilot to make sure the window is clean. They have some amazing stuff for plastic.

If you're rigged correctly and use a remote controller it's possible to get really stable shots at 14-18x zooms with single-engine turbine powered planes (Cessna 208 Caravans or a Pilatus PC-12 if you've got the budget) Twins are ok but almost always have an engine sync harmonic every few seconds. Keep your hands off the camera and use a bungee cord to make any moves. Better to work with your pilot and have them make any moves. Get a headset too.

It will be interesting to see what Canon's stabilization does for handheld shots. I'm sure it softens teh pan & tilt component, doubt if it does the roll axis but neither does a Kenyon unless you use two of them.

A1.... soon!

November 16th, 2006, 09:18 PM	#1
Tim Ribich Regular Crew Join Date: Mar 2005 Location: Upstate NY, USA Posts: 138	Stabilization w/ A1? We shot some video this summer out an open door in a small plane using an Canon Optura XI. Footage came out decent, but suffered from "high frequency" (?) vibration. Obviously the stabilizer could not compensate for the vibrations in spite of my best efforts (hand held & not touching any part of the plane e.g.). Would there be any reason to expect that a similar session with the AI produce any better results?

November 16th, 2006, 09:59 PM	#2
Chris Hurd Obstreperous Rex Join Date: Jan 2001 Location: San Marcos, TX Posts: 27,368 Images: 513	Not so sure about that -- the OIS mechanism is the same type (lens shift) in both cams. Your best bet is to rent and try (and please report your findings). __________________ CH Search DV Info Net \| 20 years of DVi \| ...Tuesday is Soylent Green Day!

November 17th, 2006, 12:09 AM	#3
Tom Roper Trustee Join Date: Jun 2004 Location: Denver, Colorado Posts: 1,891	The A1 OIS effectively quells the high frequency vibration, very specifically. My Linkplayer2 that I use for HDV playback occasionally freezes, and there is a "pause/play" trick on the remote that gets it started again. But some of my A1 handheld shots are so steady I'm the one tricked into thinking the video is frozen, when it's not. Handheld can look like it was shot with a tripod with this cam if I do my part. No kidding!

November 17th, 2006, 01:50 AM	#4
Chuck Spaulding Trustee Join Date: Nov 2004 Location: Thousand Oaks Posts: 1,104	generally speaking high frequency vibrations are caused by either the tail rotor if its a helicopter or the prop is its a small fixed wing being out of balance. If there's a hi-freq vibration in a helicopter the pilots feet will go to sleep in a matter of minutes, in a fixed wing your butt goes numb. Either way you don't really feel it but it can cause the camera to be ever so slightly out of focus. If this happens, and depending on the type of plane, the pilot can adjust the pitch of the prop (pull the prop back) and slow the RPM from 2500 to less than 2000 RPM this will slow the plane a bit but it might really smooth things out.

November 18th, 2006, 01:42 PM	#6
Chuck Spaulding Trustee Join Date: Nov 2004 Location: Thousand Oaks Posts: 1,104	When shooting stills from a plane most of the time your shutter speed is fast enough to filter out the vibration. You also should differentiate between vibration that can effect the performance of your camera versus movement of the aircraft that challenges your ability to get a steady shot. The gyro system from Kenyonlabs is great at stabalizing shots but can do nothing about vibration. In airplanes and helicopters there are parts that have enough mass that if they are out of balance will cause the aircraft to "shake," kind of like a tire that's not balanced correctly on a car. But on an aircraft they are traveling at a much faster speed, so much so that you can't really feel it but the camera will pick it up. It often makes your footage appear to be out of focus. There's not a lot you can do to isolate your camera from the high-frequencies in an aircraft, here's a few suggestions: Don't mount the camera to anythig rigid. That's why kenyanlabs suggested using a bean bag. Usually the seats are well insulated from vibration, if you have the room place the camera support of your legs. Choose an airplane that has at least a three bladed adjustable propellor or if using a helicopter a fully articulated three bladed main rotor. Turbine engines are always better than piston engines, a lot fewer moving parts and much smoother. Unfortunately, most small airplanes will be piston. Also, tell the pilot to slow down, find an altitude with a little less turbulence or both. Depending on what your trying to photograph you might be able to start at a higher altitude, pull the throttle all the way back, feather the prop and glide. It will get significantly smoother.

November 22nd, 2006, 09:12 AM	#8
Noel Evans Regular Crew Join Date: Feb 2006 Location: Tokyo, Japan Posts: 157	Great post chuck very informative. The other option is operator isolation via a steadicam.

November 22nd, 2006, 01:08 PM	#10
Jay Fisk Regular Crew Join Date: Oct 2006 Location: CSL BCS MX Posts: 67	If using a tripod it absolutely must be isolated from the plane . Multiple layers of different density foam, from egg crate soft stuff to the blue ensolite type found at REI stacked up in those 12x12x4" Rubbermaid type food containers works well. Cut a hole in each lid for the tripod leg. Put the highest density on top or use a disc spreader with a recess or hole for your tripod tips. Use lots of lightweight bungee cord to floor attachment points to preload the foam packs. If you can't shoot out a door or wild (missing) window you'll want to make an adaptor plate to place the nodal point of your tripod under the front lens and place the head as close to the window as possible to allow pan & tilt within the window frame. Ask your pilot to make sure the window is clean. They have some amazing stuff for plastic. If you're rigged correctly and use a remote controller it's possible to get really stable shots at 14-18x zooms with single-engine turbine powered planes (Cessna 208 Caravans or a Pilatus PC-12 if you've got the budget) Twins are ok but almost always have an engine sync harmonic every few seconds. Keep your hands off the camera and use a bungee cord to make any moves. Better to work with your pilot and have them make any moves. Get a headset too. It will be interesting to see what Canon's stabilization does for handheld shots. I'm sure it softens teh pan & tilt component, doubt if it does the roll axis but neither does a Kenyon unless you use two of them. A1.... soon!