Never use HV20 for onboard race car cam!

[Igor Babic]

I have done this last weekend for our documentary about race car driver. Picture was so shaken that is totaly unusable! Disabling Image stabilizer dosn't help much. It is not caused by mounting. It is nature of HV20 when is exposed to a big and loud noises and vibration. (I have seen this but on a smaller scale when I was filming live heavy metal band) Car is Smart ForFour prototype with 600HP engine. (and they use only 400HP for this race to keep car on the ground...) After first trial run we changed for standard DV elchipo Sony, and now we have something to show. This is just a quick note. Picture of mounting, car, race and video ASAP. HV20 is hardmounted with manfrotto clamp and manfrotto ball head. Tape is there just for extra protection. Video from HV20 was looking like heavy circular blured. Unusable...

[Axel Scheffler]

Finaly, I'm not the only one who has trouble with that and I can say, it's not only the HV20. I made the same sad experience with my HV10, too.
Is it maybe an effect that is coming with all cams that are having optical picture stabilizer? My good old Sony had an electronic stabilizer and never showed any shaking on my wind shield rig. For that reason I bought a Xacti 1010 which has an electronic stabilizer but had no chance to test it so far.

Regards

Axel

[Rich Sanchez]

It could be "rolling shutter" effect explained here: CMOS Rolling Shutter



Rich

[Bill Petropoulos]

From the photo it looks like the lens adapter and camera are picking up vibrations directly from the frame. They are in direct contact.

Maybe try to mount the camera with something between the camera and the roll bar to help isolate vibrations?

Imagine biting down on that roll bar with your mouth while the car is at full acceleration, I doubt your eyes would be of any use either.

Maybe a suction cup mount off the glass would be better. The rubber cup would help dissipate some vibration.



-Bill

[Tripp Woelfel]

Bill... You're not going to do better than the Manfrotto Superclamp. I've used them in race cars many times without any problems as long as the camera is not too heavy. The Panny GS 400 seems to be over that weight limit, but I'm not sure.

Leave image stabilization off. Think of the Superclamp as a very stable tripod. Set your cable up accordingly. Suction cup mounts will not be as stable. They can actually amplify the vibration. I know. I've tried those too.

In the final analysis it seems that rolling shutter is the problem. The linked description in Rich's post should help fill in the details. the only thing that might help you is a faster shutter speed. I don't know this for a fact but my guess is that if you scan one frame/field faster, the time delta between the first and last scan lines will be lower and the distortion will be less apparent. No way I know will eliminate it but that might help.

I also think that your lens adapter could be causing your problems by screwing up your center of gravity. In order to be effective, you'll have to anchor that with a separate clamp which could cause a whole different set of problems.

[Moayad Hassan]

Originally Posted by Tripp Woelfel

In the final analysis it seems that rolling shutter is the problem. The linked description in Rich's post should help fill in the details. the only thing that might help you is a faster shutter speed.

If it was a rolling shutter problem then a slower shutter speed would be the solution.. I think. For example, when using a vibration DOF adapter with the HV20 you can not use anything faster than 50 (PAL) other wise the image will wobble all over the place.

So a shutter speed of 50 or so might help.

[Tripp Woelfel]

Originally Posted by Moayad Hassan

If it was a rolling shutter problem then a slower shutter speed would be the solution.. I think.

Moayad... I could be assessing the rolling shutter situation backward but I don't think so. If I understand the rolling shutter phenomenon correctly, a faster shutter speed captures each frame faster. (That's me, Captain Obvious.) Logic indicates that should reduce the distortion not increase it.

I'm interested your theory as I could be totally wrong here with no empirical data to back me up.

If anyone has either experience or reference data on the effect of shutter speed on the rolling shutter effect, I'd be very interested.

[Igor Babic]

My camera was set to TV priority 50. So, it is not shutter.
If its rolling shutter, picture will be skewed on on side or something like this.
Picture looks like circular blur.
My guess that problem is optical image stabilizer system. Here is how it works.
http://www.dpreview.com/reviews/koni...es/asmovie.mov
Anti-shake: Optical: Glossary: Learn: Digital Photography Review.

[Chris Barcellos]

[QUOTE=Tripp Woelfel;942418]Moayad... I could be assessing the rolling shutter situation backward but I don't think so. If I understand the rolling shutter phenomenon correctly, a faster shutter speed captures each frame faster. (That's me, Captain Obvious.) Logic indicates that should reduce the distortion not increase it.

I'm interested your theory as I could be totally wrong here with no empirical data to back me up.

[QUOTE]

Tripp: I have to go with Moayad on this. My experience is based on my use of a self made vibrating adapter. I was having trouble with the adapter and getting a continuous Jello effect. I thought, like you, that speeding up shutter would help. I had been shooting everthing at 1/48 in Cinemode. So I upped the shutter speed as a test, and it got worse. When I ran shutter down to 1/24 sec, it virtually dissappeared.

Now I do know that the frequency of the vibration of the screen had something to do with it, but it still demonstrates the issues as they arise at higher shutters speed.

[Hubert Duijzer]

I've tried to mount a HV20 on a superclamp in my car and also on a 3-suctioncup mount.
It is totally unusable. It's a really horrible unfixable rolling shutter. There's only one solution for this, a good CCD-cam.
I don't like this fact, one of the reasons i bought this cam was for this kind of car inboard/outboard stuff.

[Michael Wisniewski]

I'm thinking if the el cheapo SD Sony cam worked, then it might be the HDV compression breaking down. Under the conditions you described, it sounds like a large part of the image would have had a lot of small, constantly changing details, which is usually where HDV starts to break.

[Igor Babic]

This is how it looks on my HV20. Two shots are in race. One is with car standing still, and last one is from elchipoDVcam. This is 2.5 min 5km uphill race with 2 trials and 2 runs. (thats how I have a chance to swap cameras, mounts and angles, and check for quality) We only need about 30-50 seconds of all takes together to make one part of the track for this documentary. wmv compression makes it look grainy, it actualy looks like round circles.
http://www.mediafire.com/file/xzgmoz...0racecam01.wmv
http://www.mediafire.com/file/quinqj...0racecam02.wmv
http://www.mediafire.com/file/gj5gty...0racecam03.wmv
http://www.mediafire.com/file/jmln5j...0racecam04.wmv

[Rick Hill]

Your results are in sync with my experience. I have a Sony HC3 which has EIS and I get great results when I mount it to vehicles (cars, boats). I also have an HV30 and I get the same "blur vision" like what your clips show.

My guess is the OIS elements themselves are being bounced around by the vibrations so that they actually _add_ bouncing to the image. The energy in the vibrations are greater than what the OIS elements can compensate for. They are designed for hand vibrations.

Canon could have added a way to at least secure the elements so that when OIS is not needed this cam could have been used in these types of applications. You wouldn't get image stabilization but you also would not get "extra" vibration either.

If you need a nice clean HD image, you may want to look into finding a Sony HC3 on Ebay or something. I am sure they are pretty cheap nowadays.

[Fred Turner]

Hey Everyone--

New to the forum here after I've had HORRIBLE results from my HV20. Hope y'all don't mind me dredging up an old thread! Funny thing that this thread was THE FIRST link when I Google searched "racecar on-board hdv cameras". Anyway, I'm getting the dreaded wobble in my C5 Corvette racecar:

http://homepage.mac.com/fredo/racin/...mera_Shake.mov

I called Canon, but the attitude-sporting phone jockey I talked to must've had a competition going to see how many times he could assure me that "Canon doesn't design that camera for mounting in a racecar". No sh*t. For a little bit there, he was gonna see if he could get me a way to talk to the engineers (which would've required calling Japan, of course), but naturally that didn't pan out.

Anyway, was just wondering if anyone had learned more, or gained more empirical data about HDV cameras and the CMOS Rolling Shutter Wobble ("CMOSRSW"? :D). I'd like to still have HD, but if this problem is inherent w/ all HDV consumer-level cameras, maybe going back to DV is best. But, Rick, you mention getting "great results" w/ your HC3...can you expound upon that? Any issues similar to wobble? Are the other Sony HCs getting good results as well? If so, I'll consider one of those. Otherwise, recommendations?

Thanks!
Fred

[Warren Kawamoto]

Originally Posted by Igor Babic

This is how it looks on my HV20.

That is definitely CMOS rolling shutter effect caused by high frequency vibration. No amount of mount dampening will improve it. The solution is to use a CCD camera.