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Image/Lense Vibration


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#1 Chris Banting SOC

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Posted 26 September 2006 - 12:34 AM

I have been experiencing lense vibration on the longer end of the HD short zoom (24mm) while flying the Sony 900 camera. We even swithced all shots to primes today and it worked great untill the director wanted a 28mm (equivilent to about 65mm). We have tightened every possible screw and anything else that you could imagine to illiminate movement and vibration. There is a tiny bit of play in my fore/aft adjustment though. Perhaps this could be the problem. Does anyone have any advice? Service tips? Perhaps it is time for the Donkey Box III.

Pro II sled
XCS Gimbal.
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#2 Bruce Alan Greene

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Posted 26 September 2006 - 12:52 AM

I have been experiencing lense vibration on the longer end of the HD short zoom (24mm) while flying the Sony 900 camera. We even swithced all shots to primes today and it worked great untill the director wanted a 28mm (equivilent to about 65mm). We have tightened every possible screw and anything else that you could imagine to illiminate movement and vibration. There is a tiny bit of play in my fore/aft adjustment though. Perhaps this could be the problem. Does anyone have any advice? Service tips? Perhaps it is time for the Donkey Box III.

Pro II sled
XCS Gimbal.


Chris,

I'm using the original PRO donkey box on my home-made sled. I did a lot of testing when building my sled to reduce this problem and I found the biggest contributor towards this shake is post length and resonance. I found the telescoping PRO post to be very problematic and my new sled now has a carbon fiber non-telescoping post. This has mostly eliminated this effect, but if I slide my batteries to the right position on my post I can induce harmonics that will find their way to the image (so I try to avoid that).

I have also learned that a well cushioned shoe can make a very large improvement as well. Ultimately, all vibration begins in the foot and travels up the bones and into the sled.

Unless your donkey box is very out of adjustment, I would look at the center post first to reduce the vibration. Keep it as short as possible as a rule of thumb.

Also the f-900 is a very long camera with a high center of gravity. Make sure it is screwed down securely as well.

Hope this helps some. I found that each time I eliminated some vibration, it would show up in another place. Even a very stiff sled will resonate at some frequency.
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#3 Alec Jarnagin SOC

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Posted 26 September 2006 - 03:33 AM

Chris,

Which camera plate are you using? The Sony quick release plate can add lots of vibration to an image. It varies from plate to plate - check this.

Also, the DB2 has tiny set screws that directly influence this too (you'll see rows of them along the back and side of the DB2 - they should apply even pressure on their respective pressure plates - not so much that it becomes difficult to adjust the trim knobs, but enough that the camera does not vibrate).

Cheers,
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#4 stcm

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Posted 26 September 2006 - 07:26 PM

The Sony Plate is the biggest problem. Ask for a Chrosziel camera plate. They hold the camera rigid. Also Plus 8 has a good camera plate system.
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#5 AdamKeith

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Posted 26 September 2006 - 07:44 PM

Try raising the back pin on the Sony plate. It should help with any vibration

Regards,
Adam Keith
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