All about GYRO's
Posted 14 January 2004 - 01:08 PM
Posted 15 January 2004 - 05:37 AM
I wouldn't knock GPI's design that fast, they were the first to offer Gyros modified and build in series to work on a Steadicam and make it widely available. I don't believe you can get anything from Tiffen (please advice...). Even though Garrett was the first to use them back on Star Wars 3 (or 6? Whatever).
Not as knowleadgeable about Gyros as Larry, but for what it's worth:
Usually GPI does retro-fits to Kenyon Gyros not purchased from GPI directly (GPI: 818-982-3991), at least they did to mine. It's just way more cost effective to buy the Gyros (if you buy new) from GPI. The Kenyon KS-6 (last time I checked) from the factory where $2400.- a piece. The retro-fit was in the region of ~$400.- a piece... that makes $2800.- versus $2100.- (including the retrofit) directly from GPI...
For the $400.- you get a little junction box with two 2 pin Lemo connectors (you can Daisy-chain 2 Gyros from one Plug and you cut down on cables) you loose the curly cable from Kenyon, also you get the PRO mounting clamp. This will only mate with the PRO Gyro Spuds.
Brackets available from GPI are: The AB Gyro Mount (with a 45 degree spud, the 90 degree spud is no longer available), Camera Plate Gyro Mount and the Post Clamp Gyro Mount. (The PRO 2 Battery Rack Gyro Mount is no longer available).
All of the brackets and all of the Gyro AKS are available separately...
The other manufacturer that makes brackets and AKS for Gyros as well as Gyro retrofits, would be XCS: 805-531-0014 (Greg Bubb). He does his own retrofit to the Gyros (check his website) and has a similar Clamp/Spud system (AB, Camera Plate, Center Post). The difference is that you can order a one off bracket that he will make up to your specs. Once he made a couple of spuds with the famous, what was it... 45 degrees... 47 1/2 degrees after the operator had talked to Larry... (His mounts are a little to bulky for my taste at least compared to the GPI stuff).
All of the PRO Brackets fit my Ultimate, exempt for the Post Clamp of course because it's 2", Greg made me a custom one, consisting of a Monitor Clamp and a custom Gyro Spud to fit my Gyros. (See pix at bottom).
(BTW: I'm using the Kenyon Inverter, can't beat it in sice and at a price of $300.-)
I believe MK-V makes some kind of Brackets, but I'm not familiar with them at all...
All of course depending what kind of mounts you already have on the Gyros and how much money you want to spend...
Hope that helped.
Posted 15 January 2004 - 05:51 AM
In your two pictures you've got one setup with both gyros on the post and the second with one on the camera and one on the post. What are the merits of both setups?
Posted 15 January 2004 - 10:28 PM
Posted 12 May 2004 - 07:25 PM
Posted 13 May 2004 - 12:31 AM
At the end of the day though, I still opted for Kenyon units (http://www.ken-lab.com/), They are the tried and true. Well crafted; solid buggers. The word on the Israeli ones are that they just aren't built as well. Also, for me, it is nice to have the manufacturer in the next state over (they are made in Connecticut).
Posted 05 July 2004 - 04:23 AM
"The more leverage the gyros have (length of post to gimbal) the more effective the stabilisation."
Has anyone out there got the definitive answer as to whether this is true or not?
The thing I can't get my head around is that if distance is a factor, then reducing the gymbal/gyro distance to zero (ie. imagine a gimbal with the gyros mounted inside) would make the gyro effect zero. This doesn't sound right because the gyros work fine when you hold them in your hands and try to rotate them about their own axis.
Posted 05 July 2004 - 04:53 AM
How are you?
The way this works is that the more leverage you have the stronger the effect.
It is like the antlers - the further out they go the more stable it is.
All I know is with all the tests we have done by mounting the gyros as far as possible from the pivot (Gimbal) the better the 'lock'
if you mount to the base far away from the gimbal and the gyro has 5% of movement - then is taken up by the post length (so by the time the movement gets up there you would not see it). If you are on the pivot and the gyro allows 5% of movement - then by the time it gets down to the base it is swinging away.
As you said if you have them in your hand - if you hold them out and pan your body you can feel the effect - but if you were to mount it to your body you would not get any where near the same effect.
I hope this makes sense.
If you would like to come and fly the AR please let me know.
Hope to see you soon
All the best
Howard J Smith MK-V
Posted 05 July 2004 - 06:08 AM
Nice to hear from you. Thanks, would love to try out the AR. Things are a little chaotic for a week or so but if it?s OK I?ll call you after that and see if you're around and a demo is possible.
As far as the gyro question goes......do you think that the extra 'lock' you've experienced with the gyro further from the gimbal could be due to an antler type effect ie. the weight alone of the gyro (without having to spin) giving you the extra stability? This would make sense, as the weight of gyros is pretty significant and placing that weight at such a distance from the gimbal will act as an antler does. I suppose what I?m saying then is that the gyro actually has two effects;
1. Its dead weight effect which works in roll and tilt and not pan (if gyro mounted over the post).
2. The gyroscopic effect which is independent of gyro to gimbal distance, because the gyro effect acts as a force resisting angular movement only.
Posted 05 July 2004 - 10:45 AM
You are absolutely right, there is no difference whatsoever in the rotational inertial resistance that the gyro effect exerts in various mounting positions on the steadicam. You do get the extra effect of more "dead weight" inertia by mounting them far from the gimbal as with any weight mounted away from the gimbal. One of the things I like about gyros is they allow more rotational inertial stability without expanding the overall footprint of the sled as expanding elements of the sled or adding the antlers do, and also that this extra rotational inertia goes away as soon as you rotate (pan, tilt, roll) faster than about 30 degrees/sec (depending upon the angles the gyros are mounted relative to these axes) as the internal rotors bump up against their limits. By keeping the gyros mounted close to the gimbal you can achieve high rotational inertia when making slow moves and magically have it go away for whip pans. On the other hand, by mounting them far from the gimbal you get more overall inertial stability, so you get more when rotating the rig slowly, but you also have more inertia after the rotors cage so you can't do whips as easily. So there are different ways to use them.
But getting back to the original question, the gyro effect has nothing to do with where they are mounted. Imagine holding them outstretched in your hand again. If you translate them in space without any rotation (tracking side to side for instance) they offer no gyro effect whatsoever. Try to rotate them, however, and they resist mightily. The extra translation in space that occurs when they are mounted away from the gimbal (they travel in an arc rather than just rotating on a point) does no produce any gyro effect - it is only the rotation itself that matters, and that rotation is exactly the same no matter how far they are from the center of rotation. It is an angular resistance only - that is the key for understanding how they work, what the gyro effect is. The weight of the gyros offers extra inertia for all accerations, including translations in space without rotation, but the gyro effect has only to do with the rotations. We should remember that the most important isolation that a steadicam offers is angular. We can move the sled around our body smoothly because of the arm helps to filter out translations in space, but it is the angular isolation that matters the most in making shots look smooth. This is why the gyros work so well in demanding situations like fighting gusty winds and with vehicle mounts.
Other considerations do come into play however. The gyros should have as rigid an attachment as possible to the camera so you won't get undesirable oscillations and vibrations. A too flexible post with loose fitting connections between the gyros and the camera will make these problems much more apparent. This argues for mounting them to the camera itself, or at the very least the post. But overall CG considerations, including maintaining dynamic balance and avoiding interference with your body and view of the monitor restricts mounting positions pretty seriously
Posted 05 July 2004 - 11:15 AM
(how are you?)
Thank you very much for clearing this up - for both of us.
What I was saying (not as well as you) was that I found the effect of the gyros worked better for me on the base of the MK-V - but this is also down to the additional bottom mass - I was able to track on a 300mm with ease.
All the best
Posted 05 July 2004 - 11:32 PM
This is fresh in my mind because I am just revisiting the whole use of gyros thing. Built a new test bracket that allows any orientation of up to 3 and I am shooting a video to demonstrate the various configurations and their plusses and minuses. I hope to be able to clear up a lot of the confusion and mystery of these things.
Posted 05 July 2004 - 11:48 PM
That's extremely interesting Larry, do you think there will be an easy way for us all to see this video?
I am shooting a video to demonstrate the various configurations and their plusses and minuses.
Maybe put it online or something?
There is still an awful lot of voodoo involved with gyros I think, might be good to see a side by side!
I know I'd watch!
Peace, Ruben "Waiting for the theatrical release" Sluijter