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Old September 4th, 2008, 01:29 AM   #16
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Originally Posted by Charles Papert View Post
By the way, speaking of docking "wrong"...this isn't the biggest deal and you may have figured this out, but for dynamic balance it is best to mount the docking bracket on the stand using the hole furthest from the balancing pin, so that you can get the rig as far from the stand as possible which will allow a 360 degree spin ...
That's what that hole is for - duh! I was just using the hole with the thumb screw in it as shipped.

OK, so now that I know how to get dynamic balance with the monitor all the way out, I just tried it, and it's nice - thank you! The pan inertia feels better, not a huge difference like with the weights, but a little bit more. The biggest improvement is getting the monitor more forward, so I don't have to worry about my right hand (gimbal angle off the arm post) blocking my view. It also feels like I can see where I'm going a bit more, as opposed to looking more down at my feet.

In Don Juan position, the monitor is a little further back, but that forces me to walk more sideways, which should help keep my left shoulder out of the shot (a problem I have sometimes), so that works better as well.

The only down side is that the back of the crossbar is a little longer, so I have a little more to get around when changing positions, but that's not a big deal.

Thanks!

By the way, where can I get one of those 6 foot long cameras? (LOL)

Last edited by Dave Gish; September 4th, 2008 at 02:05 AM.
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Old September 4th, 2008, 01:50 AM   #17
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Originally Posted by Julian Frost View Post
I spoke with Michael about getting the gimbal higher (closer to the camera). He advised against using many weights on the top stage as it can actually cause the metal top stage to bend/distort slightly.
That's a bummer. I thought 5 weights on each side of the stage would be OK. Did Michael give any hint as to how many weights would be OK?

I'm pretty sure 3 weights on each side of the stage would be OK, since this is equivalent to the "all weights up" configuration in the manual and in Charles' review. The smaller, round "end weights" are 2 oz. each. The normal "middle weights" are 4 oz. each. So 2 "end weights" are equivalent to 1 "middle weight".

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Originally Posted by Julian Frost View Post
I may have found someone who can make me a box for my FS-C, ... That will add about a pound to the top. Right now, there's about 4" between the top stage and the gimbal.
The FS-C weighs 1 pound by itself. The Bebob box is another 1 pound, so that's 2 pounds total. I recommended 5 middle weights on each side of the stage (10 total), which would be 2.5 pounds. So I would still get some additional weights and add a couple to the stage. For example, 6 weights would cost you $38. This will get the gimbal closer to the stage. For example, I think my gimbal is 2-2.5" from the stage.

By the way, as I understand it, the image seems more stable when your left hand is closer to the lens, so that's why I suggest adding weight up top to move the gimbal closer to the stage. But adding a FS-C box under the camera will have the opposite effect, moving the lens away from your left hand. Is there any way you can place the FS-C behind the camera? I could be all wet on this, so maybe Charles can chip in here...

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Originally Posted by Julian Frost View Post
If I keep my weights at the bottom (for now at least), I'll be maximizing the inertia, which I think will help me as a beginner, no?
Having more pan inertia will help, beginner or expert. But I think it also helps to have your left hand closer to the lens, and putting the weights at the bottom will move the gimbal away from the lens. So if you do add weights at the bottom, add some at the top also to counter-act the bottom weight, and make the whole rig more stable. That's why I suggest buying more weights.
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Old September 4th, 2008, 01:51 AM   #18
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Originally Posted by Charles Papert View Post
Julian, glad you had a good experience with customer service at Tiffen. I was actually due to go in there myself today and thus we might have met--will be going in tomorrow morning as it turns out.
Your ears must've been burning today. Your name was mentioned once or twice. :-)

It's a shame you didn't make it there today. It would have been great to meet you. I guess I could go back tomorrow, but then I think the good people at Tiffen would think I was moving in and might start charging me rent!

Quote:
By the way, speaking of docking "wrong"...this isn't the biggest deal and you may have figured this out, but for dynamic balance it is best to mount the docking bracket on the stand using the hole furthest from the balancing pin, so that you can get the rig as far from the stand as possible which will allow a 360 degree spin (this observation based on the third of your pictures from an earlier post in this thread).
Dave Gish said it best... "Duh!" I didn't even see that hole in the bracket, but now I know it's there, I'll start using it. Thanks for that!
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Old September 4th, 2008, 02:20 AM   #19
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Originally Posted by Dave Gish View Post
That's a bummer. I thought 5 weights on each side of the stage would be OK. Did Michael give any hint as to how many weights would be OK?
I don't remember specifically and wouldn't want to give out misinformation, but I think if you used the 8 supplied weights on the top stage, you'd probably be ok, but if you added more than that, you might be risking bending the frame.

Quote:
By the way, the image seems more stable when your left hand is closer to the lens, so that's why I suggest adding weight up top to move the gimbal closer to the stage. But adding a FS-C box under the camera will have the opposite effect, moving the lens away from your left hand.
Yes, that was exactly my thought, too, so I asked Michael to show me how high we could get the gimbal with what I had. We tried putting all the weights on the top stage and extending the post to compensate (which I know is not exactly what you've been suggesting as there are no weights on the bottom), and neither of us liked the way the rig flew. We briefly discussed putting the FS-C on the bottom spar and how that could be accomplished without some kind of accessory shoe. I think you're right though, the ideal place would be behind the camera. My original thought was to get the machinist to build a simple "L' bracket which would screw between the camera and the Manfrotto QR plate. The FS-C would screw to the vertical section of the L-bracket behind the battery compartment. The problem I saw with this design was that it would be difficult to change the battery in the camera. But now that I've just described my idea to you, I had another idea... attach the L-bracket underneath the Manfrotto QR *base*, not the camera plate! All I'd need would be a slightly longer mounting screw to go through the top plate and the L-bracket and screw into the Manfrotto base. The camera could be slid *forward* off the Manfrotto base when the battery needed to be changed.
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Old September 4th, 2008, 02:36 AM   #20
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All I'd need would be a slightly longer mounting screw to go through the top plate and the L-bracket and screw into the Manfrotto base.
I also used an aluminum L-bracket I got on eBay for my wireless transmitter, but after a while, I just velcroed the transmitter right to the side of the camera. Maybe something like this would work for you:
For Steadicam / Steadycam operators - eBay (item 320293927939 end time Sep-08-08 09:28:52 PDT)

In any case, if you use a round-head or pan-head 1/4-20 screw, you might need to file the screw head down some, otherwise it will scrape the inside of the stage when you adjust the stage position knobs. This happened to me. Not a big deal, but it took some time to figure out what was going on.
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Old September 4th, 2008, 03:14 AM   #21
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I wonder what adding the FS-C to the side of the camera would do to the stability of the system? I know Tiffen recommend not adding accessories to the side, but rather the front or back because of the dynamic balance issues (see the Dynamic Balance Primer). I would think that it could move the c.g. of the camera far enough to the side to put the lens significantly to the right or left of the center-line of the sled. Psychologically at least, that might have an impact on operating because the camera isn't pointing where you think it is due to parallax. Again, this is just an assumption on my part as I have no experience one way or the other.
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Old September 4th, 2008, 07:18 AM   #22
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I wonder what adding the FS-C to the side of the camera would do to the stability of the system?
Not sure. If you can get someone to make you a custom bracket that puts the FS-C behind the camera, that might be better - more pan inertia, and no side balance issues. Also, one of the reasons I stopped using the bracket for wireless is that when you hold the sled nice and close on your left, the bracket sticks out close to your head. I never had a problem hitting it, it was just annoying to have it that close.

But if the bracket is too long and the FS-C is too far back, it could be annoying clearing the FS-C with your head as you switch positions - like when you change from lens pointing forward to lens pointing backwards over your left shoulder, all within the same shot.

Whatever solution you end up with, if you need a longer screw, make sure the head of the screw is thin enough to clear the innards of the stage.
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Old September 4th, 2008, 11:43 AM   #23
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You guys are going through all the right mental paces with the gear, it is good to hear. Steadicam does require (and inspire) a lot of tinkering and experimenting to find the "sweet spot" where the rig functions in the most desirable way. What is interesting is that this is not always the same from person to person. I myself love a really inert rig but I have colleagues that like to keep theirs short and "whippy".

Dave, glad the monitor-out idea opened up some new possibilities for you. Regarding you caveat about the battery extending out (and later, the FS making for a longer camera) which requires moving it further from your body as you do side switches, these lengths are still quite short relative to the amount of movement that the arm affords you so I wouldn't consider them a problem, one spends very little time with the rig actually in front of your body (just momentarily during side switches or going through doorways) and the added inertia of length should otherwise be a worthwhile tradeoff. With certain cameras such as the Panavised F900, we have to contend with almost inconceivable configurations where the camera can be 3-4 feet long! Try getting that through a doorway...

Being such a small rig, the Pilot is going to be that much more responsive to small changes so all of the things you guys are working through are relevant, although they shouldn't get in the way of the real focus which is practice practice practice, of course. And the better you get at operating, the less small issues in balance or configuration will affect your operating--you might notice the difference but not see it in the results. I have occasionally had to muscle through takes where the rig is all fakakta until I had a chance to correct it.

Onto Julian's FS mounting dilemma. Julian, I think your idea of having it rear-mounted is probably the best and easiest, especially with the Manfrotto QR allowing you to drive the camera forward to change batteries. Personally I think it a shame to have to use the camera's own battery while there is a perfectly good one at the base of the rig, but being that there isn't a voltage regulator in the rig that can spit out the requisite 7.2v to power the camera and FS, I guess it's something to live with for the time being.

However, side mounting is not a bad idea either. The inch or two that the lens is shifted would be imperceptible to your operating (in fact, many motion picture cameras do not have the lens in line with the center of gravity due to the side-mounted motor). The other advantage of this configuration is that you are extending the mass of the camera side-to-side, which gives you some more inertia in the roll axis, which helps with the dreaded horizon issues. It would be good to give it a try in both side and rear configurations (lash it all up with tape etc) before you get anything fabricated.

Just make sure that the L bracket you use is very rigid, and is not going to vibrate under the weight of the FS. This could have a diabolical effect on the Steadicam as you can imagine.
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Old September 4th, 2008, 12:17 PM   #24
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Being such a small rig, the Pilot is going to be that much more responsive to small changes so all of the things you guys are working through are relevant, although they shouldn't get in the way of the real focus which is practice practice practice, of course. And the better you get at operating, the less small issues in balance or configuration will affect your operating--you might notice the difference but not see it in the results.
Here's my current dilemma: I'm having a heck of a time getting the Pilot and XH-A1 dynamically balanced. When I first got the rig and set it up, I must have miraculously found that sweet spot, because it was in fantastic dynamic balance straight away. Now I can't get it dynamically balanced to save my life! Charles, I know you've told me to spin the rig and look to see if it's spinning lens up, or eye-piece up, but my rig currently does both, so I'm not sure which way to move things. Nothing really seems to help! With this dilemma and your earlier statement about "practice, practice, practice" in mind, should I stop worrying about dynamic balance and spend more time flying, or will this just reinforce bad habits?


Quote:
Personally I think it a shame to have to use the camera's own battery while there is a perfectly good one at the base of the rig, but being that there isn't a voltage regulator in the rig that can spit out the requisite 7.2v to power the camera and FS, I guess it's something to live with for the time being.
I agree completely. At least I can run the FS-C from the IDX battery, if and when I get it mounted.
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Old September 4th, 2008, 12:28 PM   #25
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You guys are going through all the right mental paces with the gear, it is good to hear.
Hey - thanks for all your advice - it really helps! It's also good to hear we're doing something right...

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Originally Posted by Charles Papert View Post
The other advantage of this configuration is that you are extending the mass of the camera side-to-side, which gives you some more inertia in the roll axis, which helps with the dreaded horizon issues.
Tell me about it! This is a big problem for me. Sometimes it's quite good, but often my horizon is off level or wobbly.
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Old September 4th, 2008, 12:37 PM   #26
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Don't fret too much about DB, you are still in the "honeymoon" period with your rig and while it always helps to have it dialed in as much as possible, it won't get you into bad habits if it is a little off.
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Old September 4th, 2008, 01:17 PM   #27
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I'm having a heck of a time getting the Pilot and XH-A1 dynamically balanced... Charles, I know you've told me to spin the rig and look to see if it's spinning lens up, or eye-piece up, but my rig currently does both, so I'm not sure which way to move things. Nothing really seems to help!
1) Remember to breathe. Seriously, I got frustrated with dynamic balance at first, and had to really concentrate on relaxing. Just make sure you allocate plenty of time.

2) Make sure you have the rig in PERFECT static balance before you spin it (see my post #8 in this thread)

3) Put the battery all the way back, and the monitor all the way forward, and leave them there. Just use the hex screw in the middle of the crossbar to re-balance the weight at the bottom.

4) Try to prevent any oscillations or external forces when you spin it. Spin it carefully with your thumb and first finger level level right under the gimbal. Hold the bottom of the post loosely with your other hand as you spin it, and then let go carefully so as not to push it. Don't spin it too fast. Lightly touch the mounting yoke if it is moving after you spin it. Let it spin for a little while so any side to side swinging dampens out.

5) It also helps me to look at the rig and imagine where the center of gravity of the whole sled might be. It should be right through the vertical post. Sometimes you can get perfect static balance, but the CG of the whole sled is somewhere in the air, like between the monitor and the lens, or maybe between the camera battery and the Pilot battery. As I understand it, this is why the dynamic balance is off, because the CG of the whole sled is somewhere in the air in front of, or behind, the sled post. This can give you a clue on which way to move things.

6) Once you get dynamic balance, remember where you put things so it's easy next time. For example, after unpacking the sled from the backpack, I always extend the post by a measurement of 4 fingers. I also carefully line up the tripod plate in the tripod adapter.

And yes, I think it's important to learn with a reasonably balanced rig. You'll have to learn how to balance it sooner or later. Might as well be sooner. On the other hand, if you use the stage knob to trim the tilt of the post for proper framing, the dynamic balance will be off, so don't count on always having perfect dynamic balance.

Charles, please correct me if I have any of this wrong...
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Old September 4th, 2008, 01:30 PM   #28
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Good notes Dave.

The only thing I would correct is that when static balance is good, it means that the CG of the sled is indeed centered at the gimbal (really, slightly below of course since we make it bottom-heavy). What may not be the case however is that the line that one draws from top to bottom happens to coincide with the direction of the post. If the camera is too far forward and the battery at the bottom too far back, the rig may statically balance but the imaginary line between the battery and the camera will be a diagonal that happens to intersect the rig just below the gimbal. Dynamically balancing will bring that line straight down the post, which is what allows a flat spin. Another way to think of that is that when you spin the rig, it attempts to make that diagonal line a vertical line and that is why the rig tilts or precesses.
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Old September 4th, 2008, 01:35 PM   #29
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Thanks Charles. I guess I got the explanation from the workshop kind of jumbled up in my head. But I guess the main point is that the line of balance goes straight down through the post.
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Old September 4th, 2008, 02:28 PM   #30
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Dynamic Balance! I have achieved... Dynamic Balance!

Dave and Charles, thanks for your input on the whole dynamic balance issue. What I was seeing as I slowly (15-20 RPM) spun it was the lens would tend to point slightly up for a couple of turns, then it would tend to point down. Mostly though, the entire rig seemed to lean in or out sideways!

I initially had the battery and monitor fully extended away from each other, but after re-reading the DB Primer, I decided to move the battery in a bit, adjust the bottom spar to compensate, fine tune the static balance and spin test. No matter what I did with the battery (moving in/out per the instructions) and rebalancing, the DB got worse, so I moved everything back! :-)

Finally, following your directions, I just moved the entire spar. As the general trend seemed to be "Lens Up", I figured the battery was having the most effect on the system and was being "pulled down" by centrifugal force (ok, for you physics purists, "pushed towards the center of gravity by centripetal force"!). I moved the spar so that the battery was moved closer to the center post, rebalanced, and bingo... DB was achieved in about 2 minutes. Cool!
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