Auto-rig tube flex issue

[RONDAL]

**edit**


I'm using 2 manfrotto Avenger F1000 suctions, 3 super clamps, and a magic arm.
i've also got 12' of 1.250" aluminum tubing, with wall thickness of 0.058".

When i tested it at the metal shop the flex wasn't that apparent, but now that im testing stuff before going live im getting a TON of pole flex. once i load the end of the pole with the magic arm, super clamp, d90 and wide angle, and amount of bounce in tube is unbearable.

im not getting any sharp images, even when pushing gently on flat ground.

Does anyone have any advice for how to stiffen this up?

I realize i COULD go carbon fibre, but thats like $800 for tubing and im not dropping that yet.

ive been reading all over the place and am looking for suggestions. Whatever the solution, i need it to be portable.

 

[RONDAL]

holy moly....could this be the first real beyond basics question in a while?

 

[Derrel]

Can you try and minimize the flexion by adding a guy wire? What exactly are you anchoring to?? I'm not that familiar with the suction cup's actual mounting stud or joining system; is the flexion coming from the give in the suction cup mount??? Would a "hard mount", like a bolted-on or window-mounted attachment help minimize the flexing? It seems to me that an aluminum boom arm like from my Manfrotto Super Boom is quite rigid, and does not flex very much once a load has been placed on it, so I am thinking that maybe the flexing is not coming from flex in the boom arm itself, but rather coming from the amount of free play caused by the boom-to-suction cup attachment joint.

Yes? No? Maybe?? You've probably got a better handle on this than I do, since you've got the set-up right there. Do you think a guy wire would help?

 

[GeneralBenson]

holy moly....could this be the first real beyond basics question in a while?

Seriously! This section needs way more moderating. It's become way too saturated with posts that aren't remotely advanced. I think the BTB forum should be intermediate, since that is sort of what the name would suggest, and then there should been an Advanced forum that is heavily moderated. The trend I see is that as people become more serious and knowledgeable photographers, they leave this board because there is no place for advanced shooters to talk and discuss with other advanced shooters without noobery being introduced.

Sorry for the thread jack. We will now be returning to you regularly scheduled thread.

 

[GeneralBenson]

So to reply to the OP...

Is that a joint in the middle of the tubing? Like, is it two pieces of tubing that you join together with some type of collar? That's what it looks like, and it also looks like the biggest bend in the tubing is where it looks like the joint is. Also, I think the 1 1/4" tubing with .058" wall thickness just isn't enough. I would get something a few sizes beefier than that. Good luck. Let us know what works!

 

[GeneralBenson]

I just realized that that isn't a photo of YOUR setup. So you can ignore the first half of my reply, unless yours is the same way.

Three posts in a row. Suck it, everybody!

 

[RONDAL]

i used a coupler on the INSIDE, its a 1.18" pipe that barely fits inside the 1.250" tubing. there is zero flex there, its across the length of the tube and is even.

im thinking a wire might be the way to do this, at least for now.

 

[Hardrock]

Maybe a better option would be to go through the front bumper and mount to a solid part of the car. What kind of car you mounting to? You could than angle it to the side. Are you rolling at slow speeds with a long shutter speed? I think if you are going over 20 than there will be a whole lot of vibrations from the road, engine , suspension , and the pole bouncing up an down. I dont know just some thoughts. I dont think I would trust some suction cups with a 6ft pole to hold my camera up, that is a lot of leverage at the end!

 

[RONDAL]

if you know much about rig shots, you know you dont run the engine unless you have to.
most shots are done at push speeds, walking pace or less. long shutter speeds are used for this.

suction cups are fine, and they provide more than enough force. i have hung from two of them on a metal wall, and i'm 195lbs. i use two when i attach to car, so its not going anywhere.

the mounting isn't the issue, its the pole flexing at distance.

 

[Derrel]

So...how about a Nikon with Active VR enabled??? That's designed for shooting from a moving platform, with a VR sampling frequency of 1000 hertz, according to Nikon: that should allow you to get down to some very,very slow shutter speeds with almost perfect cancellation of the vibrations. Something like the new 16-35mm f/4 VR-II lens would be the absolute widest lens I can think of that can cover FF or DX. I don't know if you shoot Canon or Nikon or Pentax or what, but I have been able to get some pretty good hand-held shots as slow as 1/3 second with my old 70-200 VR using ACTIVE mode VR, which is a tip I was taught by somebody---the theory being that Active VR is designed for a camera platform that is moving/vibrating, and a creaky human body at 1/3 second hand-holding a telephoto is, in essence, a "moving platform", if you know what I mean.

I'm thinking if you were to use two guy wires, like say stainless steel fishing wire from say the Malin tournament grade #12 wire (.029" thickness) which is 180 pound test, you could paint it with green chroma key paint and it would knock out very easily in post production, and you could use two guy wires to stabilize the pole, or maybe even three wires, one in front, one in the rear, and one over the top of the car's roof...

 

[Hardrock]

if you know much about rig shots, you know you dont run the engine unless you have to.
most shots are done at push speeds, walking pace or less. long shutter speeds are used for this.

suction cups are fine, and they provide more than enough force. i have hung from two of them on a metal wall, and i'm 195lbs. i use two when i attach to car, so its not going anywhere.

the mounting isn't the issue, its the pole flexing at distance.

Cool I didnt realize you were pushing the car(now that I reread the post I see that )! You never know what people are up to and thinking these days. My only suggestion is to use a larger/stiffer pole , or as Derrel suggested use a wire and attatch it to the end of the pole pulling down on the pole and attatch it to underneith the car. That way you have all the flex pulled out of the pole. On second thought how far apart are your suction cups? maybe the same size(diameter) pole but a little longer and the sunctions cups spread further apart? Some thoughts for ya, please let us know what you ended up with and maybe some shots of it!

 

[pyagid]

I think the easiest way would be put a tension wire on it. Put an eye bolt at each end with a wire and strainer in between (like used on gates). I dont know if it would help with the bounce enough though.

The other option would be add more material to it, maybe a piece of angle iron on both sides, make it almost into an I beam of sorts, but this may add to much weight.

-Paul

 

[KmH]

I think the easiest way would be put a tension wire on it. Put an eye bolt at each end with a wire and strainer in between (like used on gates). I dont know if it would help with the bounce enough though.

The other option would be add more material to it, maybe a piece of angle iron on both sides, make it almost into an I beam of sorts, but this may add to much weight.

-Paul

I too was going to suggest eyebolts and wire, but I think you need a much taller eyebolt in the middle and one at each end. The strainers are called turnbuckles.

So you'd actually need like 7 eye bolts, 2 turnbuckles and braided wire of sufficient gauge.

 

[RONDAL]

actually the eyebolt idea was at the top of my list.

i've seen it done almost in the exact same manner as half a suspension bridge.

run an eye hole at each end and somewhere in the middle a turnbuckle. pull tight with wire and it should help pull up the long end. at least to a point where it isn't bouncing as much.

you can always go bigger and thicker, the issue is dealing with the rig in post.
you need something non-obtrusive to make removal a little easier in PS. too big and you'll spend days cloning the thing out

 

[davebmck]

Your basic problem is that you are cantilevering a long thin beam. It is inherently unstable. I would suggest another beam, running from the bottom of the door (in the example pictured) to a point on the original beam close to the camera. This creates a triangle consisting of the two beams and the car door and will be much more rigid.

You can use guy wires as mentioned above, but wires restrict motion in one direction only. If you do this, you would need to put wires above and below the main beam to restrict its motion in both directions.