Yet another DIY steadicam, with a monopod

N

neekoh

Member
I tried to put together something that I could just quickly setup with the gear that goes with me anyway.
Here's a test: http://vimeo.com/12747827
The description / photo probably tell more.
I started with balancing the monopod, then added some more "configurability" and inertia around the monopod axis and finally just added a ball bearing as the inertia wasn't enough. This became monostab :tongue:. Obviously it's not perfect, but the benefit can definitely be seen and it goes easily along and didn't cost much. I haven't shot video much, but plan to use this shooting an old geezers' karting event later this week. I'll post if it turns into anything fun / worth sharing.
 
Lynchenstein said:
Yup, this is definitely up my alley. Any chance of a DIY guide for this?
Click to expand...

Hi, I don't know how much a complete DIY guide makes sense. For example, it's highly unlikely to find the same exact parts. But I can of course explain my logic, list the steps I took to come up with the current "design" and list the parts. It may give you an idea of what you could use. Minimal engineering / machining skills were needed. I wasn't even going to consider a gimbal head or anything very sophisticated, and really wanted something that would easily go with me.

The logic part is quite simple.
Theory: The more general inertia (=mass) the system has, the less it is prone to shakes along each main coordinate axis. The more rotational inertia the system has the less it is prone to small tilts around any of the main coordinate axis. As a huge generalization: a system that has most of it's mass far from the mass center, has a large rotational inertia around the mass center.
The mass of a dslr alone is quite great. Maybe not great enough to reduce the positional shakes, but still most of the shakes are small tilts. So the system needs more rotational inertia. Because of the camera's mass, we don't want it to be the the mass center. To keep the total mass reasonable it should rather be suspended some distance from the mass center and add counter-weight to balance the system.

This is the first thing I did, and the basis of many "emergency" on-the-spot steadicams and DIY ones. I put the camera on the monopod and duct-taped a dumbbell weight to the other end. Then I tried to find the mass center by having the monopod sideways. Once close enough, I took a pinching grip of the monopod and noticed that the lens wants to tilt it forwards. I taped a wrench on the dumbbell to balance it better. The balance was still off, but closer. Without a gimbal head you can get away with small balancing issues by a firmer grip, but this of course brings more movement from direct contact with your hands. I took a few test shots and was surprised to see it doing very well already. The problem was that with each step I took I involuntarily twisted the monopod and shots were spoiled with sideways motion.

The next thing was to add rotational inertia around the monopod axis. I was actually thinking of some kind of metal sheet that I could fix weight to and that I could somehow fix to the monopod. I was running a completely different errand in a hardware store, when I spotted the "mooring compensator". I passed on it once but went back with the tripod later. I found that the tripod fits the holes nicely and it was actually a bit difficult to get it off. I then went to a compartment with all kinds of screws and bolts and whatnot and there were some heavy duty bolts. I found a diameter that fit the holes nicely and picked three slightly different lengths for some possibility of adjustment. They weighed almost a kilo together and with the mooring compensator would make a good counter-weight.

It was now very easy to switch between monopod and "steadicam" and balancing for different lenses was easy. However the test shots still showed the same sideways motion although a bit more restrained now. I didn't want to add any more size or weight, so I was thinking about adding a bearing around the monopod somehow. Another hardware store sold all kinds of bearings. They had these "jointed bearings" that allow for axial tilt (10º or so). I was thinking they'd be perfect! Like a simple gimbal head. But once I got one in my hand it was obviously not that good. It wasn't a ball bearing and the movement, rotation or tilt, was very stiff. Obviously meant for something completely different, like car suspension rods etc. perhaps. So I went with a normal ball bearing, which seemed really sensitive. They had one with inner diameter of 30mm which I thought I might be able to fit through the top of the monopod. Another shop sold them for really cheap so gave one a shot. I had to disassemble the ball head on the monopod to ease the ball bearing through. There was a small tooth left on the metal to stop the ball head locking screw, which I just sawed away. The locking screw could then be turned to completely come off and the ball head split in three parts nicely. The fit was closer than I'd measured, but enough for the bearing to be slid through. Most effort was needed in getting the bearing on the handgrip foam. I squeezed the foam inside the bearing hole with a flathead screw driver and slowly eased it downwards. Once past the top end I could just slide it into place. It takes enough force that it doesn't move around at all when in use. If you have a slightly bigger one, I'm sure it can be wedged in place quite easily. Then I put the ball head back on, found a balance for the camera and weights and went to test. I need quite a firm grip of the bearing with three fingers. The good thing is that I can tilt the camera a bit when needed, but I also accidentally then do it. The bearing does it's job well, though, and compensates for most of the sideways motion. When walking, it seems to pass through some of it, but when running it's almost completely gone. To pan the camera I gently brush my ring finger against the monopod next to the bearing. This seemed to work ok. This the current situation, as seen in the video. I don't have any immediate improvement ideas, I'll first try to use this for something.

The parts:
Monopod Velbon RUP-L43 with the ball head.
http://www.velbon.co.uk/newvelbon/pages/monopods.html

The mooring compensator seems to be this one, the largest size. I don't know where if they retail outside Scandinavia.
http://www.unimer.se/int/Product.asp?PageNumber=189&Product_Id=373

Bolts... well any that fit the purpose. Mine were sold by the weight and the store had a lot to choose from.

Ball Bearing, inner (axle) diameter 30mm, outer diameter 62mm
Mine was this one from here:
http://www.biltema.fi/osteri/osteri.cgi?tuote=41409&sivu=41409.htm&ryhmaid=

Sorry I didn't realize I would be so exhaustingly long-winded. Just watch this afterwards on a related topic: http://www.youtube.com/watch?v=_dPlkFPowCc
 
Nice I need to build one of these but kinda lost on part sources in the USA.

What is the bonding sheet you talk about. Not sure what this is.

Do you have any pictures of the rig?

Thanks.
 
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Yeah neekoh some pictures of the rig would be really nice if you get a chance. Also fantastic footage, really nice improvement between your two pieces of footage.
 
Sorry, haven't checked back... I only have one image, the one linked to the vimeo page as well: http://www.flickr.com/photos/neekohfi/4723543752/lightbox/
I don't have any more detailed ones, but that shows the parts. The "bonding sheet" (yeah, looked it up on the dictionary :D) is just a metal plate with screw holes. The one you can see screwed on the rubber right at the bottom. It's just for rigidity in my case, not a required part.
 
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