Advanced Steadycam DiscussionI’ve added this section in response to a surprisingly large number of individuals who are apparently amateur physicists or even certified mechanical engineers who sometimes write fairly long emails pointing out problems with this design or offering a variety of suggestions. I would like to spend the time to respectfully acknowledge each comment sent to me, but unfortunately that is becoming impossible as the number of these emails is increasing. What I would first like to say is:1. I am very happy that my steadycam tutorial is inspiring people to think about the physics and engineering problems involved with creating a steadycam, especially if they did not do so before. As a general concept of promoting the awareness and appreciation of the power of science in our lives, I think this is wonderful. I encourage people to invent their own designs and explore different configurations. 2. I do have a degree in engineering and am currently working on a doctoral degree in a related field. I have completed several advanced courses in physics and have spent a year doing motorsports engineering (which I will say is extremely fun and amazing). I realize that this steadycam design is incredibly simplistic with several limitations. But in terms of cost, availability of materials, construction time, and necessary skills, I have yet to see a better solution (despite all the suggestions). Though, I appreciate hearing them. And I'm sure that one day, someone will prove me wrong. Frequent Suggestions: Suggestion: You should use part X from a tripod or use the tripod itself. Reply: True, you can get pretty decent results simply by using a tripod with its legs folded together (perhaps with an attached weight), and the mounting head on a tripod is certainly better than a simple bolt. But, it’s hard to find a tripod of decent quality for under $30. I assume you don’t have a tripod handy, or have one you are willing to destroy, in which case, $14 is less than $30. Suggestion: This steadycam sucks and isn’t nearly as good as a real steadicam Reply: Thanks for the constructive comment. I never said it was as good. A $4000 rig with body vest and supporting arm IS going to give you better results. Can you afford a $4000 rig? If the answer is yes, you have no reason to be reading this tutorial. Suggestion: This really needs a gimbal. Reply: This magical "gimbal" has some weird religious following that I simply don’t understand. These gimbals are just two axis hinges that eliminate any control over pitch and roll, place a tremendous amount of stress on the wrist, and produce pendulum effects when you move (from not being at the center of gravity). A gimbal is not critical to the existence of a steadycam and I personally dislike them. A handle with ball joint IS NOTHING like the hinge systems used in professional rigs. They are gross immitations that do more harm than good becauase they are doing it wrong. Suggestion: You should have a + shape or upsidedown Y-shape so the steadycam is perfectly balanced. Reply: These have their advantages, and their disadvantages. The current design is slightly imbalanced due to its T-shape. However, the weight of the side handle is probably only 5-7% of the total weight of the steadycam with the camera. The effect of this imbalance is small when held by an operator, and disappears completely with practice. The symmetric designs cost more, make the unit more unwieldy, and may not provide a convenient or obvious handle. From an ergonomics standpoint, the T- shape is better. Suggestion: The bottom weight should be exactly the same as the camera. Reply: Every camera weighs different. Scales with ounce or gram precision are not common making it difficult for people to weigh their camera and weights sold in this precision are also not easy to come by. If you have access to these, that’s great! More power to ya’. But 2.5lb or 5lbs barbell weights from a sports store is a close enough approximation for most people with consumer grade cameras. This can also be reasonably overcome with practice. Suggestion: PVC or aluminum bars would be better than steel Reply: You are free to use what ever material you choose, but I liked steel piping because it is strong and comes pre-threaded - no cutting, no gluing, no welding. I can collapse the steadycam for storage and re-assemble it less than 30 seconds without using any tools. Suggestion: How about a gyroscopic stabilizer? Reply: This idea certainly may help. But, until you can show me a self-contained gyroscopic stabilization system than cost less than $1 and doesn’t require recharging. I think I’ll leave that part out. Don’t lose that imagination though. Suggestion: How about using springs or bungee cords? Reply: This is one of the better questions I get and one of the more difficult ones to answer. The short answer is that springs are deceptively simple looking devices that are surprisingly difficult to work with. Rarely does sticking the whole thing on an elastic support provide the desired results. The longer answer is that spring support systems are usually combined with damping mechanisms to reduce oscillation, and it is the *careful* balance between the strength of these two components that will produce the right kind of behavior within a limited window of load weight and forces. They don't teach spring systems in school until you are in an advanced college physics course because even the simplest spring models require second order linear equations (differential equations beyond basic calculus) and imaginary numbers. It's not easy stuff. But if you decide to skip the physics models, you *might* get lucky with some random trial and error at your hardware store. However, regardless of your luck, any spring system design will be much more mechanically complex than the current design. It gets substantially more difficult to build and harder to work with because it's behavior becomes orientation dependent due to gravity. Suggestion: Center of gravity! Torque! Moment of inertia! Lever! Mass! Balance! Acceleration! Force! Reply: Yes, I am impressed by your physics vocabulary and yes all of these concepts are quite relevant in designing a steadycam. No, this design does not really address these except in the crudest manner. Yes, I know this. No, I’m not going to change the design. Yes, I do understand physics. No, I do not think I am a ninny. There are thousands of improvements that could be made to this design to become the world’s best camera stabilization tool. But, things get much harder to build and much more expensive very very quickly. As soon as you do that, you are missing the point of this original design and why I created this tutorial. If you poke around www.steadicam.com, you can find documents that go into a deep discussion about the physics behind thier stabilizers and learn about thier "Dynamic Balance" system. I refer you to that if you are interested in learning about these more sophisticated (and expensive) solutions. |
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