Learn to Read the Spin Test - A Guide for Achieving Dynamic Balance with Your Steadicam

Timestamps:
00:00 - Introduction
00:37 - What you need to do before the spin test & an important process to remember
03:17 - Purpose of spin tests & basic physics behind the dynamic balance
06:23 - Spin test results, how to read them & physics that help you understand them
10:29 - External links of useful knowledge (This is important too)

Useful Links:
Steadicam Dynamic Balance Quick Guide - by Chris Fawcett
   • Steadicam Dynamic Balance Quick Guide  
(The section that Master Chris talks about the pattern behind the 3 masses' positions is at about 2 minute mark in that video)

A Dynamic Balance Primer - by Jerry Holway
https://people.ok.ubc.ca/creative/Gli...

Music Credit:
Sail Away - by AG Music
Bright Day Ahead - by Geoff Harvey
Elegant Commercial Piano - by Roman Cano
from Melody Loops

Additional Notes ↓↓↓
There is a brilliant question being asked in the comment section about how one would assume naturally to move camera forward if sees the lens tilts up, I then realized I didn’t do a good job explaining this clearly enough in the video. After that, I took some time to think about how I should explain it a bit further and I wrote this reply which I just copy-and-pasted here for anyone who might have the same question. Hopefully this could clear up some of the confusions, if so, it’ll be great:
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“
There are 3 masses we are dealing with here, camera on the top (C), sled batteries (B) and sled monitor (M). The sled will only be in dynamic balance when all 3 masses are in the spatial positions relative to each one another.

Figuratively speaking, it is much like trying to solve the equation of “C + B + M = 10”. Besides the infinite combinations of the positions there are, what we are aiming to do in the video is to fill in the numbers into the equation, so that we will reach one of the infinite combinations that 100% gets the sled in dynamic balance.

In the video, once we have the monitor in the desired position, we will never move it again during the rest of the balancing process. Figuratively speaking again, this is like algebra, now we have “C + B + 5 = 10”.

In the rest of the balancing process, we put/fix the camera on the top in position, and then get the sled in static balance by changing the battery position only. Once done, we do the spin test. If the sled spins in dynamic balance, it means we hit the jackpot and now we have reached at one of the infinite solutions. (It could be “2 + 3 + 5 = 10” or “1.3 + 3.7 + 5 = 10”, so on and so forth…, we just wouldn’t know exactly the value and yet we don’t need to know.)

If the spin test does not show the sled spinning in dynamic balance, we change the camera to new position (this act will ruin the current static balance), and we’ll need to get the sled back to static balance again by changing the battery to an also new position. We repeat this process until the sled spins in dynamic balance during the spin test.

***

With the understanding of the above, when the lens tilts up during the beginning of the spin test, it does NOT mean “back heavy”. Remember, our sled should be in static balance in the first place, before the spin test. Therefore your camera does not make your sled back/head heavy.

What you are observing (the lens titling up), is a combined effect of the pendulum and the spin. Dynamic balance is the spin without pendulum. The pendulum is caused by the camera being away from the pivot point.

P.S.
Ideal situation to prove there is a pivot point, imagine camera in the dead center on top with 2 equal weights on the sides of the bottom of the sled. This will be a “0 + 5 + 5 = 10” situation.
”