Glidecam HD-4000 on Smooth Shooter: I did it!

[Piotr Wozniacki]

Sooo - it's been said many times that gear lust is a decease. I must admit I did it again - and encouraged by Derran's experience with his FS100 on various stabilizers, I purchased the Glidecam's HD-4000 plus the Smooth Shooter vest& arm system.

I'd like to express my gratitude to Glidecam's CEO Thomas Howie for his great help in my decision making process, and even helping me to come to terms with one of the largest Glidecam's distributors in EU (A.F. Marcotec - very nice guys, too).

Today I set up the stabilizer for the first time, and must admit it was a breeze thanks to the 3-part video by Ric Kasnoff here: https://vimeo.com/groups/cameras/videos/24063052. You can watch Tom setting up, balancing and fine-tuning the HD-2000 system with a HDSLR - invaluable lessons for a total newbie like myself!

Some of you may know that - due to my post-surgery neck spine condition - I'm just not fit to shoot hand-held for a long time, so I didn't even try my FS100 on the stabilizer on its own (other than setup testing); I put the vest on and discovered that - even though I was afraid this kind of thing is above me, with my health problems - I've found it'a actually much nicer to my weakened body that the various shoulder-mount rigs I've been building for years, to use with the EX1 and lately also with my FS100...

Of course - as Derran says - I will definitely have to exercise parts of my muscles that I didn't even know existed, but fortunately enough for me, a vest&arm system like this isn't particularly demanding on those parts of my body which I have really weakened after the surgeries (neck spine and the right arm).

So far so good, but of course it'll take me some time before I'm able to shoot anything worth posting for you guys to assess! Anyway, a whole new world of opportunities has just opened before me, so I feel pretty excited :)

[Chris Joy]

That's great. I had the HD2000 and vest with the two-part arm, can't remember the name of the top of my head, anyway I sold it with the 5d2 thinking I wasn't going to do any more steadicam shots. I modded a steadicam smoothie to fly my Nex5n and that has me wishing I had the HD2000 again to use with the FS. Woulda, shoulda, coulda... oh well.

[Piotr Wozniacki]

Although I am becoming better at exercises like following a fixed target etc., something that still is far from perfect is the camera rolls when I change direction, especially right after stopping.


Please tell me - is there any special techniques to do that? Is a properly balanced sled, with drop time of some 2.5 seconds, supposed to fly ideally vertical when I stop walking straight and start to one side? Or, is the roll or tilt - caused by inertia - inevitable, and all I can do is learn how to mitigate that with my guiding hand?

stabilized - YouTube

[Charles Papert]

Originally Posted by Piotr Wozniacki

Or, is the roll or tilt - caused by inertia - inevitable, and all I can do is learn how to mitigate that with my guiding hand? [/url]

That is correct. It's a function of a slightly bottom-heavy rig, creating a pendulum effect. One might suggest: why not make it perfectly balanced at the gimbal to avoid this, i.e. an infinite drop time, and it's worth trying to see what the problem is--without the rig having the tendency to return to level, it requires constant operator control to "make" it level, and with a lightweight rig, that just about ensures it will rarely be level!

The technique that I used to describe is that when starting a lateral move, you apply a tiny amount of force on the opposite side of the post to keep it from kicking out. We are talking a light and momentary amount. Conversely, when stopping, you do the same on the other side. Even accelerating within a shot can invite a bit of unwanted motion within the frame. It takes a good amount of practice to learn just how to control the rig through any kind of forces that are applied to it. It's part of the nuance of operating a stabilizer; it can't be shortcut, it just takes time and attention and practice.

As always, I recommend buying the Steadicam Operator's Handbook for all questions of this type.

[Piotr Wozniacki]

Thanks Charles for this encouraging info!

It's better to know something is up to you to learn and master, rather than look indefinitely into rig re-configuration :)

Piotr

[Piotr Wozniacki]

To Charles (or anyone knowledgeable):

Another thing I'd like to consult with you: obviously, horizontal and vertical balance and proper drop time can be achieved with infinite number of combinations of upper/lower weights and post lengths. However, is there a golden rule (or a rule of thumb), defining the optimum length of the sled for any given weight distribution?

Theoretically, once balanced vertically and with proper drop-time, the moment of inertia should be the same (long sled, less bottom mass vs. short sled, more bottom mass), or am I missing something?

Of course, my question is more about "optimum height to mass proportion" than absolute sled length in mm.

Edit Back to school! Just like the mass m is a measure of linear inertia, it's ml2* that is a measure of rotational inertia. So it looks like the sled inertia (or pendulum inertia) will change linearly with the mass, but with the second power of its length... In other words, out of two sleds which are balanced vertically, it's the longer one (with less mass at the ends) that has more pendulum inertia than the shorter one with more mass at the ends...

* ml2 = mass x length squared

[Charles Papert]

Glad the math works out to prove what I learned empirically, which is that shorter posts give better results. One of the things that is tough about Steadicam is that each of the three axis has different inertia, with pan the least and tilt the most, so to do a compound move like a diagonal requires just the right touch. The only reason to extend the post significantly should be if the maximum amount of camera height is required (or the lowest height in low mode). However that's usually best achieved with a longer arm post than extending the center post. I see many ads for knockoff rigs configured with bizarrely long center posts and realize that they don't understand the physics of their own gear.

[Piotr Wozniacki]

I have upgraded to the X-10 system, and it's even better now :)

[Piotr Wozniacki]

Upgrading to the X-10 double-arm has certainly improved dumping the camera movement while walking; it also doubled the pool up-down distance (obviously). But I do have another issue that I didn’t encounter before (BTW, I’m sure it has nothing to do with adding the X-10 arm):

- With a specific mass/length combination, the sled has now an annoying tendency to pendulum forth and aft. Previously – during rapid forward/backward movements – it stayed vertical; now it tends to sway.

Well, I’m an engineer so I realize all the physical laws at play – but just basing on your own practical experience with sleds of various configurations, please tell me how would you try to avoid it? By elongating and reducing the bottom mass, or the other way around?

I’m a little lost again since I’m now experimenting with a monitor mounting, and – due to the additional X-10 arm blocking my view – I’m trying to put the monitor on the left side rather than in the front of the post. Obviously, the sled “foot” is now at 90 degrees to the camera axis. I have found the (almost perfect) horizontal balance, and the drop time is close to 2 seconds – yet the increased tendency to forth-aft sway is bugging me…