Friday, December 11, 2009

How to balance a fluid head

How to balance a fluid head
Just as it is obviously important to balance a jib arm, it is equally important to balance one's fluid head, especially if you are putting it on a jib arm. Unfortunately, I have found over the years that it is not uncommon for people not to know how to balance their fluid heads. When they are only working on a tripod, they can get by with it not being properly set-up, but when it's on a jib, an improperly set-up fluid head can inhibit the jib's movement considerably. You will find yourself booming the jib when all you wanted to do was tilt the camera. So if you are having trouble hitting your marks with the jib, before you blame the jib, or yourself, have a look at your fluid head.
I worked in a camera rental facility for many years and it was common to watch camera assistants simply muscle the head around a bit, dial in some fluid drag that felt appropriate, and think, "Yeh, that's good." They did not do any balancing at all, and that really is not the correct way to do it.
Almost all fluid heads have locks for the pan and tilt, fluid drag adjustment for pan and tilt, and usually an adjustment for the spring tension on the tilt. The better heads have a continuously adjustable spring adjustment which is ideal for accurately dialing in the balance. Others have a lever (or levers) to either engage or disengage a spring (or springs). Unfortunately, the really low-end heads often do not offer a spring adjustment. For those of you who have an adjustable spring, here is what I recommend:
1) Put the camera on the head and lock the tilt axis.
2) Set the fluid drag setting to zero, so that when you unlock it, you will only have the spring affecting the tilt.
3) Unlock the tilt axis and balance the camera fore and aft on its sliding balance plate. We haven't adjusted the spring yet, so it will probably want to fall either backward or forward, but it should have the same response in either direction. In other words it should be centered so that it is neither front nor back heavy. You can fine tune the fore/aft position once the spring is set properly.
4) Now set the spring tension. Heads like those made by O'Connor or Cartoni generally have continuously adjustable springs so you can dial in the tension accurately. Others like Sachtler have preset spring choices that allow you to either engage or disengage various springs and these will get you very close. Either way, you now want to set the spring. To do this, tilt the camera forward about 45 degrees to see what it does as you begin to let go of the panbar. If the camera wants to continue falling downward, then you need more spring tension. If it pulls upward when you let go, then you need less spring tension. Dial in, or manipulate the on-off levers, to find the right tension.
5) If the camera is balanced fore and aft properly, and the spring tension is set properly, the camera should always stop exactly where you point it as you let go of the pan bar.
6) Now dial in the desired amount of fluid resistance for the tilt and the pan.
7) And this brings me back to my original point--that is, for a jib arm, this will be using very minimal fluid drag. You want a floating feel to the movement of the head just like the floating feel of the jib arm itself. As I said above, you do not want the jib to boom when all you want to do is tilt the camera, which is what will happen if the drag is too strong. On a tripod, you may prefer more resistance, but on a jib you want a light, floating feel.

Please take the extra few minutes to properly balance both the head and the jib. It will make your work much more satisfying. For those of you unfamiliar with our Vector Balancing System, please read those instructions as well.

Thursday, December 10, 2009

Front vs. Rear Operated Jibs

A few notes for those of you new to the world of jib arms, and who may be confused about the difference between front-operated and rear-operated systems.

People tend to use the words “crane arm” and “jib arm” interchangeably these days. Originally, a crane was a much larger unit, usually carrying a camera operator and assistant as well as the camera. A jib was a smaller unit carrying just the camera. However, the important distinction these days is not whether you call it a crane or a jib, but rather whether you operate it from the front or from the rear, because even though these systems look very similar, they are not really the same tool. Porta-Jibs are primarily used as front-operated devices, (although our Standard Jib can be rear-operated as well--more on that later).

Let’s start with understanding the basics of a rear-operated system. Rear-operated units need to have a way to remotely pan and tilt the camera. Be aware that some of the inexpensive ones do not even pan the camera, they only tilt via a cable, and panning can only occur by panning the entire arm rather than the camera head itself, which means you cannot do a very sophisticated compound move. However, more typically, rear-operated systems will be more complex than that, and will have a pan and tilt head that either is driven by motors or by a cable system, so that you have the ability to pan and tilt the camera as well as boom and pan the jib itself. The advantage of these systems is that they can position the camera far higher than one could hope to reach if manually operating the jib from the front and also be able to reach out over things.

So the question becomes: why would one want to operate from the front, when the rear operation gives one so much more range of motion. This is where it becomes a question of the using the right tool for the right job. If what you want is extreme height and reach, then obviously you want a large jib with a remote head controlled from the rear. If however, you want to make more subtle movements in the 2-to-8 foot range, then a front-operated jib is the way to go.

In this case, you simply place a fluid head (that you typically already own) onto the front of the jib. You already have good intuitions of how to pan and tilt the head, since you probably have been doing this for years on your tripod. So when you need to follow a complex action on a jib, which do you suppose is easier to master--front-operation with a fluid head or rear-operation with joysticks? Let's suppose you are following an actor who suddenly stands up and moves across the set, and your job is to keep him framed in the center of the camera's view. Imagine trying to make a quick speed change, a pan-tilt motion, and a boom up while operating from the rear with joy-stick controls. Then imagine trying it with a front-operated jib, where the speed change and framing come easily because you are comfortable doing that with your fluid head. So all you are adding to the mix is the booming motion. It should be obvious which will be easier to master. Furthermore, the lower the shot the more difficult it becomes for the rear operator because now his hands need to be well above his head as he is trying to get the camera to low position. True it can be done from the rear by experienced operators who make a living at being remote head operators, but a new client will often be reduced to using his jib only for very easily controlled high angle moves.

So if height is what you need, then the remote head is for you. But if what you wants is to add movement to your everyday work where the camera tends to stay in the low to mid-height range, then clearly a front-operated jib is the way to go. No additional batteries for motors are needed, a far quicker set-up time is obtained, and generally a much lower cost, because low-end remote heads start at around $2000 to $3000, just for the head without the arm. When you think of which type of shot is far more prevalent in everyday production -- a floating movement in the less than 8 foot range, or the birds-eye view of scene – obviously, for most clients, the front-operated jib is the more useful tool.

The Porta-Jib is primarily a front-operated type. However, having said that, we need to point out that although we do not make a remote head for jibs, our Standard Jib does have the capability of adding an additional 3 foot extension to lengthen the front arm, so often customers will choose this version to use with another manufacturer’s remote head. That way they will have the capability of working either from the front or the rear as the job’s requirements dictate.

The Standard Porta-Jib as a rear operated jib arm

Wednesday, December 9, 2009

About this blog

Occasionally people ask about things that I think are obvious about our products at Porta-Jib, but, as it turns out, clearly are not. And after explaining something to them, they often say, "Oh, now I get it." My conclusion is that I need to work on communicating some of these points better, and therefore, I thought a blog might be a good way to augment what is on the website.

For example, it seems that people don't understand why we added, what we call, the "Vector Balancing Bar" to our jibs, or why we think our Seat Assembly for the 4-Leg Spider Dolly is truly unique in the world of lightweight dollies, or why one would invest in an underslung head as opposed to a traditional fluid head, or why it is critical to adjust the settings on the fluid head completely different when on a jib arm as compared to when it's on a tripod, and things like this. So when I feel inspired, I will try to jot down some of these notions, and hopefully they may prove to be helpful.