Extruding Lens Element with Steadicam-like Stabilizer
Anyone using a Sony FS-100 with the stock 18-200mm lens on a Steadicam-like stabilizer knows how the telescoping or extruding elements of this lens immediately affects the pitch balance of your rig, once you zoom in for a tight shot.
Have you seen or heard of a solution for this?
If not, has anyone at least experienced this particular issue first hand?
If you have, then it's not just my imagination. Other people beside myself probably had the same experience.
Here's the good news: I solved the problem:
Here's why tight shots look good with a Steadicam:
Go ahead and build one for yourself. It works like a charm.
If you have any questions, feel free to ask.
I have to say, I might be missing something but I'm not 100% sure what this does, other than rebalancing the rig just like you'd normally have to do with any stabilizer when making a lens change... but hey, if it works for you, then it works!
Normally this is not much of an issue, because you'll rarely find Steadicam operators that use long-lens or zoomed-in shots at all, since Steadicam shots tend to work much better with shorter lenses (as evidence by the YouTube sample, the wide-lens shots were much much smoother than the long-lens shots).
Also, most cine zooms (if you choose to use a zoom) are internally-zooming lenses that don't radically affect the balance. But if you're stuck with using an externally-zooming lens that does, it's good that you've come up with a solution.
Fantastic Plastic Entertainment, Inc.
Since you've been a Steadicam user for years, you must know plenty about dynamic balance. You know how difficult it can be to re-balance a sled after changing cameras or lenses. Changing the position of the camera to compensate for an extruding lens can be just as difficult. That's why I came up with a counter-balancing solution.
Re-balancing the rig is exponentially harder and longer to do than simply re-positioning a counter-weight. It's literally the difference between minutes or seconds. I should know. It's what I had to resort to until I came up with a better solution.
Once dynamic balance is attained with the lens at it's widest, the camera doesn't need to shift from it's original position anymore. Just slide the counter-weight in the opposite direction of the zoom lens, check the pitch level of the sled, and dynamic balance remains perfectly intact.
Now I reallize most Steadicam operators avoid long-lens shots. But not always. Take another look at the video I posted, and I think you'll agree. It just looks more interesting when the camera moves smoothly while the lens is zoomed in tight. It really does.
As you probably guessed, I don't own a cine-zoom lens, and neither do many most people I've ever met. So at least my solution enables a whole range of DSLR zoom lenses to be used that would otherwise be seen as "too impractical" for Steadicam shots, or were flat out considered "impossible". It really is the poor man's solution to difficult Steadicam shots.
Seeing as how you own a Steadicam rig, you really should try this for yourself. You'll find out what I mean right away.
Sure got awfully quiet around here all of a sudden.
Well, I didn't intend to respond for fear of sounding snarky, but now I will try to answer...
I wasn't at all intending to be disparaging of your setup, which is I think the way it was received... not at all. I applaud your ingenuity in solving a problem.
My only real point is, that you ARE adjusting the dynamic balance when you move that counterweight, by definition that's what that is. After re-looking at your rig it appears that you have no additional counterweight at the bottom, where is where a lot of people make that adjustment. Since you have no weights there with your particular setup, then adjusting it at the top makes perfect sense.
I'm REAL familiar with that. I don't have that problem with any lenses, but when I shoot 35mm film just the movement of the filmstock from the front of the magazine to the back is enough to require frequent and constant fore-aft adjustment. So I end up doing exactly the same thing that you do. Thankfully it's pretty easy, the stage on my Steadicam has a little inching knob that you turn which moves the baseplate a bit forward and backward in the stage so it's not too hard, and in practicality is doing exactly the same thing you are when moving the weight. But yes, it is a constant battle, and I'm glad you have found am easy way to solve it.
What some people don't realize though, is that many cameras will have an additional issue. Move the weights like on your rig (or the stage on mine) to compensate for the lens going out will only work if your camera's lens mount is in the same EXACT left-to-right axis as the dead-center balance point of the camera. Strangely, most are not... most are a little left or right. That's compounded by the fact that the center balance point of most cameras isn't dead-center left-to-right either...things like viewfinders and handgrips make them heavier on one side or the other. That off-center lens becomes an issue because when the lens goes in and out but not exactly on the center axis, it not only affects the fore-aft adjustment you have to make (the "pitch" in aeronautical terms), but also the side-to-side balancing (the "roll"). Luckily your camera must be pretty dead-center balanced, which helps make it easy. That's just a word of warning to people whose cameras don't have a dead-center lens... while your setup will work, it might also require side-to-side adjustment as well on those cameras.
I'll stick what I say about wide lenses though. Even the top Steadicam guys stick pretty wide. One of the best Steadicam operators in the world, Guy Norman Bee (he did all the Steadicam work on E.R. and a zillion other things) says he will almost never use a lens longer than 35mm, and never use one longer than 50mm, and then only if he has to. I'm personally most comfortable Steadicamming with an 18mm or a 28mm. I think the reasoning is really evident in the YouTube clip above... the wide shots are great, but the telephoto shots obviously have a much harder time with it and float a great deal more than I think most people would be happy with. Usually the solution is to stick with a short lens but just move in a lot closer to the action.
But again, applauding your solution. Making something work is the goal.
Fantastic Plastic Entertainment, Inc.