“I love to ride motorcycles—well used to before my daughter was born! Motorcycles are fast as they have exceedingly high power-to-weight ratios. Any motorcycle maker can put a big engine on two wheels and any idiot with a right hand can make that motorcycle go fast. For me, the right motorcycle wasn’t the fastest, it was one where precision and control were paired well with that power. This precision and control, when coupled with a skilled rider is harmony. Packing on 125lbs of camping gear to your motorcycle and taking turns leisurely through a Redwood forest is wonderful. Pushing the limits and scraping a peg while hanging your butt off the inside of long sweeping curve is intoxicating. The feel of power with control gives you confidence, enabling you to push the limits of your riding ability without unwelcome surprises.
For our new rigs, precision and control has been on our minds from the beginning. Coupling the right motors with the right gearing and control systems results in a motion control unit that feels right. We need to be able to hit our marks again and again with different payloads, speeds, batteries and operating temperatures. We need to do it intuitively and reliably. With that our team will help explain some technology and design choices in our new products as we strive for motion control harmony.”
– Brian Burling, eMotimo Founder
(Photo: The Denali highway in AK is arguably one of the best dirt and gravel roads you can ever take)
The right design choices will help us maintain the extraordinary position accuracy our users are accustomed to while we add speed. Precision in timelapse is a relatively easy problem to solve, but precision at speed is another thing, so let’s walk through some key terms, topics and technology, and what we think is important for a versatile piece of motion control gear for today’s filmmakers.
First of all, why do you need precision with motorized gear?
Well, you don’t…at least not in all cases. We’ll explain that a bit further with a couple simple examples.
Hot heads. These are traditionally pan and tilting heads that use DC motors with a live operator controlling them. This class of head uses the operator for feedback and control. Some would argue that these aren’t motion control since we don’t have true position control, but let’s consider that they are for this discussion. The operator uses a joystick to control where the camera is pointed. You will see these heads all over live television at the end of jib arms. It is great way to move a camera once. Good ones feel great and allow for smooth sweeping moves with damping to prevent sudden stops and starts. As long as the motion is smooth—the operator is taking care of the framing. This is the same tech that works with live sliders with un-encoded DC motors. For these applications, single pass moves that look smooth are all you need.
You can push this technology to go beyond live action in certain cases. In certain operations like slides, you can be quite “dirty” or imprecise and still have footage that looks good. Some of the most popular motorized products started with pulsed DC motors with relatively inconsistent moves and no ability to repeat a shot. In fact, the distances between those individual moves and pulses can vary a large amount and our eyes just won’t notice. The results look great in many cases and 5 years ago this capability was revolutionary. For many shooters this was still good enough because all they wanted to shoot was single pass timelapse or video. The fact that this technology is both inexpensive and works well means that many new motorized slider companies still start here. What is the catch then? With non-precise motor tech, there is no ability to repeat accurately, and applying this technology to pan and tilt looks like junk for anything other than live shots.
Why is Pan and Tilt so different than slides?
This is a complex topic that requires some serious thinking but let’s break it down with the following observations:
- 1) With a slide the majority of your background is static; only the foreground is changing rapidly.
- 2) With a pan/tilt the entire frame is changing; the background is moving most of all.
This simple concept has a few very important implications when it comes motion control gear. Pan and Tilts, if not consistent, look awful because the entire frame highlights the inconsistencies. Every single frame needs to be on target or the collective results just don’t look right. With a slide there is some wiggle room. We know from experience that getting smooth pan and tilt is the harder problem to solve. Therefore, we believe starting with the right solution for the most difficult problem is imperative.
Where is precision required?
For good quality programmed timelapse moves that pan and tilt you need motors and drive technology that are precise and repeatable for each frame you shoot. Let’s say you are taking a picture every two seconds, for a good looking shot, the motion control gear needs to have your camera pointed in precisely the right place for each shot—every 2 seconds. Both stepper motors and encoded DC motors—sometimes called servos—have the ability to always be on target for timelapse and the results look great. In fact, having a machine be on target every two seconds is a pretty easy problem to solve once you get your gearing and power transfer right.
Four years ago, the eMotimo TB3 solved this problem, and did it at a fraction of the price of other gear on the market. Since then, there have been a few good players in the market providing effective pan and tilts. Some companies use steppers, some use servos, and in many cases whatever stance they took, the opinions are strong. The other tech is wrong and inferior and we’ve seen this come through in their marketing too. Servos are better because they know where they are and Stepper Motors don’t. Steppers are better because they have higher positional accuracy at stops. Steppers are noisy. Servos are noisy. BLDC for drones and stabilized gimbals are the future. Servos saved my child and cat from a burning tree. Everyone knows dogs are better than cats and a rogue stepper motor once caught fire and…sorry, we got carried away.
Motor tech does get certain folks fired up—particularly eMotimo engineers. This is because beyond SMS (shoot-move-shoot) motion control strives for speed. To keep up, we no longer just care about where we end up every 2 seconds, we need to account for accurate positions at 1/24th of a second or 1/30th or even faster frame rates. Another way of saying this is we care as much about end points as we do about trajectory, or our path to get from one point to another. So in order to push what the TB3 accomplished forward we need to have high time on target for every frame and do it reliably.
Get to it already! What is the best technology?