REVIEW: RT Motion MK3.1 Remote Follow Focus Kit

A high-quality remote follow focus that upgrades easily from one channel to three.

I’ve been on a bit of a remote follow focus kick lately, looking at a couple of affordable units that offer a lot of bang for the buck — ikan’s Remote Air One ($1499) and Cinegears’ Wireless Follow Focus Express ($1989). 

But I thought I was done writing about follow focuses for a while, until I came across one more that should definitely be on the radar of anyone looking for a system that can grow with them. 

It’s RT Motion’s MK3.1 kit, which is made in the U.K. and priced around $4672 (given current exchange rates) for a single channel system. That’s at least a couple grand more pricey than the other units I’ve reviewed lately, but the beauty of the MK3.1 is that you can buy the single channel system for focus now and easily and relatively affordably upgrade to a two channel system (focus and iris) or a three channel system (focus, iris and zoom — aka “FIZ”) down the road. 


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To add channels to the MK3.1, you don’t have to buy a different controller, because the controller you get with a single channel purchase already has controls for iris and zoom built-in. You also don’t have to add additional receivers for those extra channels since the MK’s standard receiver (which is tiny, by the way) can already manage three channels from the start. 

To add iris or zoom to your system, all you need are additional motors, and those cost about $2000 — a little more expensive that typical motors because they include some electronics that you’d otherwise find in a receiver, but still respectable for a high-quality, low-noise, brushless motor. 

So that’s why I tracked down the MK3.1. For roughly the same, you can get similar straight-forward but high quality single-channel systems like the Heden Carat or the Axis1. But with those, you’re locked into a one channel solution for good, with no way to expand later on. 

Anyway, I got a chance to work with the MK3.1 for a few weeks (as a single channel system), and was really impressed with everything about it. Here are some  impressions, along with a demo video….




  • The MK3.1’s controller feels great in your hand, with a slider for iris control and an optional force-sensitive thumbstick for zoom (an upgrade that costs about $1050). There’s also a dial (labeled ‘A’) for adjusting the speed of the thumbstick’s zoom, and another dial that you can use to control zoom if your controller doesn’t have the thumbstick option (‘B’).
  • The controller uses a small screen to dial in various settings, which makes it easier for a newcomer to figure out how to do basic things like automatically calibrate a lens, manually calibrate a lens to specific start/stop marks, reverse the direction for the focus wheel, and so on. 



Control iris with the slider, and zoom with the A and B knobs, or the optional red thumbstick seen here.  


  • It’s powered by a small Canon LP-E6 battery (you can provide your own or order one from RT Motion) which lasts somewhere in the range of 30-36 hours of average use. In my mind, using an LP-E6 battery is a little inconvenient because it’s one more battery you have to manage in your gear inventory (the Remote Air and Express have internal batteries that you can charge via USB) but the benefit is that if you start running into battery problems, it’s easy to just slip in a fresh one. 
  • RT Motion also makes a wired thumbwheel controller that single operators can mount on a shoulder rig or Steadicam. Price is about $385. 




  • The MK’s 3-channel receiver seems a bit of a marvel because it’s so small and lightweight — just 118 grams compared to, say, the 218g of the iKan or the 130g of a Heden Carat, which are both single channel receivers. RT Motion was able to drop some weight from the receiver by moving electronics into the motors themselves, but those aren’t exactly bulky or heavy either — 212 grams versus a standard Heden’s 250g. The connection cable between motor(s) and receiver is also thin and flexible, so it’s easy to route through a rig. Anyway, the receiver and motor’s low weight make the MK3.1 an especially great option for steadicam and gimbal work. 



This is one of the smallest receivers I’ve come across, and by far the smallest that supports up to three motors. 
  • Since the Mk’s receiver expects some necessary circuitry to be in the motor, that means you can’t use popular motors or cables from other systems. 
  • Besides connections for up to three motors and power, the MK receiver also has an AUX port for a Record trigger cable, so you can start/stop a camera’s recording from the MK controller. Supported cameras include the Alexa, Epic, Sony F55, Phantom Flex, and Black Magic cameras. There’s also a Serial port for physically connecting an option thumbwheel controller that a sole operator could mount on a rig, or to directly attach the standard controller when wireless signals are a no-no (hospitals, etc.). 



The MK3.1’s motor is quiet, smooth and zippy. 




  • The controller and receiver use a 2.4GHz radio, and automatically pick the best of 42 channels to work together at boot up. 
  • You can auto-calibrate a lens with a couple of button presses on the controller (press Menu, then choose the first first menu option for RECALIB and then choose AUTO CAL). The motor hits the lens’ hard stops gently, giving you a reassuring feeling that you’re not wearing down your lens day-after-day. 
  • Overall precision is great. Zooming back and forth between my hand-drawn marks on the controller’s focus wheel always brought the motor exactly where it was supposed to be on the lens. (The digital motor has 1000 different position values and the OLED shows you exactly which one the motor is on). That’s not always the case with lower end systems — for instance, iKan’s Remote Air’s motor would sometimes drift a millimeter or two from where I had marked it on the lens, occasionally affecting focus. 
  • As for responsiveness, the MK’s controller lagged behind a little bit when I was doing very big, quick twists with the focus wheel, but that’s the case with all systems I’ve come across. Still, the MK controller actually lets you put the motor into a mode tuned for big, quick moves, and that does indeed improved responsiveness.  


lcd screen

 You can figure out pretty much everything just by scanning through the viewscreen’s menu options. 
  • Manually calibrating a lens without hard stops, or to just play within a certain range of a lens, is easier with the MK3.1 than with any other system I’ve tried, thanks again to the OLED menu system. Press the controller’s Menu button, and choose the first option for RECALIB, then MANUAL CAL, then FOCUS, and then use the controller’s UP/DOWN arrow keys to set your Start mark and your End mark (all following on-screen prompts). It goes very quickly and it’s easy to figure out on your own.  
  • Another common function — switching the direction you turn the focus wheel in relation to the direction the motor turns the lens — is also made easy with the LCD menus. Press the Menu button, then the FLIP KNOB menu. Done!
  • In terms of the MK’s range, I tested through a few dry walls within 40 feet of the transmitter, and then across an 80 foot driveway line of site, which the MK handled perfectly. RT Motion says the 2.4GHz MK can theoretically work across up to 1.5 kilometers line of sight, but that’s in the best of conditions. Realistically, RT Motion recommends dividing that by three for realistic line-of-site applications, and dividing by 8 if you expect trouble-free operation in busy, obstacle-riddled environments. 
  • Speaking of range, you actually specify the signal strength for controller depending on the kind of range you want (check the WIRELESS menu on the OLED screen, then choose POWER). The controller’s default signal setting is LOW, which works for operations relatively near the camera, like the tests I did. But you can boost signal strength to MED and also USA MAX or EU Max for greatest reach. One thing to look out for though: if you have the controller set for Medium or Max strength, it can have a hard time finding the receiver if you’re standing right near the camera). So if you find connectivity to be an issue, bring the controller back to a LOW setting. 





The one issue you should weigh carefully when investing in a system like the MK3.1 is the fact that RT Motion is a small company based in the U.K with no dealers in North America, or elsewhere for that matter. All support and shipping is handled by RT Motion, and with that goes some of the familiar woes of dealing with a small, far-off company. For instance, I’ve noticed some existing customers complain about waiting days for email responses from customer service, and longer-than-expected waits for replacement gear, along with the higher costs of overseas shipping. When your gear has issues, that kind of stuff can drive you crazy. RT Motion also currently has a 4-6 week lead time on getting new orders shipped, and that’s been the case for at least several months.

There’s also been a lot of competition lately in wireless follow focuses, and some promising developments on the horizon such as the TiltaMax 3-channel system to be distributed by iKan (though, to be fair to products actually shipping, the TiltaMax has been “shipping real soon now!” for more than a year and a half, and still hasn’t made it out the gate). 

Having said all that, I personally wouldn’t let any of that dissuade me from investing in an MK3.1. RT Motion has been in business for years, selling multiple versions of the MK, and developing a good reputation for quality among users I’ve come across. My own experience with the MK has been rock solid, and I’m not aware of any other system that gives you not only a great single channel option, but also an easy and relatively affordable path to upgrading to iris and zoom control as well. 



  • Very good price for a single channel system that expands to two and three channels (about $4700 to start)
  • Tiny receiver supports up to three channels and record/stop features
  • Responsive and precise
  • Controller’s LCD screen makes it easy-ish for newcomers to figure things out on their own. 
  • 2 year warranty


  • If you only care about a single channel system, you can find them for much less money
  • Potential for slower, less convenient support due to working with a small, overseas company 



Helmut Kobler is a Los Angeles-based DP and cameraman at





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Helmut Kobler is a DP and cameraman based in Los Angeles, California. He’s shot for networks such as Discovery, The History Channel, the BBC, PBS and others. Corporate work includes projects for Microsoft, American Express,…

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