Camera kits

Wireless Lens Control Systems – all you need to know

Wireless lens control systems (WLCS for short) have changed enormously over the last 10 or so years and have evolved from being a luxury option on a kit list to becoming a necessity on virtually every shoot.

Whilst the traditional systems continue to be popular, their functionality has been developing and there has been an explosion of new solutions in the market.  One such development is to offer compatibility with both film and now also DSLR lenses. Another trend is towards camera & WLCS brain integration, so that less external modules are required on camera to make systems work, affording greater efficiency.  

However compatibility is not universal across all makes or cameras and with so much variation in cameras, lenses and Lens Control Systems, how do you choose between them?  

This article aims to explore this question and introduce the range of WLCS systems which VMI considers the best in their field and explain why we think that they work very well in given scenarios.


This is a complex subject to introduce in a single document, so in order to make it easier to read, we have broken this down into 6 sections and each is a hyperlink.

  1. Introduction to the basic principles 1/2/3 axis, single or multiple handset control, film/DSLR lenses
  2. Using Electronic Lens Data
  3. Integrated or Modular
  4. The Nuts and Bolts
  5. Summary of Wireless Lens Control Systems
  6. Conclusion

Section 1: Fundamentals

1 axis, 2 axis or 3 axis?

The first question to ask is how many channels or axes will be required?  

A single axis WLCS system will only control focus; a 2 axis system, both focus and iris and a 3-axis system will control Focus, Iris and Zoom.  The F, I & Z (in Focus, Iris & Zoom) explains the initials of the popular Preston FIZ3 WLCS systems by the way!

The main advantage of single channel WLCS systems are that they are lightweight due to the on-camera receiver (or ‘brain’) being small and only 1 axis control means that only 1 servo motor is required.  Simply put, less servos = less weight.

2 Axis systems control 2 x servo motors which control both focus and iris controls wirelessly.  If only prime lenses are being used for example, then no zoom function is required and so a 2-axis system will suffice.  Gimbals for example require both iris and focus control, as the light levels may vary during takes, especially if the shot has a transition from interior to exterior.

Even if you are using zoom lenses, then a 2 axis system may still be sufficient, since the camera operator may choose to operate the zoom control locally and under these conditions a 2-axis system would still suffice.  Some dedicated 2-axis systems do exist, such as the RTMotion or new Preston MDR4, however all 3-axis systems will still function as 2-axis systems if only 2 x motors are connected to the brain.

Single or Multiple Handset Control

Another consideration is whether to have a single hand unit (HU) or 2 x hand units.  Some single hand unit designs allow control of all 3 axes so that one technician can control Focus, Iris and Zoom, whereas a dual handset design will facilitate 2 x technicians, each with their own distinct handset, to control focus/iris on one and zoom/iris on another.   Some other systems allow for modular handset construction depending upon requirements (e.g. ARRI WLCS2/3 series units).

Other systems provide all 3 axis controls on 1 handset (ARRI WCU-4 and RTMotion 3-axis system) but this is of little use if you have 2 technicians who want to operate focus and zoom controls independently, so unless you are working on a crane installation or similar where one operator wants to control all 3 axes, then triple axis controllers are less useful.

A more common approach is to use a 2-axis WLCS system allowing the focus puller to operate iris and focus control on one handset and for the camera operator to control zoom using a separate Microforce controller and this can be mounted/connected in many different ways depending on immediate needs, brain choice etc.

The most sophisticated systems allow for every combination and permutation of control, which helps to explain their popularity on large dramas and big budget films.  These often have separate operators controlling iris, zoom and focus, where the ubiquitous Preston FIZ3 is standard issue.

Are you using Film or DSLR Lenses?

Another consideration is to choose a lens control system appropriate to the type of lenses that you are using.  Until recently, lens control systems were only used on modern film lenses and the large size of traditional film lenses meant that the motors used were commensurately powerful.

However, increasingly, as production methodology has changed with the introduction of drones, gimbals and compact large sensor cameras requiring more versatile configurations, so wireless lens control has become more important. Their ability to adapt to lighter-weight setups now includes being able to wirelessly control DSLR lenses, when an appropriate mount is fitted to a suitable camera.

Whilst modern film lenses are solidly built to withstand harsh treatment of powerful motors clunking hard against their end stops, this does not apply with DSLR lenses due to their lightweight design.  Similarly, some vintage lenses, even if remounted into modern lens housings, may retain their original internal mechanics within the new housing and so be less able to cope with harsh treatment from some lens control systems.  

Whilst lightweight lenses at best may not actually be compatible (many DSLR lenses don’t have end stops at all), at worst, lenses can actually be damaged by using inappropriate lens control systems.

The initial calibration process is potentially the most damaging to delicate lenses, since this is the function which occurs when a WLCS system is first activated and all 3 motors automatically move throughout their range until they reach the end of the range of each axis, hit the end stop and then do the same in reverse, so lenses having end stops is crucial to their operation when working with WLCS systems.  

More gentle calibration techniques are adopted with the newer series systems, e.g. RTMotion, Preston MDR3/4 etc, which avoid this problem and can really help to prevent damage in delicate lenses. (Usually referred to as “soft” or “gentle” calibration) These systems also have selectable torque, or motor power levels.

Also, the absence of end stops in many DSLR lenses and reverse focus direction of some lenses (e.g. Nikon) also precludes some WLCS systems from being used.  In order to use these lenses, you will need both programmable end stops and also a direction reverse function, such as the Hocus Axis 1; RTMotion and Came-TV systems, among others.

Section 2: Electronic Lens Data

Using Electronic Lens Data - Pre-marked rings or custom marked rings?

‘i Data’, or “LDS” enables electronic focus mapping for lens control systems, avoiding the calibration process entirely and also eliminating the need to manually mark separate rings for each lens.  

Traditionally, the focus puller dedicated at least a day to marking up individual focus discs for each lens on a production. Preston introduced “lens mapping” in 2006, where, as the ring was manually marked, its position could also be recorded by the LCS. This has become especially useful recently with the increased popularity of Vintage glass.

ARRI were early pioneers in making available continuous electronic remote readouts of precise focus settings, T stop and focal length information from electronics inside their “LDS” generation lenses.  This was initially recorded “off board” in order to benefit the cinematographer and post production workflow, particularly on complex CGI/Film based shoots. With the advent of digital cinematography, it was an easy step to add this as metadata to the electronic image files. This increased “sharing” of lens data enabled many manufacturers to radically improve upon the traditional analogue Lens Control Systems available, with the newer, far more intelligent systems available today. This has resulted in huge time savings in equipment prep and lens testing for camera assistants, with the ability to use “pre-marked” focus rings, and many of the newer systems giving live depth of field information, amongst other things.

The electronic lens data, (referred to by Cooke Optics as ‘i data’) was first introduced in their Cooke S4i lenses in 2005 and is now replicated in many modern film primes including Cooke S5i, Mini S4i & anamorphic S4i; also ARRI Master Prime, Master Anamorphic and ARRI LDS Ultra Primes amongst a select group of others.  Also some PL zooms from Angenieux and ARRI Alura offer this data functionality too, though even across common product groups, this facility is not always universal.

Electronic lens data, when integrated with appropriate hardware and cabling, enables a camera to recognise the lens being fitted by its electronic data and match this to its lens library data, so that pre-printed focus marking rings can be used across many lenses and in doing so, no calibration is required when lenses are changed.  Thus by using electronic lenses, lens data is ‘pre-mapped’ into the WLCS system and the focus puller can immediately accurately pull focus from a single set of pre-marked focus rings across all compatible lenses.  

Focus mapping makes life easier for the focus puller and this clearly saves time during preparation and operation.

The ARRI WCU-4 WLCS system goes a stage further and the LCD display of the hand unit also gives additional graphical information of the depth of field preview, which can be very helpful to camera crew. 

The full open source interface between Cooke lenses and ARRI WCU-4 is not yet completely automated, as some manual mapping is required in prep to be able to use pre-marked rings and Depth of Field preview information.  Cooke are aware of this and an improvement in this area is planned for the very near future.

The Preston FIZ Systems whilst fully compatible with all LDS/i-data systems currently need an additional cable between the lens and the brain in order to display the lens data however the lens mapping is completed from the HU3 internal lens library.  However, when the “brain” is not reading directly from the lens, pre-programmed markings are only “best estimates” of the true lens position, and may cause potential problems in certain situations, so this is to be avoided whenever possible.  

Clearly with older/manual/rehoused/vintage lenses, the manual marking-up of focus rings to match lens measurements is the only solution as they will not have any internal electronics. Consequently they have to be calibrated and marked in the usual/traditional manner.

Beware that not all lens mounts on all cameras have the same levels of functionality, so if in doubt, test, test, and test again.


Cinetape Integration

Both the Cooke ‘i system’ and ARRI LDS system can be integrated with the Cinetape measuring system on both the ARRI and Preston WLCS systems.

Cinetape has been the Industry-standard focus measuring tool to allow accurate focus measurements to be available in both a clear readout to the camera operator/focus puller and electronically integrate to many WLCS systems too.  This integration is only available on the most expensive systems.

There are other, more complex/intelligent systems available too (e.g. Preston Light Ranger 2 (LR2), however these would require a separate paper to discuss in full)

Section 3: Integrated or Modular?

The traditional design incorporates a Hand Unit control, ‘brain’ to affix to the camera and servo motors which connect to the ‘brain’, which also requires powering.  A recent development has incorporated the WLCS receiver ‘brain’ to be integrated into the camera to make setups simpler and improve functionality.  This was pioneered with the ARRI Alexa PLUS/Alexa Mini and recently a new collaboration between RED and OFFHOLLYWOOD has created a new “RED PLUS” LCS system too, offering multi-manufacturer compatibility.

The ARRI Solution

ARRI began to integrate the LCS function into the design of the ARRI Alexa in 2012 with the introduction of the ARRI WCU-4 WLCS system. These were designed to be compatible with the ARRI Alexa Plus.  This combination allowed the servo motors to be connected directly to the camera body to reduce the set up time considerably. 

ARRI refined this still further in 2015 with the release of the ARRI Alexa Mini which also integrated with the same ARRI WCU-4 WLCS controller but this time incorporated a daisy-chain of lighter-weight C-Force motors to simplify the wiring capability still further (instead of each motor being plugged into the camera, just one motor is plugged into the camera and the other motors daisy chain from it).

The integration allowed for greater functionality: being able to display lens data on the monitor and camera preview screens and, for the first time, enabled camera functions including remote start, colour balance, frame rate adjustment etc. to be controlled wirelessly from the ARRI WCU-4 hand unit.  The elegance of this system is clear when using an ARRI camera/WLCS system but until recently, precluded using cameras of other makes, as these did not have the integration function built-in.

Happily, ARRI have changed this now with the introduction of external receiver/brain modules, which now allow universal compatibility of ARRI WCU-4 with cameras from all manufacturers (ARRI UMC-4 and AMC-1 external ‘brains’ make this now possible).

The ARRI system also records the metadata which is provided from the lenses and this can be very helpful in post-production.  Note the Preston FIZ system records the metadata to external USB stick, not Alexa.

The RTMotion/RED/EF Solution

RTMotion are a British firm who make excellent WLCS systems and although they work universally with all cameras, they are specifically designed to integrate with RED Cameras and to this effect, they have 2 x distinct solutions and both are provided in VMI RTMotion WLCS kits for hire.

The regular RTMotion 3.1 system works as a traditional 2 or 3-channel system with a separate on-camera ‘brain’.  However, it can also work in a new special EF only mode when using the optional Latitude MDR ‘brain’ module. (**Note only works if the correct EF mount is fitted to the camera**) This mini brain is designed to integrate electronically with modern RED cameras fitted with an EF lens mount and using EF lenses.  This configuration is compatible with either RED DSMC1 or DSMC2 bodies and includes the new EPIC-W and Weapon varieties as well as the previous RED EPIC Dragon.

By connecting the Latitude brain to a RED camera fitted with EF mount and using EF lenses, you can use the RTMotion WLCS hand unit to control iris and focus and this will drive the motors built into the lenses without using externally mounted servo motors.  The absence of motors and large brain gives a corresponding weight saving which can be really helpful when working on a drone or gimbal system.  

Optional Thumbwheel Control Option

If you are using a Gimbal system, another trick is to be able to control focus on the EF lenses (also using the built-in lens servos) by using externally mounted thumbwheels.   This optional extra is also included as standard with VMI kits and you don’t even need to use the remote hand unit for the operator to be able to drive his own focus using the thumbwheel – you just need the Latitude ‘brain’ and thumbwheel.



An iOS app called FOOLCONTROL allows remote control of RED camera functions and users can use Latitude's built in WIFI to Foolcontrol a DSMC1 camera that has no WIFI capability and to extend the WiFi range of DSMC2 cameras too.

The device running the Foolcontrol App needs to be used within range of the Wi-Fi built into the Latitude Receiver. Range is highly variable due to the nature of Wi-Fi, but probably maxes out at 30-40 metres. The Latitude's WIFI will give better connectivity than the built in DSMC2 WIFI, but still maxing to this range.

Latitude allows you to control; EF/AF Lenses (Iris/Focus), Shutter, ISO, R/S, Button features (CAL - Auto calibrate EF/AF, MAG - 2x Magnification, EDGE - Focus assist ) on RED with 4 configurable Controller axes - Focus knob, Iris Slider, A and B wheels (eg. A and B wheels can be used for Shutter/ISO) plus 4 configurable buttons (for camera button features or RT button features). 

The RTMotion/RED/OMOD Solution aka RED PLUS

The introduction of the OFFHOLLYWOOD OMOD Command module takes integration to a whole new level with RTMotion, and other soon-to-be announced Lens Control systems all effectively built into the latest RED cameras.

Put simply, the RED EPIC-W/Weapon camera docked with this new device creates a similar functionality to the integrated ARRI camera/WCU-4 system to effectively make a RED PLUS camera.

The RED EPIC-W, Weapon or similar (DSMC2 body) docked to OFFHOLLYWOOD OMOD Command RT module turns the RED camera into an integrated RED PLUS system, which, in common with the ARRI model, allows the lens control motors to plug directly into the camera system

This adds the following functionality:

MōVI Pro/MōVI M15/Hocus Axis-1

Gimbals and Drones by their very nature require wireless lens control, so it was simply a matter of time before a hardware integration offered additional functionality to make this easy.  
The MōVI Universal Controller offer such integration with the Axis 1 remote focus ‘brain’.  Once configured, the right joystick controls the gimbal camera pan/tilt function and the left knob controls the focus adjustment of the Hocus Axis 1 WLCS on the gimbal.  

Note that this integration also works with C-Motion systems as well and is planned to have compatibility with the RTMotion system in time as well.  


The right curvature and feel – the importance of Muscle Memory

I understand on good authority that years of pulling focus with a focus knob of a given diameter and feel will necessarily mean that muscle memory plays an important part in ensuring that focus pullers are comfortable using WCLS systems of different models and makes and so being able to do their job.

Given that the industry standard WLCS system is the Preston FIZ3, then this is the yardstick by which all others are compared with and as a result, ARRI and C-Motion systems also share the same diameter focus ring and feel to the Preston, so that transition to these different manufacturers for technicians is an easy substitution.

Whilst some focus pullers are more amenable to change than others, it is important to establish that your chosen system is going to be acceptable to your crew and for this very same reason, VMI deliberately only keeps certain types of WLCS systems.

Left or Right-Handed Operation?

It does seem odd that with 12 percent of people being left-handed, no current WLCS systems are particularly well suited to left-handed focus pullers.  However, the 3-axis ARRI WLCS series III incorporates a hand unit which feels very similar to the Preston HU3 but with the focus knob on the top of the hand unit rather than the side.  This innocuous design element usefully allows it to be operated with either hand, thus allowing for either right-handed or left handed operation.  

So if you have any leftie focus pullers in your crew, it is probably worth mentioning the ARRI WLCS series III to them to win more brownie points!

Section 4: The Nuts and Bolts

Here are some simple questions to ask before you embark on ordering a WLCS system.

Section 5: Summary of Wireless Lens Control Systems

Here is a summary of WLCS (Wireless Lens Control Systems), that VMI carries from stock.  This is not an absolute list of ALL systems available.

Single Axis Systems

Hocus Axis 1 Wireless Lens Control System ££

The Hocus Axis 1 is a single-axis wireless lens control system with a fast and punchy motor, compact receiver and 200m range.  

Equally at home driving film or DSLR lenses, it has a direction reversal function and programmable end stops. Its compact and light weight design makes it ideal for shoulder work and its compatibility with the MōVI wireless controller makes it suitable for Gimbal work too.  

However, be aware that this is single axis, so won’t drive iris and focus simultaneously.

Came-TV DSLR Wireless Lens Control System £

The Came-TV system is a low cost single-axis wireless lens control system which we suggest is specifically suitable for DSLR and low cost productions, though it can work with film lenses.  Due to its cost and specification, it only has a 60m range (30m in built-up areas) and like the Axis 1, includes a direction reversal function and programmable end stops.  

What is unique though about the Came-TV device is that the transmitter can work with its integral rechargeable batteries, so you won’t need to worry about a 12V D-tap power source on the camera, so perfectly suited to DSLR or compact cameras if used with their own compact batteries.

Its compact and lightweight design make it suitable for lightweight shoulder work and Gimbal operation too, though the limited transmission range may make this this unsuitable.  Also, the reduced power of the servos and lack of start-stop cables are reflective of its budget status, so won’t successfully drive some film lenses either.

Preston FIZ Lite Wireless Lens Control System ££

The Preston FIZ Lite is a single-axis version of the popular 3-axis Preston FIZ system.  

The system is supplied with the Preston F/I handset as standard, however the marking rings on this control are not the same size as the standard HU3 unit. Using the same motors as the larger FIZ 3 system, it will drive the heaviest film lenses and has a suitably impressive range compared with other wireless lens control systems.  The DM2 motors are not the smallest or lightest, but all crews will be immediately at home when using it.

Importantly, due to the lack of programmable end stops, it is unsuited to working with DSLR lenses.



Dual Axis Systems

RTMotion  2 Axis Wireless Lens Control System ££

The RTMotion 2-axis wireless lens control system is a 2-axis wireless lens control system which has an incredible 1.5km range to control focus and iris wirelessly on the supplied hand unit controller and offers extensive integration with RED cameras, courtesy of the Latitude receiver module (supplied with VMI kits) especially when used with the OMOD Command RT module (see later entry).  

The Latitude brain for RED DSMC2 cameras extends the range of the lens control function to 1.5km and also allows the RED camera functions to be operated up to 1.5km away.  This means that not only can you control focus and iris from a distance but you can actually playback images on your iOS device (courtesy of the FOOLCONTROL iOS app) wirelessly making it extraordinarily well-suited to Gimbal applications.

The soft calibration function is standard, making it suitable for any lens and programmable end stops also make it suited to DSLR lenses too.
The thumbwheel controller also allows control of focus locally and this connects to the Latitude controller too (provided as standard with VMI packages).

Whilst RTMotion do make a 3-axis system, VMI do not stock this yet, as we feel that operators are more likely to control the zoom function with an external local zoom drive, obviating the need for a wireless 3rd axis control.


Three Axis Systems

Preston FI+Z3 Wireless 3-axis Lens Control System ££££

The Preston FI+Z 3-axis WLCS is the standard by which all other 3-axis lens control systems are compared.

Full 3-axis control with all combinations and permutations possible.  The hand unit has controls for the focus iris and zoom functions for the camera assistant. 
The system can be used with pre-marked rings to interface with suitable i-data or LDS lenses and configured with Cinetape measuring device.

The Preston Microforce zoom controller is the industry standard zoom drive controller and can be mounted locally in/on around the camera in many ways, depending on immediate needs.

ARRI WLCS Series III Wireless 3-axis Lens Control System £££

The ARRI Mark III WLCS system offers full wireless control of zoom, focus and iris and includes 2 hand controllers, one for focus/iris and one for zoom.

The system can be operated via radio or remotely controlled via a cable and full 3-axis control with all combinations and permutations possible.  The hand unit has controls for the focus iris and zoom functions for the camera assistant. 

The Series III WLCS system will interface with Alexa Plus cameras to avoid the need for a WLCS brain. Most importantly, the ARRI WLCS series III hand unit can be operated by left or right-handed operation users.

ARRI WCU-4 Wireless 3-axis Lens Control System £££

The latest generation integrated ARRI WCU-4 Wireless Lens Control system is a modular system originally dedicated to ARRI cameras but now able to work with all non-ARRI cameras as well, when used with optional separate brain/receivers.

This modular system is specifically designed to work with ARRI cameras including Alexa Plus, Alexa XT Plus and Alexa Mini, to avoid the need for a separate brain/receiver.  The design permits the lens motors to connect directly to the camera body, allowing wireless control of zoom, focus and iris from a single wireless hand unit (WCU-4).

Like the Preston units, ARRI also supply pre-marked rings to work with LDS and lenses equipped with i-data and will integrate with the Cinetape distance measuring device as well with appropriate cables.

However, unlike other systems, not only can the elegant LCD panel display depth of field and other lens data (assuming that LCD/i-data lenses are being used) but you can also access the camera’s menus remotely to change ISO, frame rate, setup, trigger etc. all from the same controller.

The complication is that there are many different types of motors compatible with either the Alexa Plus/Alexa XT Plus (CLM 2/3/4 motors) or the more compact Alexa Mini (C-Force Motors).  The wiring is slightly different (C-Force motors have daisy-chained wiring), so ensure that you are clear when ordering what cameras you are working with, otherwise you may be provided with an incompatible version.  For this reason, we market a WCU-4 Alexa Plus version or WCU-4 Alexa Mini version (Note that the latest C-force+ motors have dual compatibility but having the correct cables is still critical!)

Until recently, ARRI WCU-4 systems could only be used with ARRI cameras, but the introduction of external brain/receivers means that that these systems are now compatible with almost all camera systems, though the remote camera functionality is limited if working with non-ARRI cameras.  Depending on choice of motors used, the integrated WCU-4 system uses either the WCU-4/UMC4 version or the WCU-4/AMC-1 version.

The WCU-4 system can utilise pre-marked rings to work with suitable i-data or LDS lenses and also configured with Cinetape-style measuring devices.

The VMI WCU-4 system is supplied with a single hand unit to operate focus, iris and zoom and whilst ARRI do now make a second-generation separate zoom drive, which can work locally or wirelessly, we have yet to stock these devices as the Preston Microforce is usually preferred.

Section 6: Conclusion

With such a range of devices and functionality available and at so many budget levels, it pays to be clear about what you need and why before deciding on equipment choices, as you may be able to afford a more elegant system without spending any more money or even saving some money.

Firstly, decide how many axes you need to control and what sort of lenses are to be used, whether film or DSLR before making a choice and then look at all of the options carefully before making a decision.

The traditional and expensive systems made by Preston offer the most versatility but lack some of the integration options which a few operators have come to appreciate.

The ARRI WCU-4 systems offer excellent integration with ARRI cameras and now can be supplied with external brain/receivers to work with all cameras, although you lose some of the control advantages.

New tools by OFFHOLLYWOOD with the OMOD COMMAND RT offer superb integration with RTMotion WLCS systems and more compatibility with other systems are promised for the future but these will ONLY work with the latest or previous generation RED cameras – so great if you want to work with RED EPIC-W, WEAPON and Dragon cameras but no good if you are using Canon, Sony or Panasonic cameras.  

Our advice is to be clear about what you need to achieve and then choose the most appropriate system to work for you.

Click on the chart for an elarged comparison table













Barry Bassett January 2017
With thanks to Howard Preston of Preston Cinema/Milan Krsljanin of ARRI for detail checking.

Every effort has been made to ensure that this article is accurate but we cannot be held responsible for any ommissions or innacuracies.


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Ric Swift - UK Wildlife Film School 6 days ago

Wow, Thank you for this Barry. It is a very in-depth read on a very interesting subject… much to learn from the information in here.

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