DJI RS 2 – 3D Focus System – Professional Autofocus System for Manual Focus Lenses

DJI RS 2 – 3D Focus System is an advanced focusing accessory that enables automatic focusing even with manual focus lenses. The system measures the distance between the camera and the subject and controls the lens focus using a compatible DJI Ronin Focus Motor. This makes professional video production more flexible, enabling smooth and precise focus adjustments even when the camera or lens does not support conventional autofocus.

The DJI Ronin 3D Focus System was developed primarily for use with the DJI RS 2 gimbal but is also compatible with the DJI RS 3 and DJI RS 3 Pro. Thanks to its distance sensor, compact design and integration with the DJI Ronin focusing system, it is suitable for professional videographers, filmmakers and content creators who want to use manual focus lenses in dynamic shooting situations.

The system measures approximately 63.8 × 50.1 × 27 mm and weighs around 54.8 grams. Its measuring distance depends on the reflectivity of the subject and ranges from approximately 0.3 to 10 metres. The sensor has a field of view of ±15 degrees, allowing it to measure the distance to objects positioned in front of the camera. Its compact construction and low weight make it suitable for camera systems mounted on stabilizers.

DJI RS 2 – 3D Focus System makes manual lenses easier to use by reducing the need for constant manual focus adjustments and allowing operators to concentrate more on camera movement, framing and creative execution.

Autofocus with Manual Focus Lenses

DJI RS 2 – 3D Focus System is designed to address one of the main challenges of using manual focus lenses: maintaining accurate focus on moving subjects.

With traditional manual lenses, the camera operator or a dedicated focus puller must adjust focus manually. This can be challenging when a subject moves towards or away from the camera while the operator is simultaneously moving smoothly with a gimbal.

The DJI 3D Focus System automatically measures the distance to the subject in front of the camera and transmits this information to a compatible focusing system. Together with the DJI Ronin Focus Motor, the system can adjust the lens focus position according to the measured distance.

This solution makes it possible to create an autofocus workflow with a manual lens while retaining the lens’s optical characteristics and creative qualities.

The system is particularly suitable for cinematic video productions using manual cinema lenses, older photographic lenses or other lenses without built-in autofocus.

It is important to note that a compatible DJI Ronin Focus Motor is required for autofocus operation. The 3D Focus System cannot physically move the lens focusing ring on its own.

Accurate Distance Measurement up to 10 Metres

DJI RS 2 – 3D Focus System uses distance-measuring technology to determine the distance to an object in front of the camera without relying on the camera’s conventional autofocus system.

The measuring range depends on the reflectivity of the subject’s surface. For highly reflective objects with a reflectivity greater than 80%, the measuring distance extends from approximately 30 centimetres to 10 metres.

For poorly reflective surfaces with reflectivity of approximately 5–10%, the measuring range is around 30 centimetres to 4 metres.

For objects with moderate reflectivity, the maximum measuring distance generally falls between these values.

According to DJI, the maximum detection distance when filming a person is approximately 6 metres, although actual results depend on shooting conditions and the characteristics of the subject.

This measuring range is suitable for many common video applications, including interviews, commercials, music videos and moving portraits.

Distance-measurement accuracy can also be affected by the object’s dimensions, position, material and environmental conditions.

3D Distance Sensor Enables Continuous Focus Adjustment

DJI RS 2 – 3D Focus System uses a dedicated distance sensor that measures the distance to the subject and allows focus to be adjusted automatically based on this information.

Unlike conventional camera autofocus, the system does not depend on the lens’s built-in focusing motor or the camera’s autofocus functions.

This makes distance-based autofocus possible even with lenses that have no electronic connection to the camera.

The operating principle is particularly useful with manual cinema lenses, whose mechanical focusing rings allow precise focus adjustments but do not provide automatic tracking.

When the subject moves closer to or farther away from the camera, the system can control the focus motor according to the measured distance and adjust the lens focus.

This helps reduce situations where a moving subject unexpectedly becomes out of focus.

It is a distance-based focusing solution rather than a face- or eye-detection autofocus system. The system uses a central focusing area, and its operation depends on the subject remaining within the sensor’s measuring area.

Central Focusing Area

DJI RS 2 – 3D Focus System provides a central automatic focusing area that measures the distance to the subject positioned in front of the camera.

The sensor’s field of view is ±15 degrees, defining the area in which distance measurement takes place.

This means the system works best when the subject to be focused on is positioned near the centre of the sensor’s measuring area.

For example, the system can be used to film a moving person as long as they remain in front of the camera while moving closer or farther away.

The central measuring area allows the operator to deliberately control which subject the system focuses on.

If the subject moves outside the measuring area or another object passes in front of it, the distance measurement may change and affect focusing.

It is therefore important to consider composition and the direction of the subject’s movement.

The central focusing area is well suited to controlled shooting situations where the operator can plan the subject’s position and movement in advance.

Compatibility with the DJI RS 2 Gimbal

DJI RS 2 – 3D Focus System is designed for use with the DJI RS 2 professional three-axis camera stabilizer.

The DJI RS 2 is a capable gimbal with a tested maximum payload of 4.5 kilograms. This allows it to support various professional DSLR and mirrorless cameras with compatible lenses and accessories.

The 3D Focus System expands the gimbal’s functionality by adding distance-based autofocus.

This is particularly useful when the camera operator must simultaneously control the gimbal’s movement and keep the subject in focus.

To use the system, the distance sensor must be mounted on the camera, the necessary cables connected and the focus motor configured for the lens being used.

The DJI RS 2 requires compatible firmware. According to DJI’s instructions, the gimbal firmware must be newer than v01.02.00.30.

Before use, it is recommended to check the gimbal firmware, focus motor compatibility and the mounting options for the camera and lens.

Compatibility with DJI RS 3 and DJI RS 3 Pro

Although the product name emphasizes the DJI RS 2 gimbal, DJI RS 2 – 3D Focus System is also compatible with the DJI RS 3 and DJI RS 3 Pro stabilizers.

This allows the same distance-based focusing system to be used with different DJI Ronin gimbals, making the accessory suitable for users upgrading their camera stabilizer.

For the DJI RS 3 and DJI RS 3 Pro, the connection and setup instructions for the respective stabilizer must be followed.

According to DJI’s official instructions, these models require firmware newer than v01.03.00.00.

However, owning a compatible stabilizer does not mean that every camera and lens combination will automatically work without additional accessories.

Full operation requires a suitable focus motor and a lens whose focusing ring can be driven mechanically by the motor.

Using the DJI Ronin Focus Motor

DJI RS 2 – 3D Focus System requires a compatible DJI Ronin Focus Motor to perform automatic focusing.

The distance sensor measures the subject’s distance, while a separate focus motor is responsible for physically moving the lens focusing ring.

The focus motor is attached to the camera system using a suitable support rod and mounting hardware and is connected to the lens focusing ring through a gear mechanism.

If the lens does not have a suitable gear ring, an additional lens gear strip may be required.

After installation, the system must be calibrated so that the focus motor knows the lens’s focusing range and can adjust focus correctly.

When properly configured, the distance sensor and focus motor work together to provide autofocus functionality for a manual lens.

It is important to note that the DJI Ronin Focus Motor is not included in the standard 3D Focus System package and must be purchased separately if needed.

Compact and Lightweight Construction

DJI RS 2 – 3D Focus System is designed for professional camera systems, making its construction compact and relatively lightweight.

The device measures approximately 63.8 × 50.1 × 27 mm and weighs around 54.8 grams.

Its small dimensions allow the sensor to be mounted on top of a camera without occupying excessive space or making the camera system unnecessarily bulky.

The lightweight construction helps limit the additional weight placed on the stabilizer, which is particularly important for handheld gimbal systems.

Although the sensor itself is lightweight, the weight of the focus motor, mounting hardware, cables and other accessories must also be considered when balancing the gimbal.

A properly balanced camera system helps ensure smooth stabilizer operation and reduces the load on its motors.

Mounting in the Camera Accessory Shoe

DJI RS 2 – 3D Focus System is designed to be mounted on top of the camera so that the distance sensor can measure the distance to objects in front of it.

The package includes a 1/4″-20 threaded cold shoe adapter, allowing the sensor to be attached to a compatible camera accessory shoe.

This mounting method is practical because many photo and video cameras have a standard accessory shoe on top.

The sensor must be positioned so that its measuring area points towards the subject and is not obstructed by the lens, lens hood or other accessories.

When installing the sensor, the gimbal’s range of motion must also be considered to ensure that the sensor and connecting cables do not interfere with the movement of the gimbal axes.

After mounting the sensor, the stabilizer may need to be rebalanced.

USB-C Connectivity and Power Supply

DJI RS 2 – 3D Focus System uses USB-C connections for data transmission and power.

The device has two USB-C ports that allow it to be connected to a compatible DJI Ronin stabilizer and focusing system according to the manufacturer’s connection diagram.

The USB-C connection allows the distance sensor to transmit the information needed for focusing and operate as part of the DJI Ronin focusing solution.

The device does not require a separate replaceable battery because it receives power through its USB connection.

This reduces the need for additional batteries and charging accessories and helps keep the overall camera setup more compact.

When connecting the device, suitable cables must be used and the connection instructions for the specific stabilizer and focus motor must be followed.

Smooth Focusing When Filming Moving Subjects

DJI RS 2 – 3D Focus System is particularly useful when the subject is constantly moving relative to the camera.

For example, when filming a person walking, the distance between the camera and the subject may change rapidly.

With manual focusing, the operator must continuously monitor focus and adjust the lens focusing ring in such situations.

The DJI 3D Focus System allows focus to be adjusted automatically through cooperation between the distance sensor and focus motor.

This can make tracking a moving subject more convenient and allow the camera operator to concentrate more on controlling the stabilizer and framing the shot.

The system is suitable for moving portraits, commercials, music videos and various cinematic scenes.

However, its performance depends on the subject’s position within the measuring area, its surface reflectivity and the mechanical focusing characteristics of the lens.

Practical Solution for Cinematic Video Production

DJI RS 2 – 3D Focus System offers new possibilities for videographers who prefer manual focus lenses because of their optical characteristics and creative flexibility.

Manual cinema lenses are widely used in professional video production because they provide precise focus control and often feature consistent mechanical focusing movement.

However, using these lenses for moving shots can be challenging, particularly with shallow depth of field.

The DJI 3D Focus System makes it possible to enhance a manual lens with distance-based autofocus, helping simplify the recording of moving shots.

This can be useful for both independent videographers and smaller production crews without a dedicated focus puller.

The system does not replace professional manual focusing in every situation, but it provides an additional tool for simplifying the shooting process.

Suitable for Interviews and Portrait Videos

DJI RS 2 – 3D Focus System is well suited to situations where a person is positioned in front of the camera and moves moderately forwards or backwards.

During interviews and portrait videos, the subject may lean forward, change position or move slightly away from the camera while speaking.

When using a lens with shallow depth of field, even relatively small movements can affect image sharpness.

Distance-based autofocus helps compensate for these changes as long as the subject remains within the sensor’s measuring area.

This can make interview recording more convenient and reduce the need for continuous manual focus adjustments.

The system is particularly suitable for controlled shooting environments with planned framing and lighting.

Use in Challenging Lighting Conditions

DJI RS 2 – 3D Focus System measures subject distance using a dedicated sensor, so its operation does not depend on image-based camera autofocus in the same way.

This can be useful in situations where conventional camera autofocus struggles with low contrast or challenging lighting.

For example, dim interiors and film shoots using controlled artificial lighting may present difficulties for some camera autofocus systems.

Using a distance sensor offers an alternative method of adjusting focus in these situations.

However, sensor performance depends on the reflectivity of the subject and environmental conditions.

DJI does not recommend using the system in dense fog or measuring through glass surfaces. Very poorly reflective objects or unsuitable surface materials may also reduce the measuring range and affect reliability.

Lens Calibration for Accurate Focusing

Proper calibration of the lens and focus motor is essential when using DJI RS 2 – 3D Focus System.

Because the system controls the focusing ring of a manual lens using a mechanical motor, it must know the lens’s focusing range.

During calibration, the focus motor’s operation is configured according to the characteristics of the lens being used.

This helps ensure that the measured distance corresponds to the most accurate possible focus position.

If the lens is replaced with another model or the position of the focus motor is changed, the system may need to be recalibrated.

Correct calibration is particularly important when using lenses with shallow depth of field, where even a small focus deviation can cause the subject to appear out of focus.

During setup, DJI’s official instructions and the mechanical characteristics of the lens should be taken into account.

Reliability and Environmental Limitations

DJI RS 2 – 3D Focus System is intended for professional use, but its distance-measuring performance depends on the surrounding environment.

The device’s official user guide specifies an operating temperature range of 20–45 °C.

The sensor’s measuring range depends on the reflectivity of the object and may be significantly reduced with dark, transparent or poorly reflective surfaces.

For example, glass, water surfaces and very dark materials may cause distance measurement to perform differently from expected.

Using the system in dense fog or measuring distance through glass is also not recommended.

For the most reliable results, the sensor should be directed towards a clearly distinguishable subject positioned within the measuring area and at an appropriate distance.

Before important shoots, it is advisable to test the system under the specific lighting and environmental conditions.

Included Accessories

The standard DJI RS 2 – 3D Focus System package includes the distance sensor and the basic accessories required for mounting and connecting it.

The package contains the DJI Ronin 3D Focus System distance sensor, which measures the distance to the subject.

It also includes a 1/4″-20 threaded cold shoe adapter that allows the sensor to be mounted in a compatible camera accessory shoe.

A 30 cm USB-C Multi-Camera Control Cable is supplied for connecting the system according to DJI’s instructions.

It is important to note that the DJI Ronin Focus Motor required for autofocus operation is not included.

The package also does not contain a DJI RS 2 gimbal, camera or lens.

DJI RS 2 – 3D Focus System – Professional Autofocus Solution for Manual Lenses

DJI RS 2 – 3D Focus System is a practical and technologically advanced accessory that enables distance-based autofocus with manual focus lenses.

The system measures the distance to the subject in front of the camera and controls lens focus using a compatible DJI Ronin Focus Motor. This helps simplify filming moving subjects and reduces the need for continuous manual focus adjustments.

The device measures approximately 63.8 × 50.1 × 27 mm and weighs around 54.8 grams. Depending on the reflectivity of the subject, distance measurement operates over a range of approximately 0.3–10 metres, while the sensor’s field of view is ±15 degrees.

Its compact construction, USB-C connections and compatibility with DJI RS 2, DJI RS 3 and DJI RS 3 Pro stabilizers make it a versatile solution for professional video production.

DJI RS 2 – 3D Focus System is particularly suitable for videographers, filmmakers and content creators who use manual focus lenses and want to add autofocus capabilities to their DJI Ronin stabilizer. Through distance-based measurement, a compatible focus motor and thoughtfully designed integration options, the system helps make the shooting process more flexible and supports the creation of smooth, professional-looking video footage.