DJI released the RS 3 and RS 3 PRO, and also officially launched the DJI Transmission wireless image transmission. The long-awaited ultra-long-distance image transmission is finally available! DJI's wireless image transmission products have also officially entered the field of film and television shooting as an independent film and television equipment.

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structure appearance

 

In 2016, when DJI released the Mavic Pro drone, OcuSync image transmission could achieve a ground-to-air distance of 7 kilometers. At that time, many film and television practitioners were looking forward to DJI's application of the powerful image transmission system in film and television shooting. Since then, OcuSync image transmission has been continuously updated in drone products. It was not until last year that OcuSync O3 Pro was officially applied to DJI's Ronin 4D movie camera. Since then, DJI's wireless image transmission has officially entered the field of film and television shooting .

Ronin 4D Image Transmission System

DJI Transmission comes with a transmitter, a receiver , and two batteries. Unlike other image transmission products, this one uses the WB37 smart battery, and is also compatible with NP-F series batteries via an adapter. In addition, it also comes with cables and a tool wrench, so you can use it right away.

The transmitting end

The transmitter is square-shaped, with vertical raised lines on the front. This small detail design has two obvious functions:

① Enhanced heat dissipation effect : Compared with a whole piece of metal panel, metal strips can better guide air and achieve heat dissipation;

② It is more convenient and safer to take and put : This design can increase the friction, thereby achieving an anti-slip effect; after all, even if the internal structure is perfect, the antenna of the image transmission cannot withstand the risk of impact.

There is also a nameplate on the front, laser engraved with the brand logo and the function of the product, which is very DJI-style. At the same time, this area is also convenient for labeling . On the set, one set of wireless image transmission is obviously not enough. Whether it is used as a backup or for multi-camera shooting, the management of multiple sets of image transmission is very important. Use color labels to stick to this area, and you can quickly select and use them .

The left side of the transmitter is relatively simple, with three operation buttons. Under the antenna is the power button, which requires a short press to start and a long press to shut down, so there is no risk of misoperation ; below the power button is an LCD screen for displaying parameter information, which is very intuitive .

 

At the bottom is a knob with the DJI logo and a BACK button. These two buttons can be used to perform all settings and operations on the transmitter. At the same time, there are two protective metal sheets outside the knob to prevent the knob from being dislocated due to breakage or collision .

The other side of the transmitter is full of interfaces, including two BNC SDI interfaces, one for input and one for output, and a full-size HDMI input interface , which can be used to input video signals for machines without SDI.

 

The Type-C port next to the HDMI port can be used to update the firmware , which also leaves many possibilities for later use. The bottom is a LEMO power port , which makes the power supply method very diverse. In addition to the independent battery clip, you can also use the D-TAP output of the V-mount battery and the Type-C port output of the stabilizer to achieve power supply.

The transmitter is covered with heat dissipation holes, and the shape and color matching are full of technological sense

There is a battery hanging plate on one side of the transmitter, and a cold shoe hanging plate can be installed on the other side. It can be directly mounted on the bottom of the quick release plate of RS3 PRO, and can also be used for the cold shoe interface of other cameras or camcorders, greatly enhancing its practicality.

Receiving end

After looking at the shape of the transmitter, let’s take a look at the appearance of the receiver. The receiver of this wireless image transmission adopts an integrated design for receiving and monitoring. Unlike traditional pure receiving devices, the integrated receiving and monitoring end is more convenient to use, just like the Ronin 4D uses the transmitter as a built-in module. The higher the degree of integration of the product, the more stable and quicker it is to use.

 

The front of the receiver is occupied by a 7-inch high-brightness screen with 1500 nits , and the layout of the screen is also very reasonable, which we will explain in detail in the monitoring section.

The receiving end is also relatively small, with a height similar to a can of cola.

There is a battery compartment and expansion interface on the back of the receiving end, but the bottom protective cover needs to be removed to expand the use of DC power supply, SDI input and output and other functions; on both sides are heat dissipation scales, which are the same as the structure on the transmitting end, which can increase the heat dissipation area and increase friction, thereby achieving an anti-slip effect .

A brightness of up to 1500 nits will naturally bring about higher heat. All unused areas on the body are also equipped with heat dissipation vents to keep the heat as low as possible so as not to have a negative impact on the screen display.

There is a power button and indicator light on the left side of the screen, which allows you to clearly see whether it is in working condition. At the same time, there is a rabbit cage on the outside of the receiving end to protect it, which greatly prevents accidental touching of the power button.

The interfaces on the right side of the body are relatively abundant. From top to bottom, they are 3.5mm monitoring interface, TF card slot, HDMI output interface, and Type-C interface. For a small team, these interfaces can be used in most models and scenarios; if they are not enough, the expansion interface on the back can also meet more professional needs.

Replaceable expansion interface on the back

They are DC power supply, HDMI and SDI output

 

 

Performance Testing

 

Transmitter performance parameters

Receiver performance parameters

Judging from the parameters, the transmission performance of this image transmitter is very powerful. In addition to the diversity of operating frequencies and transmission powers, it is also compatible with a wide range of input and output formats. Even when connecting to older devices, there is no need to convert the format through an adapter.

 

001 Distance Test

We have all seen the distance of the image transmission on DJI drones. This is mainly ground-to-air transmission. In this process, obstacles and signal interference are far less than ground-to-ground interference. DJI image transmission is claimed to be able to achieve an ultra-long distance of 6 kilometers under FCC conditions, but the prerequisite for achieving this condition is no interference and no obstruction.

 

There is no such flat and open space in Chongqing, the mountain city where we are located, so we choose a longer distance for testing as much as possible; before this, the equipment we tested was no more than 1 kilometer, which did increase the difficulty of our testing.

OcuSync image transmission module used in drones

Finally, we chose a straight area of ​​about 2 kilometers along the river, with a certain slope and curvature, to test how far the image transmitter can transmit in such an environment. Before transmission, we set up the image transmitter at a height of 1.8 meters and replaced the high-gain antenna to make the transmission performance more stable.

High gain antenna

From the video below, we can see that the image transmission is very stable within the visible range of 2.1 kilometers. When going down the steep slope, the signal will be interfered to a certain extent . At the same time, the base station and signal in the forward section are more complicated, and the image is interrupted. Although this is a big difference from the 6-kilometer data, due to environmental factors, it is impossible to conduct an interference-free and barrier-free 6-kilometer extreme test.

 

In fact, in the application of image transmission, there are still few application scenarios beyond line of sight . We believe that stable transmission at 2 kilometers, even if there is interference, will not affect the picture, which can cope with most use scenarios. In fact, people have no idea about such distance. Here is an example. The Beijing Bird's Nest Stadium should be a relatively large building in traditional concepts, but in fact its construction area is only 333 meters long and 296 meters wide.

Choose a good antenna and the image transmission will go far

002 Delay test

Before conducting a delay test, a little knowledge is needed, that is, zero delay in image transmission actually only exists in the laboratory . In actual use, the delay of the HDMI cable, the encoding and decoding delay of the video input and output will be added to the overall delay test, which means that there is actually no so-called zero-delay image transmission , only the concept of end-to-end low delay as much as possible . In normal use, as long as the delay is less than 120ms, it is almost imperceptible to the human eye, and such a delay will not affect the focus control of the focus puller and the rise and fall of the photographer's shooting picture.

 

Latency Test

This image transmission has certain advantages in delay testing. Unlike traditional receivers, it integrates reception and monitoring, which reduces the delay from image transmission to the monitor, so the perceived delay is also subtle.

Delay test single frame screenshot

From the single-frame screenshot, we can see that the delay of this image transmission is very small, at about 100ms . In fact, it is difficult for us to detect its delay during use, so such a product will not affect the operation whether it is used for focus tracking or shooting.

 

003 Endurance Test

When using the image transmission, you don't need to worry about the battery life, because you usually replace the battery to achieve continuous operation, but the length of the battery life can determine the frequency of replacement. Under the premise of being fully charged, the transmitter and the receiver are in working state at the same time, and the battery life can be achieved for about 3 hours. The receiver will show that the battery is too low, and after about 15 minutes, the device will completely shut down.

In addition to the built-in battery, DC power supply can also extend the battery life. However, after using it with RS3 PRO, we found that its 11W power consumption is still relatively high. When the stabilizer is fully charged, it will have 60% of the power left after working for half an hour, and it needs to be recharged after an hour. In actual use, shooting with the stabilizer can only be used for shooting some shots and cannot be used for a long time.

 

Overview

 

DJI Image Transmission is more than just image transmission. In fact, it is the core of the Ronin ecosystem and plays a connecting role. In terms of image transmission, it can stably transmit the image from the camera to the director's monitor ; in terms of control, the professional somatosensory controller and master wheel can bring an efficient and reliable control experience .

 

We also expect DJI to add more linkages to the image transmission system in the future, such as matching the image transmission on drones and completely connecting ground-to-ground and ground-to-air.

 

advantage:

1. Long transmission distance and high stability

2. Excellent screen performance at the receiving end

3. Perfect cooperation with Ruying ecosystem

 

shortcoming:

1. When using the stabilizer to power the device, the power consumption is obvious, and an external power supply solution is required.