Inspire 2 Image Quality In-Depth Review-Part I

The Inspire 2 is marketed as a filmmaking drone. As a director and photographer who worked in the film industry for years,  I’ve learned that image quality is a professional cinematographers’ primary concern when choosing equipment. In order to find out how the Inspire 2’s image system performs, I made an in-depth review of the DJI Inspire 2’s image quality.

This is the Part 1 of review, which analyzes two dimensions: resolution and dynamic range. The next Part gives another three dimensions on color, ISO and jelly effect (Check on: Inspire 2 Image Quality In-Depth Review-Part II). It can help cinematographers and photographers gain a better understanding of this product.

Let’s look at Resolution and Dynamic Range.

1. Resolution

One of Inspire 2’s highlights is the new image processing system, CineCore 2.0. It’s able to shoot 5.2K/30fps videos in CinemaDNG by shooting 30 frames of 5280*2972 RAW photos every second, which are combined to create a 16min video that can fill a 480G hard drive.

However, not everyone can afford this format, and that’s why Inspire 2 has introduced ProRes capability, a professional, efficient coding format invented by Apple. DJI is proud that Inspire 2, like most third-party video recorders or professional cameras, has ProRes onboard.

List of recording formats

The camera of Inspire 2 is equipped with a Sony M4/3 image sensor (size: 17mm*13mm; crop factor: 2x), 12.8 stops of dynamic range and a standard MTF-mount. Currently 8 M4/3 lens have been authorized by DJI to be mounted on Inspire 2, including the standard 15mm/f1.7 lens produced by Panasonic shipped with the aircraft.

In fact, the hardware configuration of Inspire 2’s image processing system has reached the highest level among all M4/3 cameras. DJI also plans on launching a new handheld gimbal compatible with Zenmuse X5S and making it a powerful photography tool for daily use.

Below is a detailed review of Inspire 2’s camera based on a variety of different factors such as resolution, dynamic range, color expression, jelly effect, and ISO.

First we test the 5.2K resolution claimed by DJI. We use an ISO12233 2000 test chart to test this spec.

Inspire 2 during test

Below is the result of the first test. It is a frame randomly picked in a 5.2K CinemaDNG video shot by Inspire 2. The resolution of the image below is 5280*2972. Let’s have a look at it before we carry out more tests.

Resolution of Inspire 2 camera has exceeded 2000 lines

After decoding the RAW file and enlarging the image, we can see visually that the  Inspire 2 camera has exceeded the highest 2000 lines mark (red boxes) effortlessly, even though it’s just a screenshot. The result has exceeded our expectation of Inspire 2, given the fact that the best result achieved by most mainstream 4K cameras is merely about 2000 lines.

Next we take out a 4000 lines test chart, (which hasn’t been used in a while), to see exactly how many lines Inspire 2 can achieve. This chart is enough to test resolution as high as 8K, and theoretically no camera in the market can reach that limit.

Screenshot from 5.2KCinemaDNG video shot by Inspire 2

On decoding the file again we find that the details of black and white are invisible at 2500 lines. After several repetitions of software and manual analysis, we finally find the highest resolution Inspire 2 can achieve—2450 lines (±100). Comparing this result with that of common 4K cameras, it’s safe to conclude that Inspire 2 does a perfect job in resolution.

Of course, we also test the resolution of other formats. And here are the results:

4K: 2200 lines
2.7K: 1330 lines
1080P: 1090 lines

All this data shows Inspire 2’s ability to reach the highest level of quality in every format, allowing it to compete with other professional cameras in shooting top quality images and videos. Compare the Inspire 2 camera with other M4/3 cameras and we can see that DJI has maximized the performance of the CMOS sensor integrated in Inspire 2’s camera.

2. Dynamic Range

Inspire 2 offers a highest dynamic range of 12.8 stops, compared with the 13 stops threshold offered by professional movie cameras. To give readers a general impression on Inspire 2’s dynamic range, we shoot a DLOG video with Inspire 2 under the latest firmware version.

DLOG performance

With a little adjustment to the Gamma line we can see that the information of footage shot with DLOG mode has been heavily compressed, which means that there is still a large amount of room for further processing. A common scene like this is no problem for Inspire 2. DJI also optimizes its DLOG mode each time a new version of it comes out, which is why DJI hasn’t opened Inspire 2 LUT to users yet.

To quantify its dynamic range, we use Xyla 21 Dynamic Range Test Chart from DSC Labs. The test is very simple. We make sure the brightest box is not over-exposed and then count the rest of the boxes until they cannot be seen. In the current version, ISO in DLOG mode is locked to 400, hence the entire test is based on ISO 400.

Dynamic range test

There are 13 boxes that can be observed altogether, though many people can only see 11. It’s true that the 13th box has information, however, only very little. With a bit more adjustment we can see more information shown in the 13th box. The actual dynamic range may vary according to image process, coding method and other factors. Therefore, when controlling exposure, it’s the photographer’s choice to stress more on highlights or shadows.

In the review Part II, I test color, ISO and jelly effect and offer my final opinion on this drone. Check the Part II: Inspire 2 Image Quality In-Depth Review-Part II 

Thanks for Reading!

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