What is the reference significance of DxOMark for camera image sensor and lens scoring?

1. DXO is a laboratory located in Paris, France. It is also a third-party organization to evaluate the quality of camera sensors and lens quality. At present, it is the most authoritative organization to evaluate sensors, and there is no one. The same as DXO is the German DPReview Laboratory. DP evaluates the overall performance of the camera, with different emphasis from appearance to image quality to control.

2. DXO evaluation sensor mainly involves three indicators, one is color depth, the other is moving too much, and the third is high sensitivity;

3. Color depth of sensor. This index is used to measure how many different colors a camera can distinguish. Usually, if the red, green and blue channels of RAW are 12 bits each, the final distinguishable color is 36 bits, but in fact, due to the chip performance, noise and color space conversion problems, the actual resolution of each channel can only reach 8 bits, which means that the total ***24-bit color category is already outstanding. In actual shooting, the color depth reflects the sense of color layering. If the evaluation result of color depth is poor, some colors of the photo will appear faults. This will be felt when the photo is enlarged, which is generally negligible for display viewing. Color depth has a great influence on professional photography, which can be ignored by family users;

4. Dynamic range of sensor. Dynamic range index is used to measure the camera's ability to record details from bright to dark. Theoretically, the wider the dynamic is, the better the tolerance is. The highlight of the camera is not easy to die white, and the dark part is easy to die white. The high-dynamic camera can capture the imaging details in the highlight or dark light, which is basically uncontroversial. In fact, DXO is not enough to evaluate the tolerance of Canon camera sensors, and Canon cameras also reflect the phenomenon that the highlight is easy to die white in real shooting. However, in the dynamic range indicators of digital cameras released by DXO, many SLR cameras are above the dynamic range of 11th and 12th gears, and some cameras even have the dynamic range of 13th or even 14th gears. What is the concept of 14-speed light ratio? Sunny day is about 1, to 2lux illumination, full moon night is about 1lux illumination, and 14th gear is equal to 16,384 times light ratio, so it is roughly the illumination contrast between sunny day and full moon night. Obviously, it is possible to record the details of sunny day and full moon at the same time in one shot, and none of the real shots can do it. Many camera players have doubts about this, and I also have doubts. Therefore, DXO's dynamic evaluation has certain reference significance for both professional players and home users, but it has no absolute reference;

5. The sensor has high sensitivity. As the name implies, the available high sensitivity is the level of camera high sensitivity, and its core is the level of signal-to-noise ratio. The output signal-to-noise ratio measurement method used by DXO is to measure the camera output image (in the RAW file) in an area with uniform illumination. The average gray value of each pixel in this area is taken as the signal, and the standard deviation of the gray value of each pixel relative to the average value is taken as the noise. The ratio of the two is the signal-to-noise ratio SNR corresponding to this gray value. Then it is converted to decibel (dB) in the above way. DXO evaluation of available high sense is basically scientific and has great reference significance. However, due to the progress of science and technology, some camera sensors include digital noise reduction processing specifically for dark parts, which can improve the noise performance of dark parts without affecting the resolution, such as Sony Corporation, which develops sensors. In this case, the data measured by DXO can't fully reflect the real ability of the sensor. After all, noise reduction by software post-processing can also improve the image quality of the dark part. But on the whole, DXO is of great reference significance to the evaluation of high sensitivity, and the actual shooting can also reflect the evaluation of DXO;