Comparison SJCAM SJ9 Max vs Xiaomi YI 4K Plus Action Camera

The level of dust and water protection provided by the body of the camera itself. Most action cameras are designed for recording in extreme conditions, but the level of protection of each model can vary significantly — from the ability to shoot in the rain, to full tightness, allowing for a long immersion under water.

To characterize the security level of the camera, the international IP classification is used. Each device is assigned a code of the form IPXX, where instead of the first X — the level of protection against the ingress of foreign objects (including dust), and instead of the second X — the level of protection against the ingress of water.

Levels of protection against dust and foreign objects in modern action cameras are never lower than 5 — lower protection classes would provide unacceptably large gaps in the body. Specifically, level 5 provides that dust can get inside in small quantities, but does not affect the performance of the device. A higher level — 6 — provides full dustproof.

To characterize the level of protection from water, the following classification is used:

0 — no protection;
1 — drops of water falling at a right angle relative to the operating position of the device cannot cause dangerous consequences;
2 — protection against drops falling on the equipment at an angle of up to 15°;
3 — at an angle up to 60° (splash protection, minimum rain protection);
4 — protection from rai...n with strong wind;
5 — protection against water jets falling at any angle (water jets, for example, from a hose or heavy rain cannot harm the device);
6 — from temporary flooding;
7 — from temporary immersion under water to a depth of not more than 1 metre;
8 — from prolonged diving to depth (maximum time and depth are specified by the manufacturer separately).

In some cases, a model may only be IP-certified for one type of protection (only against sand or water). In this case, instead of the second parameter, simply X is put. So, for example, IPX6 security means that the camera is protected from temporary flooding and heavy rain, but the level of protection from dust is not defined and, accordingly, is not certified.

It is important to note that this parameter characterizes the protection of the camera itself, but does not take into account the capabilities of protective cases. Do not confuse it with the protection of the outer case, which sometimes comes with the device (see "Dust-, moisture-proof of case").

The ability of the camera to record HD video (720p).

The official HD specification provides a resolution of 1280x720. However, in action cameras, there may be resolutions slightly different from this parameter, for example, 1080x720 or 1440x960. Anyway, HD is the most modest of today's high-definition standards, which, nevertheless, provides a fairly clear and detailed image.

Another important parameter given in this paragraph is the frame rate. The higher it is, the smoother the movement in the frame will be, and the details in dynamic scenes will be visible clearly. Technically, 30 fps or even less is enough for video, but 60 fps is considered the perfect value — at this frame rate, motion blur becomes almost imperceptible and at the same time the size of the captured files remains within reasonable limits. However, there are cameras on the market with higher frame rates at HD resolutions — 100 fps, 120 fps, 200 fps and even 240 fps. This speed is usually used for recording slow-motion video, but such a possibility needs to be specified separately.

The ability of the camera to shoot Full HD (1080p) video.

The standard image size in this standard is 1920x1080. However, in the case of action cameras, this category also includes some other resolutions that are similar in quality, for example, 1440x1080. In general, Full HD provides a very good balance between image quality, the volume of captured files and the processing power requirements for processing them, which makes this standard very popular in modern video equipment — both in cameras and in TV monitors.

Another important parameter given in this paragraph is the frame rate. The higher it is, the smoother the movement in the frame will be, and the details in dynamic scenes will be visible clearly. Technically, 30 fps or even less is enough, but 60 fps is considered the perfect value — at this frame rate, motion blur becomes almost imperceptible and at the same time the size of the captured files remains within reasonable limits. However, there are cameras on the market with a higher frame rate at FullHD resolutions — 90 fps, 100 fps, 120 fps and even 240 fps. This speed is usually used for shooting slow-motion video, but the possibility of such shooting needs to be specified separately.

The ability of the camera to shoot QuadHD video.

This standard includes an extensive set of resolutions — from 1440 to 3456 pixels horizontally and from 1440 to 2160 pixels vertically, with almost two dozen intermediate options. It is a rather specific transitional option between the relatively inexpensive FullHD 1080p and the demanding UltraHD 4K, allowing you to shoot higher resolution video than 1080p without significantly increasing the cost of equipment. Note that pure QuadHD resolutions are rare in TVs and monitors, but modern technologies make it possible to comfortably watch videos of this format on any high-resolution screen.

Another important parameter given in this paragraph is the frame rate. The higher it is, the smoother the movement in the frame will be, and the details in dynamic scenes will be visible clearly. For example, a filming speed of 25 fps or 30 fps approximates the standard frame rate in film and television; such an image is quite viewable, but fast-moving objects in the frame will look blurry. With an increase in speed to 60 fps, this effect becomes almost imperceptible. The highest QuadHD frame rate found in modern action cameras is 120 fps; this frequency is used when shooting slow-motion video (as well as models with a frequency of 100 fps) because at a n...ormal playback speed, 60 fps is enough.

The ability of the camera to shoot Ultra HD 4K video.

This format covers several resolutions in which the horizontal frame size is approximately 4K pixels. The most popular in action cameras is 3840x2160 (twice the FullHD frame on each side), but there are other options — for example, 3840x1920, corresponding to an aspect ratio of 2:1. In general, 4K is a kind of successor to Full HD: among HD standards that surpass Full HD, UltraHD is the most popular, in particular, many advanced TVs are produced with 3840x2160 screens. On the other hand, this format is quite demanding in terms of processing power and memory, so it is relatively rare in action cameras, mainly among premium models.

Another important parameter given in this paragraph is the frame rate. The higher it is, the smoother the movement in the frame will be, and the details in dynamic scenes will be visible clearly. However, in UltraHD mode, most modern action cameras produce a very low frame rate — most often 30 fps, and in some models 24 fps or even 15 fps. This video is quite viewable, but fast movement in the frame may look blurry. There are cameras capable of shooting UltraHD at a solid speed of 60 fps — the blurring effect during such shooting is almost imperceptible. However, such a model cost is high.

For models with several lenses, as a rule, this parameter is indicated for each lens.

Most often (unless otherwise indicated), the specifications indicate the field of view by the diagonal of the frame; in some ultra-wide-angle lenses it can exceed 180°. A special case is made up of lenses for which a 360° view is declared: this means that the optics cover the entire hemisphere in front of it. Such lenses are found in panoramic and 360-degree cameras (see “Product type”).

In general, the field of view primarily determines what area of the scene is being captured into the frame. Accordingly, the wider it is, the more space the camera captures, and the lower the likelihood that something that is happening will be off-screen. On the other hand, it is worth considering that a strong increase in the field of view leads to distortions of the “picture”, especially at the edges, as well as, to a decrease in the size of visible objects and a decrease in detail. Detailed recommendations regarding choosing a camera based on this parameter can be found in special sources.

The presence of a digital (electronic) stabilization system in the camera design.

Any stabilization is intended to compensate for small juddering of the image that occurs due to the instability of the hold in the hands, vibrations from the motor or road roughness (when used in transport), etc. Digital stabilization is carried out as follows: a reserve area is allocated along the edges of the sensor, which under normal conditions does not participate in the formation of the final image. If the device is being shaken, the camera electronics select certain parts of the image from the reserve and build the image in such a way that in the end, it remains stable.

Compared to other methods of stabilization, digital systems are extremely simple and reliable. Moreover, they are inexpensive and have almost no effect on the weight, dimensions, and price of the camera. At the same time, with this method of stabilization, the effective area of the image sensor is reduced, which can adversely affect the image quality and the amount of noise on it.

The presence of an optical stabilization system in the design of the camera.

Any stabilization is intended to compensate for small juddering of the image that occurs due to the instability of the hold in the hands, vibrations from the motor or road roughness (when used in transport), etc. Optical stabilization is carried out by a system of movable lenses and gyroscopes in the camera lens; such a system monitors the vibrations of the device and adjusts the optics in such a way that the image falling on the sensor remains motionless.

The optical method is considered more advanced than the electronic method described above: it allows you to use the entire area of the image sensor, which contributes to good image quality. At the same time, the stabilization mechanism turns out to be quite complex and expensive, and often quite fragile. In addition, it increases the weight and dimensions of the entire device — not by much, but sometimes this may be important. And the miniaturization of such systems further affects the price. As a result, the presence of an optical stabilizer is most often a sign of a fairly advanced camera.

The number of built-in microphones provided in the camera.

This parameter is indicated only for models that have more than one microphone. This design provides additional capabilities, but the range of these capabilities depends on the number of microphones and the features of a particular model. So, most often such devices have two microphones; this can be a pair for recording stereo sound, or one microphone can work to record sound, and the second one can act as a sensor for the noise reduction system (see above). A larger number - 3 or 4 microphones - is found mainly in 360-degree cameras (see “Product type”), where such equipment is used to record “surround” multi-channel sound.