Comparison SJCAM SJ8 Air vs SJCAM SJ7 Star

The presence of a 1/4" threaded socket on the camera body. It is this size that is standard for modern tripods and is used in most of these devices. So this feature allows you to mount the camera on a tripod without using adapters and other additional equipment.

The degree of dust and water protection of the protective case supplied with the camera.

Protected case will save your camera from dust, water, temperature changes, shocks, etc. The specific degree of protection is indicated according to the international IP (Ingress Protection Rating) system, according to which each device is assigned a code of the form IPXX, where X is replaced by specific numbers. The first of them characterizes the protection against the penetration of foreign objects (from 0 to 6, where 0 is no protection). Usually, in boxes for action cameras, this indicator does not go below 5, because otherwise the container would have too large gaps, and its use simply would not make sense. Level 5 provides dust resistance — dust can get inside the case, but in small quantities that do not affect the device inside. Level 6 corresponds to complete imperviousness to dust.

The second digit is protection against liquid ingress (from 0 to 8, where 0 is no protection). Usually, the minimum level of protection against water is 6.

6 — protection against short-term immersion (for example, falling into a sea wave);
7 — protection against temporary immersion under water (up to 30 minutes) to a shallow depth (up to 1 metre), without continuous operation in immersed mode;
8 — protection against immersion to a depth of more than 1 metre for a time of more than 30 m, with the possibility of continuous...operation underwater. The specific level of protection of level 8 can be quite impressive — up to the possibility of diving to several tens of metres.

Note that protective cases for action cameras can be sold separately. Therefore, if the capabilities of the complete container do not suit you, there may be a more secure case on the market. On the other hand, in general, it is still more convenient to buy such an accessory immediately with a camera — so as not to waste time and effort on choosing the right protective 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.

Frame rate supported by the camera when shooting in slow motion.

In general, such shooting is called “high-speed” because it is carried out at an increased frame rate (more than 60 fps). As a result, when played back at normal speed (60 fps and below), the video looks slow hence the name. This kind of slow-motion can be used just for fun, as an artistic technique, and even for scientific purposes — to capture movement that is too fast for the human eye. In any case, the higher the slow-mo frame rate, the more you can slow down the video and the more advanced the camera is in this regard. On the other hand, the higher the frame rate, the more performant the graphics part should be; and this, in turn, affects the price of the device, sometimes quite noticeably.

We also note that slow-mo shooting may be available only at certain resolutions, not always at maximum. These points can be directly specified in the specs of the action camera.

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.