Comparison Axnen H9 4K vs SJCAM SJ4000

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 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.

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.

Additional information regarding the sensor installed in the lens. This item can specify both the diagonal size (in inches) and the sensor model, and sometimes both parameters at once. Anyway, such data is provided only if the device is equipped with a high-class image sensor. With the model, everything is quite simple: knowing the name of the sensor, you can find detailed data on it.

The diagonal of the image sensor is traditionally indicated in fractions of an inch — accordingly, for example, a 1/2.3" sensor will be larger than 1/2.6". Larger sensors are considered more advanced, as they allow for better image quality at the same resolution. This is because due to the larger sensor area, each pixel is also larger and receives more light, which improves sensitivity and reduces noise. Of course, the actual image quality will also depend on several other parameters, but in general, a larger sensor size usually means a more advanced camera.

The maximum resolution at which the action camera can take photos. Specified in pixels horizontally and vertically.

This parameter is directly related to the resolution of the image sensor(see above): the total number of pixels in the photo, usually, corresponds to the number of pixels in the sensor. For example, a photo resolution of 4608x3456 corresponds to a sensor of 15925248 pixels, or approximately 16 megapixels. If the number of pixels in the photo is greater than the claimed resolution of the sensor, then the manufacturer uses software tricks that allow you to improve the photo resolution to a higher one than originally. This reduces the cost of devices but also affects the quality of images.

Theoretically, high-resolution images can provide good detail, but in fact, much depends on the specs of the sensor (primarily physical size) and image processing features.

— Photo during video. The ability to take photos directly while recording a video — usually using a separate button. Thus, it is convenient to fix the most significant moments of what is happening. Such photos are much better in quality than "freeze frames" from the captured video.

— Serial photo shoot. This feature allows you to take several pictures at once in a short period (usually it is a fraction of a second). A series of shots increases the chance of capturing a good moment, which can be very important given the specifics of using action cameras.

— One click recording. The ability to quickly turn on the camera for recording — literally at the touch of a button, by the name. Moreover, such a button works even if the device is turned off. However, the recording inevitably starts with some delay; but often this delay is a fraction of a second.

— Online streaming. Ability to stream video to popular services like YouTube and social networks (Facebook, Instagram, TikTok, etc.). Usually, the online streaming function is implemented when the action camera is connected to the Internet via a Wi-Fi network, less often via a wired connection. Communication with the World Wide Web can be held directly or through a smartphone or computer. It will require the use of appropriate software.

— Time lapse. A special mode of operation of the action camera, in which video recording is carried out at a slower frequency is mainly used for filming slow processes. Thus, for example, a long journey or a long sunset can fit into a 3-minute video.

— Auto-rotate. The function of automatic rotation of the captured photos and videos to the position corresponding to the position of the camera. Without this feature, all footage during playback would be displayed strictly in landscape orientation, and footage shot with the camera upside down or upside down would have to be rotated in a photo or video editor. Usually, at the beginning of video recording, auto-rotation is blocked — so that the position of the frame at any time corresponds to the rotation of the camera itself relative to its original position.

— Photo panoramas shooting. The ability to use the camera to take panoramic photos. In traditional action cameras (see "Product type"), such shooting is carried out as follows: the camera takes several separate photos, which are then glued into one image. Regarding panoramic and 360-degree models (see ibid.), it is worth noting that not all such models support shooting in panoramic format, so it is advisable to check the availability of this function separately.

— Key points labels. The ability to add special marks to the footage that indicate key moments. While viewing such videos, you can go directly to the labels — this is easier than manually searching for the right moment. This feature is especially useful when shooting long videos, as well as when numerous individual files. The label, usually, is placed right during the shooting by pressing a special button or by voice command.

— Night shooting. Special mode for recording in low light conditions. The specific implementation of this function may be different: in some models, the sensitivity of the sensor is increased, in others, shooting in the IR range is used. Accordingly, specific features may vary: not every camera with this function can shoot in complete darkness, and these nuances should be clarified separately.