Comparison Panasonic HC-VXF990 vs Panasonic HC-V770

The total number of individual photosensitive points (pixels) provided in the design of the sensor (1 megapixel corresponds to a million pixels). This parameter takes into account both those points on which the light falls, and service points that are not directly involved in the construction of the image. Therefore, in modern video cameras, it is more of a reference than practically significant; the actual image quality depends primarily on the number of effective megapixels (see below).

The number of light sensitive pixels directly involved in the construction of the image. These are the dots on which the “image” projected by the lens onto the matrix falls. In addition to them, there are also service pixels that are not illuminated during camera operation — they provide auxiliary information necessary for processing the resulting image. Also, when calculating effective megapixels, the reserve area required for electronic stabilization is usually not taken into account (see "Image Stabilization").

The value of the number of effective pixels for different modes of operation of the camcorder will also be different. For example, when recording video, many cameras use multiple pixels to build a single dot on the image; this is due to the fact that the sensor resolutions significantly exceed those required for video shooting (for example, the Full HD standard technically corresponds to only 2.07 megapixels). As a result, the image quality depends more on the sensor size (see above) than on the resolution. And among sensors of the same size, high resolution allows user to get better colour rendering and higher clarity (however, not always — a lot also depends on the peculiarities of image processing). If we are talking about photography, then more megapixels means a higher resolution of the resulting image, but the quality of such a picture can be relatively low due to the increased noise level and low sensitivity of each individual pixel.

Focal length of a standard video camera lens in terms of a 35 mm full-frame sensor. This parameter is also called the "equivalent focal length" — EFL.

The focal length itself is the distance from the optical centre of the lens (when focus to infinity) to the sensor, at which the sharpest image is obtained on the sensor. It is one of the key characteristics of any lens, because. determines the viewing angles, the degree of approximation and, accordingly, the specifics of the use of optics. At the same time, it is impossible to compare different options in terms of the actual focal length: the laws of physics are such that with different sizes of sensors, the same focal length will give different viewing angles. Therefore, EFL was adopted as a universal characteristic and criterion for comparison. It can be described as the focal length that a 35mm lens with the same viewing angles would have.

The larger the focal length, the narrower the viewing angle will be and the higher the degree of approximation of the visible scene. Optics with EFL up to 18 mm belongs to the class of ultra wide-angle ("fisheye") and is used primarily to create artistic effects. Distances up to 40 mm correspond to "wide angles", 50 mm gives the same degree of approximation as that of the naked eye, the range of 70-100 mm is considered optimal for portrait shooting, and large values allow the use of optics already as a telephoto lens. Knowing these provisions, one can approximately...evaluate the capabilities of the lens and its suitability for certain tasks; there are more detailed recommendations, they are described in special sources.

Also note that modern video cameras are usually equipped with lenses with a variable focal length (zoom), which allows you to change the degree of approximation and viewing angle; see "Optical Zoom" for details.

The maximum video resolution that the camera can capture. Resolution is the size of an image in points (pixels); usually it is written in two numbers, which correspond to the number of pixels horizontally and vertically.

The more pixels in the image — the clearer it is, the better you can see small details on it, however, the size of the video files increases accordingly. In addition, it is worth considering that in order to fully view the footage, you will need a screen of the appropriate resolution — otherwise all the advantages of the image will be negated. And this parameter also significantly affects the price of the device.

The smallest maximum resolution found in modern camcorders is about 720x480; the quality of such a "picture" can be compared with analogue television broadcasting. Resolution 1280x720 corresponds to the HD standard, it can be found among inexpensive TVs and monitors, and 1920x1080 (Full HD) is the most popular option among mid-range and top-class video devices. The maximum resolution used in modern consumer electronics (including camcorders) is 4K, 4096x2160; it is typical for the most advanced devices.

The vast majority of cameras are able to work not only with the maximum resolution, but also with several “more modest” options — for those cases where small file volumes are more important than high resolution.

Video file formats that the camera can use to store recorded footage. If you want to view these materials using a separate device (player, media centre, etc.), you should make sure that this player supports the appropriate formats, otherwise conversion may be necessary.

The data transfer speed provided by the camera when recording video. This parameter is also called bitrate (i.e., the number of bits per unit of time). For any file format used for recording, the general rule is that the higher the bitrate, the better the image quality (especially for formats that use lossy compression). On the other hand, high speed have appropriate requirements for the capabilities of the memory cards used — for more details, see "Memory card support"; and it increases the size of the file accordingly. Therefore, many modern camcorders are able to work with different bitrates; this allows you to choose the best option depending on what is more important for you at the moment — maximum quality or the ability to work with a slow card.

At the same time, we note that in terms of quality, this parameter is important mainly for professional video shooting. If you need a camera for amateur purposes, there is no need to look for the maximum bitrate: after all, such models (and memory cards for them) cost accordingly.

The range of shutter speeds in which the camera is capable of operating during the shooting process.

Initially, shutter speed is the time during which light affects the photosensitive material (film) when shooting a single frame. For digital sensors, this is the period of time during which an image is read from the sensor to build a separate frame. When shooting video, this interval cannot be more than 1/n, where n is the frame rate (see above), but it can be less — for example, shooting at a frame rate of 30 fps and shutter speed of each frame 1/60 s. There are no such restrictions for the photo mode.

Long exposures are good because they allow the sensor to take in more light — accordingly, the “picture” is brighter, which is especially important in low light. At the same time, they increase the likelihood of getting a blurry image — due to the rapid movement of objects in the frame, the operator's hand shaking and other random camera movements that even the stabilization system is unable to compensate for. This effect can be useful for artistic motion blur, especially when shooting video, but in photo mode it is most often undesirable. Fast shutter speeds, on the other hand, allow you to get clear shots, but with less light, and in the case of video, even with the effect of sharp, jerky movements.

Accordingly, different exposure time options will be optimal for each situation, and the wider their range, the more opportunities the came...ra has to adjust to specific conditions.

Presets and white balance adjustment modes provided by the camera.

White balance is a characteristic that describes the qualities of the lighting of the scene and the distortion that this lighting introduces into the colours perceived by the camera. Its used because modern digital sensors are unable to independently adjust to different light sources, as the human eye does. In fact, this means that the same object shot under lighting with different colour temperatures (for example, under a “warm” incandescent lamp and a “cold” fluorescent lamp) will look different without adjustment. To avoid this, the white balance setting is applied.

The main options for such a setting used in modern cameras are as follows:

— Auto. In accordance with the name, in this mode, the camera electronics independently evaluates the specifics of the illumination of the scene being shot and makes appropriate corrections to the colour reproduction. This adjustment is the most convenient for the operator, because. does not require any additional actions from him — everything is done by automation. At the same time, no such adjustment system is perfect, and does not always provide 100% white balance for the current situation. Therefore, even in the simplest models like pocket ones (see "Features"), this option is rarely the only one, not to mention professional equipment.

— Presets. The ability to select white balance from several options that correspond to...standard shooting conditions — for example, “sunny day”, “cloudy”, “fluorescent lamp”, “incandescent lamp”, etc. Such a system is quite simple even for inexperienced users and at the same time quite reliable and versatile, although its specific capabilities directly depend on the number of presets.

— Manual. Manual white balance setting assumes that the operator himself “tells” the camera which object to consider pure white — based on this, the electronics calculate the lighting characteristics (unlike automatic mode, when the reference object is also determined without user involvement). The easiest way to do this is to use a regular sheet of paper, but the procedure also works with neutral grey objects. Manual mode allows you to very accurately set the white balance for a particular scene, but it requires some time and appropriate skills — and therefore is used mainly in professional camcorders.

— Temperature control. This function allows you to set a specific value for the colour temperature of the light source (in kelvins) — it is this temperature that will correspond to the white balance when shooting. This setup format is faster and more convenient than manual setup, but is not widely used. This is due to the fact that it is well suited only for studio conditions, where the characteristics of each light source are precisely known — in other cases, manual adjustment is usually more reliable.

The format in which the camera records sound during video recording. Typically, this section indicates the number of channels and the sound system used, the file format, or the characteristics of the audio stream, such as "2ch Dolby Digital (AC-3)" or "PCM, 16bit 48kHz, 2ch". In order not to go into technical details, we note that two channels are the minimum required for surround sound (stereo), and advanced models can work with multi-channel sound like 5.1. As for other specifications, you should pay attention to them when choosing a professional device (see "Features") — in amateur and especially pocket cameras, the sound format does not play a special role. Specific features of various formats are described in special sources.