Number of megapixels
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).
Effective megapixels
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 (35mm equivalent)
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.
Aperture
Aperture of a standard video camera lens.
This parameter describes how much the lens attenuates the light output. Usually it is written as a ratio between the diameter of the active hole and the focal length of the lens, while the first value is taken as one and denoted as f — for example, f/1.8 or f/5.6. Moreover, the smaller the number in such a record, the higher the aperture ratio: for example, in our example, the first option is “lighter” than the second. Also note that most lenses with a variable focal length (see above) also have a variable aperture — in such cases it is indicated by the range from maximum to minimum (from a smaller number to a larger one).
A high aperture ratio is important primarily when shooting in low light conditions: it allows you to capture an image without “lifting up” the sensor sensitivity and without creating additional artifacts in the form of noise, and in the photo shooting mode, you can also work with shorter shutter speeds (which is useful for dynamic scenes). In addition, the higher the aperture, the lower the depth of field and the easier it is to get a blurry background. Note that for simple everyday tasks this parameter does not play a decisive role, but in professional shooting it can be very significant.
Recording formats
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.
Night shooting
The camera has
night mode. In this case, both the meaning of this parameter and its specific implementation can significantly differ from model to model. So, in some cameras, this term means a special mode for deep twilight, which allows you to get a relatively reliable colour reproduction (“as in the daytime”) without the use of additional illumination. Others use an infrared filter, due to which shooting can be done even in complete darkness — but the image will turn out to be black and white. And in the most advanced models, this filter is complemented by its own IR illumination system, which further expands the capabilities of the camera.
Thus, the details of the operation of this mode in a particular camera should be clarified according to the official documents of the manufacturer. However, anyway, if you often have to shoot in low light conditions or at night, it may make sense to pay attention to such cameras. Also note that the presence of a
standart backlight lamp (see "Features") is not considered a night shooting feature, although it can also significantly "make life easier" in the dark.
Auto exposure
The number of auto exposure modes (scene programs) provided in the camera design.
Exposure is a certain combination of the main shooting parameters — shutter speed, aperture and sensor sensitivity. Different situations may require different combinations to obtain the best image quality. For example, for shooting dynamic scenes, relatively fast shutter speeds are required to avoid blurring each frame — and for normal illumination of each frame, you need to open the aperture or increase the sensitivity. In portrait shooting, the conditions are dictated by the aperture, etc. Auto exposure makes it much easier to set all the parameters mentioned — instead of selecting a combination manually, the operator just needs to turn on a certain scene programme on the camera.
The more auto exposure modes, the more extensive the camera's ability to adjust to a specific situation, the easier it is to work with it under a wide variety of shooting conditions. At the same time, it is worth noting that when calculating these modes, our catalog takes into account not only automated presets (“portrait”, “beach”, “sunset”, etc.), but also “full automatic”, when the camera itself determines the specifics of the scene, and a fully manual setting mode.
Scene programmes
A list of scene programs (also known as auto exposure modes) provided in the camera design. See "Auto exposure" for details on the meaning of these programs.
Number of megapixels
Effective resolution of the camera sensor when working in the photo shooting mode; in other words, the number of points or pixels that are directly involved in this mode (1 megapixel corresponds to a million points). The maximum size of a photo (see below) directly depends on this parameter: in fact, the number of megapixels corresponds to the size of the image vertically and horizontally, multiplied by each other. For example, a resolution of 3264x2456 corresponds to 8,016,384 pixels, or approximately 8.02 megapixels.
As with traditional digital photography, numerous megapixels allows you to get more detailed images with better visibility of fine details. However, as the resolution increases with the same sensor size, the size of each individual pixel and the amount of light falling on it decrease, which increases the likelihood of noise and generally reduces the quality of the picture.