Comparison Sony FDR-AX700 vs Sony FDR-AX100E

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 degree (multiplicity) of zoom provided by the camcorders due to software methods, without changing the focal length of the optics (see "Optical zoom"). The key principle of such an zoom is that part of the image from the sensor is "stretched" to the entire frame. This somewhat worsens the “picture” — after all, not all effective pixels take part in its formation; and the higher the zoom, the worse the quality becomes. On the other hand, this method does not depend on the specifications of the lens and works even with the simplest lenses that do not have zoom lenses, and it is much easier to achieve high magnification than with the optical method.

In modern camcorders, there are two options for using digital zoom. So, among pocket devices (see "Features"), it may be the only available option — not all of them are equipped with zoom lenses. And in full-size models, digital zoom usually complements optical zoom and turns on after the lens reaches the limit of its capabilities.

Note that when shooting 3D (see above), this feature may not be available, and in professional models it is often not used at all.

The diameter of the mount designed to install an additional filter on a regular camera lens. Such filters can have different types and purposes: UV filtering, colour correction, polarization, artistic effects, etc.; to select them for a specific camera model, you need to know the diameter of the mount.

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 lowest illumination of the scene being shot, at which the camera is able to provide an image of normal quality. Note that in devices with a night view function (see below), this parameter can be specified in different ways. In some models, minimal illuminance is implied, in which the camera can shoot without backlight and at the same time maintain colour reproduction (as in normal daytime shooting); in others — an "absolute" minimum of light, below which it is impossible to use even the night mode. This point should be clarified according to the official documents of the manufacturer.

Anyway, the lower this indicator, the less light the camera needs to work and the better it handles with shooting at dusk or even at night. Thanks to the use of special technologies, some models are able to work even in complete darkness, with an illumination of 0 lux; this is due to the fact that modern sensors are able to perceive infrared radiation invisible to the eye. However, more often than not, shooting still requires a certain amount of light — at least tenths of a lux. For comparison: an illumination of 0.1 lux approximately corresponds to a lunar night with a “half” phase of the moon, and 1 lux is comparable to a bright full moon in southern latitudes.

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.