Comparison Sony HDR-CX450 vs Sony HDR-CX625

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 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.

The highest frame rate provided by the camera when shooting video. The minimum frequency for normal viewing is the classic 24 fps used in cinema. At the same time, most modern video cameras are capable of providing up to 50 – 60 fps, and even higher frequencies can be used for the slow motion effect.

In fact, this indicator is important primarily when shooting dynamic scenes. The higher the frame rate, the smoother the fast motion will look in the frame, the less jerky it will be and the more pleasant the overall impression of the image will be. The reverse side of this is an increase in the size of recorded files (all other things being equal). Therefore, the frame rate can be made adjustable so that the operator can choose the best option for a particular situation.

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.

Memory cards types supported by the camcorder. In modern devices, there may be such options:

— SD (SDHC, SDXC). The most popular memory card format for various electronics, including camcorders. The original SD standard allows you to create storages up to 4 GB, the next SDHC — up to 32 GB, and its successor SDXC — up to 2 TB. Reading devices under a certain standard are compatible with earlier versions of cards, but not vice versa: for example, a camera with SD HC support will be able to work with regular SD, but not with SD XC. These types of cards may correspond to different speed classes. These classes are described in more detail in special sources, but here we note that class 4 is considered the minimum suitable option for recording Full HD video. And anyway, the speed of the card should not be lower than the video recording speed provided by the video camera (see above) — otherwise the device just can't function properly. It is also worth mentioning that the rather large size of SD cards (32x24 mm) makes it difficult to use them in portable devices; to solve the problem, the microSD standard appeared (see below).

— microSD. in internal design such cards are completely similar to the SD cards described above and differ from them only in their reduced size — 15x11 mm. This allows them to be used even in the most compact modern devices, however, with equal volume, such cards are more expensive than their full-size counterparts, and the size of m...ost modern camcorders allow the use of conventional SD. Therefore, this option is found only where compact size is crucial — primarily among pocket models (see "Features"). microSD cards also have HC and XC modifications and are divided into speed classes; they can be used in SD card readers using the simplest adapters, and sometimes without them at all.

— MMC. A standard similar in many respects to SD — up to the fact that such cards are fully compatible with SD card readers in terms of size and contacts. MMC capacity — up to 64 GB, however, they work a little slower. Because of this, this standard is practically not used “in its pure form”, its support is usually combined with support for the more popular SD.

— MS (Memory Stick). The standard created by Sony is used mainly in the technology of this company, including camcorders. There are many varieties of such media, and not all of them are mutually compatible. MS cards are quite expensive and not as versatile as SD cards, so many cameras that support them can also work with SD.

— CompactFlash (CF). A standard originally created for professional photography; among video cameras, it is also used in professional models (see "Features"). CF cards have a good capacity (up to 128 GB) and high speed; their main disadvantage is their large size, which limits their use in compact technology. There are two CF formats — Type I and Type II; cards of the second type are faster, but do not fit the card readers of the first type due to their greater thickness.

— SxS. The standard, created by Sony and SanDisk specifically for professional camcorders and film cameras, is used in top-class devices. Such cards have high speed of work due to the fact that they use the connection according to the PCI Express standard; and their shape allows to install them directly into the ExpressCard slot on a computer or laptop. The maximum capacity of such media is 32 GB.

— P2. A company standard created by Panasonic exclusively for professional video recording. Inside, the P2 card is an array of 4 SD storages, and externally it is identical to a PCMCIA computer card and can be installed directly into the appropriate slot. The volume of such media is up to 64 GB.