Comparison Canon XA15 vs Canon XH A1

The type of primary media used by the camera to store captured video/photo.

— Flash (memory card). One of the most popular types of storages in modern electronics, it is widely used in camcorders of all types (see above). The flash technology itself is notable for its high speed, economical power consumption, reliability and shock resistance (due to the absence of moving parts), as well as the small size and weight of storages with their high capacity. At the same time, such memory is quite expensive. Therefore, camcorders most often use removable flash media in the form of memory cards of various types (see “Memory card support”): this allows the user to choose the best option in terms of price/capacity ratio. Another advantage of plug-in modules is the ability to read data from a memory card on another device — for example, a laptop; this greatly simplifies the exchange of footage. And when the card is full, it is enough to replace it with another one — and you can continue shooting. Note that some cameras also have built-in flash-memory blocks (see "Built-in memory"), but the ability to work with cards is usually provided even in such cases.

— HDD. Built-in hard disk drive — similar to those used for computers. Of course, the size and weight of such discs in camcorders is noticeably smaller, however, all the main features are the same. So, in terms of 1 GB of volume, they are much cheap...er than flash modules (see above), so they are well suited for creating devices with large volumes of internal memory. On the other hand, HDDs are noticeably heavier, they are sensitive to shocks and drops, they work a little slower, and they consume more energy — after all, during operation, the disk must rotate at a constant speed. In addition, such drives are built-in by definition and have all the corresponding disadvantages — in particular, when the memory is full, you will either have to sacrifice some materials or look for an opportunity to copy them somewhere. To compensate for this shortcoming, many "disk" cameras also provide slots for memory cards; but the HDD is still considered the main carrier .

— SSD. SSD solid state drives are similar to the memory cards described above in their main specifications: they are compact, reliable, resistant to shocks and drops, and have high speed. At the same time, the built-in storages usually works faster than a removable card, and its volume can be comparable to the HDD (see above). The main disadvantage of this option is the high price. In addition, all SSDs have a limit on the number of rewriting cycles, and when the resource is running out, the drive may become unwritable. On the other hand, this number can even now amount to tens of thousands of cycles, various tricks are used to increase the service life, and the technology is constantly being improved — there are promising designs in which this drawback has been completely eliminated.

— DVD. The DVD optical discs used in camcorders are smaller than standard discs — a full-size drive would simply not fit into a compact camera. The volume of such media is also reduced, for a conventional single-layer disc it is 1.4 GB. However, mini-DVDs can be read without problems in almost all DVD drives, which is one of the main advantages of such media: you can immediately view a disc from a camera on a computer or even a household DVD player. Also empty DVD are relatively inexpensive. On the other hand, they seriously lose to memory cards in terms of volume and dimensions, and an accidental scratch on the surface can make such a disc unreadable. In addition, most sold blank DVDs are for one time use, while rewritable ones are rarer and more expensive. As a result of all this, this media format is considered obsolete today and is gradually being replaced by more advanced technologies.

— MiniDV (cassette). MiniDV cassettes work on the principle of recording information in digital format on magnetic tape. On the one hand, such media are more bulky than memory cards, and besides, they require the use of complex tape transport mechanisms, which affects the dimensions, price, and power consumption of the cameras themselves. Also working with recorded materials is more difficult — because of the need to rewind the tape to access each individual fragment. At the same time, the recording format provides both good video quality and some advanced features — in particular, it is convenient when rewriting to film. As a result of all this, miniDV cassettes are practically not found among amateur cameras (see "Features"), but they are quite popular in professional models.

The technology by which the photosensitive element of the camera is made.

— CCD. Abbreviation for Charge-Coupled Device. Historically, the first type of sensor used in digital video cameras is widely used today. CCD sensors in general have high specifications, but their cost is quite high; in addition, they do not cope well with some specific conditions — in particular, point sources of light — which requires the use of various tricks and also affects the cost of the camera.

— CMOS. Abbreviation for Complementary Metal-Oxide-Semiconductor. Initially, such sensors were used as a cheaper (and lower quality) alternative to CCD, but the gradual improvement of technology has practically eliminated the gap in quality — the specifications of modern CMOS sensors allow them to be used even in professional video cameras (see "Features"). The main advantages of this technology are ease of production and lower cost, and among the disadvantages, one can only name a slightly increased tendency to heat and the appearance of corresponding noise.

It is worth saying that the real quality of the “image” from a particular camera today is more related to the size of the sensor, the specifications of the optics and processor, the shooting format and other parameters, and very little depends on the technology of the sensor.

The number of individual light sensors installed in the camera. In our catalog, this parameter is indicated only for models that have more than one sensor.

There are two main varieties of multi-sensor cameras. The first is professional models that carry three sensors on board. Each of them works with only one colour, which allows you to get an image with good clarity and high colour accuracy. Of course, the actual quality of the "picture" largely depends on a number of other parameters, but initially a three-sensor scheme provides better image quality than a single-sensor one.

The second option is 3D camcorders (see "Features"), in which two sensors can be installed — each for its own video channel. See "3D" for more details.

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.

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.

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.

An image stabilization method provided in the design of a video camera. The stabilization function itself is designed to compensate for small camera shakes so that they are not noticeable in the image. This is especially true when shooting handheld, and in fact most modern models are designed specifically for such usage. According to the method of work, there are such options:

— Optical. A special mechanism with a system of gyroscopes and movable lenses, installed directly in the lens, is responsible for the operation of such stabilization systems. It introduces a correction for all tremors, vibrations, etc., and the “picture” falls on the already stabilized sensor. Optical systems are considered the most advanced and efficient, because. their work allows you to use the entire area of the sensor, fully exploit its capabilities and provide good image quality. Among the shortcomings, it is worth noting the increase in the cost and weight of the cameras, as well as a slight decrease in the reliability of the optics. At the same time, these moments are most often not critical, and stabilizers of this type can be used even in simple and inexpensive models.

— Electronic. Electronic stabilization is carried out due to the fact that not the entire area of the sensor, but only some of it, is involved in the formation of an image for a frame. Simply put, the camera electronics "takes into account" a certain area of the sensor and...transfers the image from it into the frame; and at small displacements, this "area of attention" is also displaced, due to which the visible image remains motionless. The advantages of electronic systems are simplicity of design, lightness, compactness and high reliability; they can be used with even the simplest lenses installed in pocket cameras (see “Features”). Their main disadvantage is the need to reserve a part of the sensor, which reduces the size and resolution of the actually involved area and adversely affects the image quality.

— Optical / electronic. In such systems, both the methods described above are used — both the mechanism in the lens and the reserve on the sensor. This provides extremely high vibration compensation efficiency — the image remains stable even in such conditions in which any single method would be useless. On the other hand, the disadvantages of both options also remain relevant, and the cost of cameras with this feature is quite high.