Comparison Sony A7 IV body vs Sony A1 body

The result shown by the camera in the DxOMark ranking.

DxOMark is one of the most popular and respected resources for expert camera testing. According to the test results, the camera receives a certain number of points; The more points, the higher the final score.

— CCD (CCD). Abbreviation for Charge-Coupled Device. In such sensors, information is read from the photosensitive element according to the “line at a time” principle — an electronic signal is output to the image processor in the form of separate lines (there is also a “frame at a time” variant). In general, such matrices have good characteristics, but they are more expensive than CMOS. In addition, they are poorly suited for some specific conditions — for example, shooting with point light sources in the frame — which is why you have to use various additional technologies in the camera, which also affect the cost.

— CMOS (CMOS). The main advantages of CMOS matrices are ease of manufacture, low cost and power consumption, more compact dimensions than those of CCDs, and the ability to transfer a number of functions (focus, exposure metering, etc.) directly to the sensor, thus reducing the dimensions of the camera. In addition, the camera processor can read the entire image from such a matrix at once (rather than line by line, as in CCD); this avoids distortion when shooting fast-moving objects. The main disadvantage of CMOS is the increased possibility of noise, especially at high ISO values.

— CMOS (CMOS) BSI. BSI is an abbreviation for the English phrase "Backside Illumination". This is the name of "inverted" CMOS sensors, the light on which does not penetrate from the side of the photodiodes, but from the back of the matrix (from the side of the subst...rate). With this implementation, the photodiodes receive more light, since it is not blocked by other elements of the image sensor. As a result, back-illuminated sensors boast high light sensitivity, which allows you to create images of better quality with less noise when shooting in low light conditions. BSI CMOS sensors require less light to properly expose a photo. In production, back-illuminated sensors are more expensive than traditional CMOS sensors.

— LiveMOS. A variety of matrices made using the technology of metal oxide semiconductors (MOS, MOS — Metal-Oxide Semiconductor). Compared to CMOS sensors, it has a simplified design, which provides less tendency to overheat and, as a result, a lower noise level. It is well suited for the "live" viewing mode (viewing in real time) of the image from the matrix on the screen or in the camera's viewfinder, which is why it received the word "Live" in the title. They also feature high data transfer rates.

The total number of individual light sensitive dots (pixels) provided in the camera's sensor. Denoted in megapixels - millions of pixels.

The total number of MPs, as a rule, is greater than the number of megapixels from which the frame is directly built (for more details, see "Effective number of MPs"). This is due to the presence of service areas on the matrix. In general, this parameter is more of a reference than practically significant: a larger total number of MPs with the same size and effective resolution means a slightly smaller size of each pixel, and, accordingly, an increased likelihood of noise (especially at high ISO values).

The number of pixels (megapixels) of the matrix directly involved in the construction of the image, in fact — the number of points from which the captured image is built. Some manufacturers, in addition to this parameter, also indicate the total number of MPs, taking into account the service areas of the matrix. However, it is the effective number of MPs that is considered the main indicator — it is this that directly affects the maximum resolution of the resulting image (see “Maximum image size”).

A megapixel is 1 million pixels. Numerous megapixels ensures high resolution of the captured photos, but is not a guarantee of high-quality images — much also depends on the size of the sensor, its light sensitivity (see the relevant glossary items), as well as hardware and software image processing tools used in the camera. Note that for small matrices, high resolution can sometimes be more of an evil than a blessing — such sensors are very prone to the appearance of noise in the image.

The maximum size of photos taken by the camera in normal (non-panoramic) mode. In fact, this paragraph indicates the highest resolution of photography — in pixels vertically and horizontally, for example, 3000x4000. This indicator directly depends on the resolution of the matrix: the number of dots in the image cannot exceed the effective number of megapixels (see above). For example, for the same 3000x4000, the matrix must have an effective resolution of at least 3000*4000 = 12 million dots, that is, 12 MP.

Theoretically, the larger the size of the photo, the more detailed the image, the more small details can be conveyed on it. At the same time, the overall image quality (including the visibility of fine details) depends not only on resolution, but also on a number of other technical and software factors; see "Effective MP number" for more details.

The sensitivity range of a digital camera matrix. In digital photography, light sensitivity is expressed in the same ISO units as in film photography; however, unlike film, the light sensitivity of the sensor in a digital camera can be changed, which gives you more options for adjusting shooting parameters. High maximum light sensitivity is important if you have to use a lens with a low aperture (see Aperture), as well as when shooting dimly lit scenes and fast-moving objects; in the latter case, high ISO allows you to use low shutter speeds, which minimizes image blur. However, note that with an increase in the value of the applied ISO, the level of noise in the resulting images also increases.

The maximum resolution and frame rate of video captured by the camera in the Ultra HD (4K) standard.

UHD 4K refers to resolutions with a frame size of approximately 4,000 horizontal pixels. Specifically, in cameras for video shooting, resolutions of 3840x2160 and 4096x2160 are most often used. Regarding the frame rate, it is worth noting first of all that a normal (not slow-motion) video is shot at a speed of up to 60 fps, and in this case, the higher the frame rate, the smoother the video will be, the less jerks will be noticeable when moving in the frame. If the frame rate is 100 fps or higher, this usually means that the camera has a slow-motion video mode.

The maximum resolution and frame rate of video taken by the camera in a standard higher than 4K.

As of the end of 2020, the situation with shooting such video with cameras is as follows. Most often we are talking about working in 6K format, at a resolution of 5952x3988 or 7680x4320, and the frame rate does not exceed 30 fps, and in many models even 24 fps. Such a shooting speed by modern standards is very low, but it is technically difficult to achieve a higher frame rate — in this case, this would require a very powerful and unreasonably expensive hardware hardware. And even at this speed, cameras with 6K support are very expensive, so there are not many of them on the market. On the other hand, these resolutions provide an extremely high level of detail.

File formats in which the camera can record video. Given that the footage is designed to be viewed on an external screen, you should make sure that the playback device (DVD player, media centre, etc.) is able to work with the appropriate formats. At the same time, many camera models themselves can play the role of a player by connecting to a TV via an audio / video output or HDMI (see the corresponding paragraphs of the glossary). And if the video materials are to be viewed on a computer, you should not pay special attention to this parameter at all: problems with format incompatibility in such cases rarely occur, but are usually solved by installing the appropriate codec.