Comparison Sony A9 II body vs Sony A7r IV 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.

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.

No AA filter in camera design.

The AA filter is responsible for "anti-aliasing" — the elimination of the moiré effect. This effect can occur when shooting objects with a lot of thin horizontal or near-horizontal lines (for example, a brick wall at a great distance, or a suit made of a certain type of fabric). It leads to the appearance of a characteristic pattern in the picture, which, usually, is inappropriate; to eliminate this phenomenon, an AA filter is provided. At the same time, this feature is said to reduce the overall sharpness of the image; therefore, it may not be available in some cameras. These are mainly professional models: the absence of an AA filter gives the photographer additional features, but puts forward increased requirements for shooting skills.

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.

The number of focus points (autofocus) provided in the design of the camera.

The focus point is the point (more precisely, a small area) in the frame from which the autofocus system reads data for focusing. The simplest systems work with a single point, but their capabilities are very limited, and this option is practically not found today. Modern digital cameras have at least three focus sensors, and in the most advanced models this figure can reach several dozen.

The more autofocus sensors there are in the camera, the more advanced its autofocus capabilities will be, the more specific techniques it allows you to use. In this case, the selection of specific points used can be carried out both automatically, simultaneously with the choice of the subject program, and manually (however, the second option is more typical for professional cameras). In addition, the abundance of focus points has a positive effect on the quality of the tracking autofocus (see "Autofocus Modes").

In general, more focus sensors are generally considered a sign of a more advanced camera; however, differences in quality become really noticeable only if the difference in the number of points is significant - for example, if we compare models with 9 and 39 points. A lot also depends on the location of the points in the frame - it is believed that sensors distributed over a wide area work better than densely located in the center of the frame, even if their number is the same.

The presence in the design of the camera of the function of adjusting the front / back focus.

"Front / back focus" (or simply "back focus") is the phenomenon when the autofocus system malfunctions and "misses" the desired object — despite the fact that this object was clearly visible in the viewfinder or on the screen. This phenomenon occurs due to a mismatch between the sighting system and the survey system; it can ruin a picture, especially when working with a shallow depth of field. Front / back focus is primarily affected by cameras with interchangeable lenses (see "Camera type"), because lenses (even "native", not to mention third-party products) can initially be poorly configured. Adjusting the front / back allows you to correct the parameters of such optics using the camera itself and do without replacing the lens.