Brightness
The brightness of the image produced by the projector at maximum backlight brightness. Usually, the average brightness of the screen, derived from a special formula, is indicated. The higher it is, the less the image depends on ambient light: a bright projector can provide a clearly visible image even in daylight, but a dim one will require dimming. On the other hand, increasing brightness reduces contrast and accuracy of colour reproduction.
Accordingly, when choosing this parameter, you need to consider the conditions in which you plan to use the projector. So, for office or school/university use, a brightness of at least 3000 lm is desirable — this allows you to get normal visibility without obscuring the room. In turn, among the top models a very low brightness can be found, because. such projectors are usually installed in rooms specially designed for them with good darkness level. And in ultra-compact devices it is impossible to achieve high brightness for technical reasons.
Detailed recommendations on the optimal brightness for certain conditions can be found in special sources. Here we note that anyway, it is worth choosing according to this indicator with some margin. As mentioned above, as brightness increases, contrast and colour quality decrease, and you may need to use the projector at a reduced brightness to achieve the desired picture quality.
Static contrast
The static contrast of the image provided by the projector.
Static contrast refers to the maximum difference between the brightest white light and the darkest black that a projector can provide within a single frame. Unlike dynamic contrast (see below), this parameter describes not conditional, but quite real capabilities of the device, achievable without the use of any additional tricks like auto-brightness. And since the quality of colour reproduction and detailing depend on contrast, the higher this indicator, the lower the likelihood that details will be indistinguishable in bright or dark areas.
Colour rendering
The number of individual colour shades that the projector is capable of displaying.
The minimum indicator for modern projection technology is actually 16 million colours (more precisely, 16.7 million is a standard number associated with the features of digital image processing). In the most advanced models, this value can exceed 1 billion. However, two nuances should be taken into account here: firstly, the human eye is able to recognize only about 10 million colour shades, and secondly, not a single modern image output device (projectors, monitors, etc.) cannot cover the entire spectrum of colours visible to the human eye. Therefore, impressive colour performance is more of a marketing ploy than a real indicator of image quality, and in fact it makes sense to pay attention to other characteristics — primarily brightness and contrast (see above), as well as specific data like a colour gamut chart.
Horizontal frequency
Horizontal frequency supported by the projector.
This parameter is relevant when working with analogue video signal. In such a video, the image is formed line by line: each pixel in the line is highlighted in turn, then the next line is highlighted, and so on. The horizontal frequency describes how many times per second the backlight beam runs from edge to edge of the screen. For normal playback, the projector must support the same refresh rate as the input signal was recorded. However, most models support a fairly wide range of frequencies, and there are no problems with support. Also note that if you are not a professional, then when choosing a projector, it is quite possible to focus on the frame rate (see below) — this parameter is simpler and more intuitive, and support for a certain frame rate automatically means support for the corresponding line rate.
Frame rate
Frame rate, simply put, is the frame rate supported by the projector.
For normal playback, it is highly desirable that the frame rate of the projector match the original frame rate of the video signal. However, most modern models do not support a specific frame rate, but a whole range of frequencies, and quite an extensive one at that.
Note that for viewing most video materials, the range from 24 to 60 fps is quite enough. The exception is 3D content, which may require double the frame rate, up to 120Hz (see "
3D Support " for details).
Size
The size of the panel/chip affects the depth and final quality of the image. The larger the panel/chip, the more light it is able to process, which means the picture will be clearer and more structured. The average projector has a sensor of 0.5-0.7″, advanced projectors use sensors of 1.2-1.5″ and more.
Image format support
Image formats supported by the projector.
In this case, format means the aspect ratio of the image. The general rule in this case is that the projector must support the same format in which the original content is recorded. Otherwise, the image will either be stretched in height or width, or with black stripes on the sides or top-bottom. Specifically, the formats can be divided into three main categories:
— Traditional, or
rectangular. Classic formats in which the height of the picture is not much less than the width. The most popular options are 4:3, widely used in analogue TV, and 5:4, common in computer technology. Traditional formats are well suited for presentations, working with documents and graphics, and other similar tasks.
—
Widescreen — formats in which the frame width is significantly (more than 1.5 times) greater than the height. The most popular of these standards are 16:9 and 16:10. These aspect ratios are well suited for games and movies; in particular, most high-definition content (HD 720p and above) is recorded in widescreen format.
—
Extra wide. The formats are even wider than the widescreen ones described above — for example, 21:9. Mainly used in cinematography.
It is worth noting that many modern projectors are able to work with several types of formats at once — for example, with classic 4:3 and
...wide-angle 16:9.Rear projection
The ability of the projector to operate in the
rear projection mode (“mirroring” the image).
There are two main types of rear projection. Most often, horizontal mirroring is found in projectors — it is used when installing the device behind a translucent screen. Vertical inversion, in turn, is used in projectors with fixed keystone correction — due to their design, when mounted under the ceiling, such devices must be turned upside down, which requires the corresponding correction of the displayed image.
Throw distance, max
The farthest distance from the screen that the projector can be used on. This is the maximum distance at which the image remains in focus and maintains acceptable brightness — at least enough for viewing in a darkened room on a high-quality screen.
It is necessary to choose according to this parameter taking into account the expected operating conditions and the distances to be dealt with. At the same time, it's ok to have a certain margin for the maximum distance — since, as already mentioned, it is usually indicated for an perfect screen and a darkened room, and such conditions are not always available. Also note that although the throw distances depend on the lens, not every projector with an interchangeable lens allows the installation of more "long-range" optics than the standard one — the device may simply not have enough brightness for an increased distance.
