Lamp power
The power consumption of the backlight lamp installed in the projector.
Theoretically, the more powerful the lamp, the brighter it is. However, this is only true when comparing lamps of the same type (see above); and even in this case, the brightness may also depend on the nuances of the design. Therefore, when evaluating the capabilities of a lamp, it is worth focus not so much on power, but on the directly claimed brightness in lumens (see below).
But what this parameter directly affects is the total power consumption of the projector: the lamp is the most “greedy” component of the device, compared to it, the power consumption of the rest of the electronics is very small. Also note that many powerful lamps have high heat dissipation and require cooling systems, which affects the size and weight of the projector.
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.
Dynamic contrast
The dynamic image contrast provided by the projector.
Dynamic contrast ratio is the ratio between the brightest white and darkest black colour that a projector can produce. Recall that 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. However, dynamic contrast is a rather specific parameter. The fact is that when it is calculated, the brightest white at the maximum brightness settings and the darkest black at the minimum are taken into account. As a result, the figures in this column can be very impressive, but it is impossible to achieve such a contrast within one frame.
By introducing this parameter, the manufacturers went to a certain trick. However, this is not to say that dynamic contrast has nothing to do with image quality at all. Projectors can use automatic brightness control, in which the overall brightness, depending on the "picture" on the screen, can increase or decrease. This format of work is based on the fact that the human eye does not need too bright areas on a general dark background and very dark areas on a bright one, the image is normally perceived even without it. The maximum brightness difference achievable in this mode of operation is exactly what described by dynamic contrast.
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).
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.
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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.
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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.Features
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Light sensor. A sensor that detects the level of ambient light. Most commonly used to automatically adjust the brightness of the projector to suit current conditions. So, in a darkened room, high brightness is not needed, but in daylight, on the contrary, you cannot do without it. You can also adjust the operating mode manually, but it is more convenient when the projector does it automatically.
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DLNA support. DLNA technology is designed to connect home electronics into a single network and exchange content in real time. One of its advantages is that DLNA devices are guaranteed to be compatible with each other regardless of model and manufacturer. In a projector, this feature can be used, for example, to view a movie on a large screen from a computer hard drive, or to display an Internet broadcast on this screen that was originally opened on a tablet. DLNA works on the basis of a standard local network, with a connection via LAN (see "Management ports") or Wi-Fi (see below).
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MHL support. The projector has
HDMI inputs that support the MHL standard. This standard is used to transfer video and audio from mobile gadgets (via microUSB) to external devices. Accordingly, this feature is useful for those who plan to connect smartphones and other portable equipment to the projector. At the same time, an MHL gadget connected t
...o a compatible HDMI port can also be charged in the process. Note that you can also output the MHL signal to a regular HDMI port, but this will require an adapter, and the charging function will not be available.
— Picture-in-picture. Ability to play two channels simultaneously on one screen: main and additional (in a separate small window). The sound is played only for the main channel. This mode allows, for example, to skip a break in a football match and not be late for the second half. Note that for this function to work, images must come from different sources — for example, from two different tuners, or from a tuner and an external device (DVD player, media centre, etc.).
— PJ-Link protocol. The projector supports the PJ-Link protocol. This is a service standard designed to control projectors over local networks (usually LAN or HDBaseT, see "Management port"). All PJ-Link-enabled equipment (projectors, controllers) is fully interoperable regardless of brand and manufacturer, making it much easier to build networks of multiple projectors and replace individual components in such networks.
— 3D support. Support for 3D implies the ability to reproduce three-dimensional stereoscopic images. A 3D image can be based on various technologies. Traditionally, active (see the relevant paragraph), passive (see the relevant paragraph) and hybrid 3D technologies are distinguished. Special glasses are required to view the three-dimensional image. In the case of active 3D, special shutters are built into the glasses, which operate from an independent power source. For passive and hybrid 3D, regular 3D glasses without battery power are sufficient.
— Active 3D. Active 3D technology is based on the principle of alternating flickering of the image. The flickering of the image on the screen is synchronized with the flickering of the lenses in the glasses, as a result, each eye receives a separate image, which makes the picture three-dimensional. The main advantage of active 3D is the ability to view images without reducing the original picture quality. You can look at the screen from any angle and from any position, while the image will still be three-dimensional. Among the shortcomings, there is the presence of some discomfort for the eyes, which occurs due to the regular flickering of lenses in glasses. Also, active 3D glasses may darken the original brightness of the image somewhat. Additionally, glasses of this type are very expensive.
— Passive 3D. Passive 3D provides the display of a double image. Passive 3D glasses use special lenses that cut off the duplicate image in such a way that each eye sees only the image intended for it, which creates the illusion of a three-dimensional image. The main advantage of passive 3D is that it does not tyre the eyes, which is typical for active flickering 3D. Passive 3D glasses are inexpensive.
— Interactive pen. The projector supports interactive pen technology. This technology allows you to actually turn the projected image into an interactive whiteboard: with a pen, you can draw, write and make notes directly on the projected image, which is especially useful during presentations and educational events. It is worth taking into account that the pens themselves and additional equipment for their work may not be included in the set.
— Multimedia (air mouse remote). Air mouse remote are devices that have a gyroscope, which allows you not only to switch menu items with the “↑”, “↓” buttons, but to use the remote control as a mouse. By directing it to the screen, a cursor will appear that moves in the direction of the remote control. This makes management easier and faster.
— Voice control. The projector's support for voice control allows you to dictate certain commands through the remote control. However, voice control does not cover all functions and recognition accuracy may require re-entering the command. If you need a more extensive range of functions, then pay attention to the voice assistant.
— Voice assistant. For a long time now, device control has been shifting to voice commands. For this, certain interfaces and systems are used. The most popular are Amazon Alexa and Google Assistant. For "apple" devices, this is Apple Siri, but this technique is not presented in projectors. At the same time, unlike the voice control function, the voice assistant does not just turn on this or that function, mode, makes it louder, quieter, but allows you to perform certain operations in applications, whether it is to launch the desired clip on Youtube or display the weather in the browser.Video connectors
Inputs for connecting external video sources provided in the projector.
— VGA. Analogue video interface, that considered obsolete, but still quite popular; VGA outputs are found in video technology, as well as in some computer graphics cards. It supports resolutions up to 1280x1024, which allows you to work with 720p video, but more advanced HD standards are out of the question. Audio signal transmission via VGA is not provided, the soundtrack for such a video will have to be connected separately.
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DVI. A video interface primarily used to connect projectors to computers. Initially, it did not provide sound transmission, but this possibility is gradually being introduced. Nowadays, several varieties of DVI are used. So, according to the signal format, purely digital DVI-D and combined DVI-I, which supports digital and analogue video, are distinguished. In both of these varieties, a two-channel digital data transmission format can be used, in which the maximum video resolution reaches 2560x1600 (in single-channel it is 1920x1200). Connectors and plugs DVI-D and DVI-I are compatible with each other if the number of channels matches, or if a single-channel video signal is connected to a two-channel input.
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DisplayPort. A digital interface originally designed for connecting LCD monitors. Modern versions are similar in capabilities to HDMI, they support HD resolutions of 1080p an
...d higher, as well as multi-channel audio transmission. However, such outputs are rare in video devices; the main area of application for DisplayPort has been and remains computer technology. In particular, it is this connector (as well as its reduced version miniDisplayPort) that Apple regularly uses in its computers.
- — DisplayPort v 1.2. DisplayPort v 1.2 has a bandwidth of 17.28 Gbps. This signal transmission standard has full support for FullHD video format. QuadHD and 4K formats are partially supported.
- Display Port v 1.3. The maximum bandwidth of DisplayPort v 1.3 is 25.92 Gbps. This version of DisplayPort provides full support for FullHD and QuadHD formats. 4K and 8K video modes are partially supported.
- Display Port v 1.4. The bandwidth limit of DisplayPort v 1.4 is 32.4 Gbps. This version of DisplayPort features enhanced support for 4K video, including 144Hz refresh rates, while DisplayPort 1.3 only limits 4K to 120Hz. Like the previous version, DisplayPort 1.4 partially supports 8K video modes.
— BNC. Bayonet type connector used to connect coaxial cable. Projectors use this connection to transmit analogue component video (see the relevant paragraph) or uncompressed SDI video. BNC refers to professional interfaces and is found in projectors of the corresponding class.
— S-Video. Analogue interface for video transmission (without work with audio). Provides two channels for transmitting image information, similar to the component input described below. However, on the one hand, S-Video uses only one connector instead of three, on the other hand, the bandwidth of this interface is noticeably lower, it is not suitable for HD resolutions, in light of which it is considered obsolete and is rare, mainly found in specialized video equipment.
— Composite. Initially, a composite interface is called an analogue interface for transmitting video and sound, using 3 separate channels (for the video signal and the left and right audio channels). However, in this case, most often only one connector is meant — for video; audio inputs on projectors are listed separately and are referred to as RCA (audio) (see "Audio connectors"). In general, the composite interface does not have a high picture quality, besides it is not suitable for transmitting an HD image and is considered obsolete. On the other hand, it is very common and is found not only in modern video equipment, but also in outdated ones; for example, you can connect a VHS-VCR to the projector through this interface.
— Component. An interface that is considered the most advanced among modern analogue video standards. The video signal with this connection is divided into three components transmitted over separate cables; this provides good interference resistance and sufficient bandwidth even for HD resolutions. But the sound in this interface is not supported.HDMI inputs
The number of HDMI inputs provided by the projector.
HDMI is a comprehensive digital interface originally designed for high-definition video and multi-channel audio. Today, it is actually a generally accepted standard, outputs of this type are available in the vast majority of HD-enabled video devices — media centers, Blu-ray players, computer graphics cards, etc. The presence of several HDMI inputs allows you to simultaneously connect several signal sources to the projector and switch between them in the projector settings without having to connect and disconnect cables.