Comparison AOpen QH10 vs Cheerlux C9

The main function of the projector.

This parameter is rather conditional, it largely depends on how the device is positioned by the manufacturer; however, for the most comfortable use, it is best to follow exactly the stated purpose. The options here can be: multipurpose, for presentations, for home theater, professional, portable, gaming. Here is a more detailed description of each option:

— Multipurpose. The simplest kind of projectors, roughly speaking – all models that do not belong to any of the specializations described below. Most of them have non-interchangeable optics, a throw distance of 1-12 m, an image diagonal of about 1-7 m (see below), and a relatively low cost.

— For presentations. Projectors designed primarily for business use, such as presentations. Usually they have a small throw distance with a rather large diagonal, which allows them to be used in small rooms; capable of working with both widescreen and conventional image formats (see below), and also support resolutions typical for computer graphics cards — for example, 1280x800. In this case, the actual resolution itself (see below) can be quite low. In addition, an almost mandatory feature of this type of projectors (with a few exceptions) is the presence of a D-Sub 15 pin input (see "Connectors").

— For home theater. Projectors designed primarily for film viewing. The main criterion for classifying a particular model in this category is how the projector is positioned by the manufacturer itself (in other words, whether this purpose is indicated in the official documentation). However, there are some common features: cinematographic models usually support widescreen image formats, have a high real resolution (see below) that allows you to work with HD video, and are also equipped with the appropriate interfaces (see "Connectors").

— Professional. High-quality projectors with advanced parameters, an abundance of functions and, accordingly, a considerable price. They are characterized by high image contrast, support high-resolution video (including cinematic image formats), have optical zoom to scale the image without losing quality, provide the connection of multi-channel sound systems, and much more. The specific set of options in professional projectors may vary depending on the model, but in any case, these are the most charged devices with top-end characteristics.

— Portable projector. An ultra-compact variety of projectors: most models are pocket-sized. Such devices are intended primarily for improvised presentations. The format of work and power supply may be different. So, some models are made as separate devices with their own built-in storages and batteries (and sometimes even with a full-fledged mobile OS like Android on board). Others are similar in design to external cases or consoles and are put directly on the mobile phone during operation, using it as a source of signal and power. However, anyway, portable projectors, due to their small size, have rather low technical specifications — they have neither brightness nor high image contrast.. Battery life (in models with their own batteries) usually ranges from 40 minutes to one and a half hours. Also, this variety is characterized by cost-effective LED lamps (see below).

— Gaming. Specialized projectors designed for use in video games. Outwardly, they are often distinguished by a characteristic “aggressive” design, while the design can be done in the style of a certain line of gaming PCs or laptops. As for the specifications, they, in accordance with the name, are aimed primarily at providing a high-quality game "picture". To do this, projectors for this purpose provide, in particular, high real resolution (not lower than 1920x720, and more often 1920x1080 or more), colour reproduction at the level of 1 billion colours, support for frame rate (see below) up to 120 Hz, and also at least one HDMI input for receiving a digital signal from a computer graphics card. In addition, such models often provide support for 3D. The maximum image diagonal can reach 7.5 m or more; at the same time, ultra-wide-angle devices are also found in this category, capable of providing an image diagonal of about 3 m from a distance of about half a metre.

Minimum projector lamp life as stated by the manufacturer. Specified by the total time of continuous operation. Note that if the projector was operated without violations, then upon reaching this time, the lamp will not necessarily fail — on the contrary, it can work for quite a long time. However, when evaluating durability, it is best to focus on the claimed service life.

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.

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.

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, 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).

The technology by which the projector sensor is built.

— DLP. This technology is based on a chip with thousands of rotary micromirrors. Each such mirror corresponds to one pixel and has two fixed positions — “lit” and “darkened”. In most DLP projectors, there is only one sensor, and the output of a colour image is provided by the colour wheel, thanks to which the projector alternately displays the red, green and blue image; they are replaced so quickly that the viewer perceives not individual frames, but a whole colour picture. Compared to LCD models (see related section), these single-sensor projectors are more compact and offer better image contrast with deep black levels (which improves black and white image quality). However, the brightness of the colour image in DLP devices is relatively low, in addition, they are subject to the "rainbow effect": in dynamic scenes, colour artifacts may be noticeable due to the mismatch of red, green and blue image components. Three-sensor DLP projectors don`t have these shortcomings; however, such a design is very expensive, so it is found rarely, mainly among premium devices.

— 3LCD. Technology based on the use of translucent LCD sensors. There are three such sensors, each of them is translucent with its base colour (red, green or blue), and the final colour “picture” is formed from three images simultaneously superimposed on each other. Thanks to...this format of operation, you can achieve brighter, more saturated colours than in single-sensor DLP projectors (see the relevant paragraph); in addition, this technology is completely devoid of the "rainbow effect". Among its shortcomings are the relatively low contrast ratio (in particular, due to the low black depth) and the larger size of the projectors.

— LCD(Liquid Crystal Display) — a colour rendering technology based on the modulation of light by liquid crystals. Do not confuse LCD and 3LCD sensors. 3LCD technology forms an image from three separate light streams, and in an LCD sensor, the image follows immediately from a single light beam. Sensors of this type provide a stable, contrasting and colour-rich image. Among the shortcomings of the technology, one can note the glimpse of the light grating, if you look at the picture from a close distance. Additionally, the substrate of LCD sensors is prone to fading, due to which the blue colour may begin to turn yellow over time (note that this can happen after a long time of active operation). LCD sensors require periodic maintenance, the service comes down to cleaning the air filter. LCD-sensor projectors are usually compact in size and light in weight, such models are prone to heat, and the noise threshold is above average.

— LCoS. A technology that combines the properties of DLP and LCD. Like LCD, it provides three separate sensors for the three primary colours (red, green, blue), and the final colour image is formed by the simultaneous superposition of these three components. The difference lies in the fact that in LCoS projectors the sensors are not translucent, but reflective. Thanks to this, you can achieve excellent contrast (as in DLP) combined with bright, high-quality colours without the "rainbow effect" (as in LCD). The main drawback of this technology is the impressive cost, which is why it is used mainly in premium projectors.

The closest distance to the screen that the projector can be used on. Typically, this is the minimum distance at which the image from the projector remains in focus.

This parameter is especially important if the device is to be placed at a small distance from the screen (for example, in a cramped room). Some modern projectors are able to work normally at a distance of 10 – 20 cm. Also note that the throw distances are determined primarily by the lens, and if the initial range of these distances does not suit you, perhaps the situation can be solved by replacing the optics.

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.