Comparison Viewsonic PX700HDH vs Viewsonic PX701-4K

This parameter largely determines the ability of the projector to work in a well-lit room. For a dark room, 1000 lumens is enough to make the projection picture bright, rich, clear and understandable. But when working in a lit room, the projector will need at least 3500-4000 lumens. Do not confuse ANSI lumens with Peak lumens. These are two different brightness standards. To convert one type of brightness to another, you need to multiply Peak lumens by 10-12. The result will be an approximate value of ANSI Lumens.

However, experts do not recommend chasing high ANSI lumen brightness values. There are many professional projectors with brightness up to 3500 lm. The lower the brightness, the lower the power consumption, and at the same time, the life of the illuminator increases. Of course, if the projector will be installed in a work office or classroom where good lighting is required, it is recommended to purchase a model with ANSI Lumens brightness of 4000 lumens and more.

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 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 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.

The native resolution of the image produced by the projector matrix.

The minimum for modern projectors is actually the VGA standard, which assumes a resolution of 800x600 or close to it. The most limited of modern high-definition standards is HD (720); the classic size of such a frame is 1280x720, but projectors also have other options (up to 1920x720). A more advanced HD format is Full HD (1080), which also has several variations (the most popular is 1920x1080). And among high-end projectors there are models of Quad HD, Ultra HD (4K) and even Ultra HD (8K) standards.

In general, the higher the resolution, the clearer and more detailed image the projector can produce. On the other hand, this indicator directly affects the cost, and all the benefits of high resolution can only be appreciated if the reproduced content also corresponds to it. Note that modern projectors can work with higher resolutions than the “native” ones – for more details, see “Maximum video resolution”.

The actual maximum frame resolution that the projector is capable of processing and displaying.

Many models allow project images at a higher resolution than the actual resolution of the projector matrix (see above). For example, a 1920x1080 video can be displayed on a device with a frame size of 1024x768. However, the quality of such an image will be noticeably lower than on a projector, which initially has a resolution of 1920x1080.

The maximum resolution is closely related to both the overall picture quality and the size of the projection screen. The higher the resolution, the sharper the image details become. Of course, the screen size itself should be taken into account. The fact is that on a 40-50″ projection surface there will not be much difference between the Quad HD and 4K formats. A high-resolution picture will be able to show itself on a truly large screen.

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.