Comparison Viewsonic PX725HD vs Viewsonic PX727-4K

The lamp model that the projector is designed for. Most projectors come with lamps included, so this information is not needed for normal use. But when looking for a spare lamp or replacement, information about model can be very useful: finding a spare part by the exact name is much easier than by general data like the brand of the projector.

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.

When working in economy mode, the brightness of the backlight is noticeably reduced, on average by 30-50%. With a decrease in brightness, heat dissipation also decreases, which saves the working life of the illuminator, thereby increasing the lamp life. Thus, the ECO mode allows you to extend the lamp life by an average of 30%. If the typical projector lamp life is 4000 hours, regular use of the ECO mode will extend the backlight life to approximately 5500 hours.

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 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”.