Comparison Optoma UHD40 vs Optoma UHD60

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 video 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-end projectors with numerous advanced features and, accordingly, high cost. Usually, they are equipped with interchangeable lenses, and some are supplied without a lens at all (see below). Also a characteristic feature of a professional projector is the BNC connector (see below), although there are models without it.

— 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.

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 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.

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.

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.

The projector supports HDR technology — high dynamic range.

This technology allows to expand the range of brightness displayed within a single frame — in other words, to display both very bright and very dark colours on the screen at the same time. Due to this, colour reproduction is noticeably improved; in addition, in very bright or very dark areas of the frame, small details remain visible that would not be visible in a normal image. At the same time, it is worth noting that all the benefits of HDR become noticeable only on a high-end screen with maximum dimming. In addition, this function significantly affects the cost of the projector, and the content must initially be recorded in HDR — and using exactly the technology that the projector supports (this point can be clarified in the instructions). Because of this HDR support is found predominantly among high-end home theater models (see "Main purpose").

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.

Diagonal size of the image projected by the projector. Usually, it is indicated as a range — from the smallest, at the minimum throw distance, to the largest, at the maximum. About throw distances, see above; here it is worth saying that the choice of diagonal size depends both on the distance between the screen and the audience, and on the format of the projector. For example, to watch a video, the best option is the situation when the distance from the viewer to the image corresponds to 3-4 diagonals, and a relatively large picture can be useful for working with presentations. More detailed recommendations for different situations can be found in special sources; here we only recall that the image must fit on the screen used with the projector.