Comparison Optoma UHD60 vs Acer H7850

— HD (High-intensity discharge). General name for gas discharge lamps, i.e. lamps in which the light flow is created by an electrical discharge between the electrodes inside the bulb. In the case of projectors, such lamps can be mercury, metal-halide, and xenon (see above for more details).

— LED. LEDs are used as a light source. They provide high brightness with low power consumption.

— Laser-LED. Light source based on laser LEDs. It has even greater brightness than classic LED, with relatively low power consumption.

— UHP (Ultra-high performance) — a high-pressure mercury lamp, developed by Philips. Compared to other lamps, it consumes less power, while not inferior in brightness. Projectors on such lamps are smaller and lighter than conventional ones due to a smaller power supply, the cooler operates with a lower noise level. The creators claimed a service life of up to 10,000 hours. One of the most popular types of lamps for projectors today

– UHE (Ultra-High Energy). Variety of UHP lamps (see above).

— UHB (Ultra-high brightness). Another kind of UHP lamps (see above).

— NSH (New Super High Pressure). Also applies to high pressure mercury lamps manufactured by Ushio. Somewhat less popular than UHP and its peers, but also widespread. Estimated operating time is about...2000 hours.

— SHP. High pressure mercury lamps manufactured by Phoenix.

— P-VIP (Video Projector) — a high-pressure mercury lamp from OSRAM. High brightness lamps, service life — 4000 — 6000 hours.

—UHM (Ultra High Performance Lamp of Matsushita) is a high pressure mercury lamp manufactured by Panasonic. Сan be easily changed, operating time, depending on type — 2000 — 5000 hours.

— Xenon. The design and principle of operation of such lamps are similar to high-pressure mercury lamps — light is created due to a discharge in a gaseous medium. However, instead of mercury vapor, in this case, an inert xenon gas under high pressure is used. This allows to create high power lamps (from 2 kW) with the appropriate light flow. Xenon lamps are used primarily in professional models.

— HPM. High-pressure mercury lamp technology developed by Sony and used primarily in its projectors (although other brands are also available). Combines compact size and relatively low cost with high brightness.

— DC. Abbreviation for "direct current". In the case of projector lamps, this designation usually refers to mercury lamps powered by direct current. The operating voltage of such lamps in different models of projectors may be different. Their design usually uses various tricks to improve performance compared to conventional lamps of this type — in particular, increase service life and reduce power consumption without sacrificing brightness.

— AC. This abbreviation stands for "alternating current". Such lamps are similar in almost everything to the DC ones described above, differing from them only in the type of power supply.

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.

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.

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.

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.

The projector's throw distance is vital in determining what size projection screen to use and how far away it should be from the projector. Most projectors have a variable throw ratio. In the extreme positions, these are wide-angle mode (smallest value) and telephoto lens mode (largest value). Knowing these values, you will be able to determine the range of throw distances within which the projector must be placed in order for the projected image to match the specified dimensions of the projection screen.

According to these values, you need to check or set the optical zoom. We divide the larger value by the smaller value, and we get a figure, for example 1.33-2.16: 1.

If we want to calculate whether this projector is suitable for a certain image size, we do this: 1.33*3 (image width)=the distance at which the projector should hang.

The magnification range of digital zoom provided by the projector.

It is impossible to increase the diagonal digitally, so in this case we are usually talking about enlarging the image within the existing diagonal. Thus, for example, you can “stretch” a photo or diagram to fill the screen, removing the frames around the edges, enlarge a separate fragment of the image for a more detailed examination, etc. And in some models, digital zoom means, in fact, a reduction, when instead of the entire sensor only part of it is used. This can be useful if the original size of the image does not fit the screen.

It is worth noting that in both cases, the operation of the “zoom” is associated with a decrease in resolution and some deterioration in the overall quality of the picture.

The projector has a movable lens that can move at least vertically, and in the most advanced models — also horizontally. This feature allows you to adjust the location of the "picture" relative to the screen — most often it is about setting the image exactly in the centre. Using a moving lens for this is much easier than moving the projector or screen itself. Therefore, such models with lens shift can be very useful for those who are not sure that the installation location will optimally match the screen location.

— 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.

— 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).

— 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.