Comparison LG HF80JS vs LG PF1000

— 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.

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 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.

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 optical zoom that the projector can provide.

Optical magnification of the image is carried out due to the operation of the lenses in the projector lens. With such an magnification, the size of the entire image changes; this can be useful both for adjusting the “picture” to the screen size, and for detailed viewing of individual details (the main thing is that these details do not crawl out of the screen when enlarged). In general, optical zoom is considered more advanced than digital one, because it allows user to adjust the diagonal without moving the projector, and maintains the original resolution of the "picture" regardless of the magnification. However lenses with such an possibility ("zoom lenses") are more complicated and more expensive than fixed optics, but the difference in price is almost imperceptible compared to the cost of the projectors themselves.

— 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.