Main function
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 graphics 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-quality projectors with advanced parameters, an abundance of functions and, accordingly, a considerable price. They are characterized by high image contrast, support high-resolution video (including cinematic image formats), have optical zoom to scale the image without losing quality, provide the connection of multi-channel sound systems, and much more. The specific set of options in professional projectors may vary depending on the model, but in any case, these are the most charged devices with top-end characteristics.
— 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.
Lamp model
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.
Size
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.
Auto keystone correction
Automatic image alignment when the projector is moved away from the screen. If the central axis of the projection ray does not coincide with the central axis of the screen, then an effect in the form of a so-called keystone occurs. The projector uses a special software algorithm to emulate screen and projection ray alignment. This is not effect the quality of colour reproduction or the depth of textures, but the image can be aligned. The auto keystone correction feature works on the basis of a proximity sensor, which evaluates the difference between the sizes of the edges of the picture. If a keystone effect occurs, the projector straightens the picture without user participation.
Wi-Fi
Wi-Fi standard supported by the projector.
Wi-Fi is known mainly as a method of wirelessly connecting to the Internet and local networks. In addition, more recently, this technology has also been used for direct connections between wireless devices. Accordingly, the methods of using Wi-Fi in projectors may also be different. Thus, some models are capable of connecting to local networks to work with content via DLNA (see above); in others, such a connection is used for control from a computer or other network device; in others, a “remote control” like a smartphone or tablet can connect directly via Wi-Fi.
As for Wi-Fi versions, the most popular options in modern technology - Wi-Fi 4 (802.11n) and Wi-Fi 5 (802.11ac) - are quite compatible with each other, and the difference between them in this case is not critical. Therefore, you don’t need to pay much attention to these details when choosing.
There are also
Wi-Fi ready projectors, which do not have Wi-Fi out of the box, but when connecting the appropriate adapter (purchased separately) are capable of a wireless connection.
HDMI version
HDMI interface version supported by the projector.
About the interface itself, see above, and its different versions differ in maximum resolution and other features:
— v 1.4. The version released back in 2009. Despite this, it has quite decent specifications, due to which it continues to be used in modern video equipment. Specific features of HDMI v1.4 include 3D support, the ability to work with 4K video (4096x2160) at 24 fps and with Full HD at 120 fps. In addition to the original version, there are also improved modifications — v.1.4a and v.1.4b; they differ only in some 3D-related improvements.
– v 2.0. Standard introduced in 2014. Thanks to the increased bandwidth compared to v 1.4, it allows you to transfer 4K video at speeds up to 60 fps, as well as up to 32 channels and up to 4 audio streams simultaneously. In addition, this version was the first to introduce support for the 21:9 ultra-wide format, and the v2.0a update introduced HDR compatibility, with further enhancements to this feature in version 2.0b.
— v 2.1. A version released in 2017 also known as HDMI Ultra High Speed. The data transfer rate has indeed been significantly increased, allowing the support for video up to 10K at 120 frames per second. In addition, some improvements regarding HDR have been made. Note that connecting via HDMI v2.1 requires the use of special cables, although the basic features remain available when working with standard cables.