- Projector buying guide!
- Classification of projectors
- Data sources
- Main characteristics
- Display technology
- Luminous flux (brightness)
- Contrast in a projector
- Image dimensions
- Light source. Lamps
- Noise level
- Types of input and output connectors
- How to choose a projector
Projector buying guide!
Many projector buyers do not understand the characteristics of such devices as well as the terminology used in them. For those who have not encountered this type of technology before it is difficult to navigate the huge assortment offered by the sellers and choose the optimal projector which will suit their purposes.
A multimedia projector is a stand-alone device that ensures the transfer (projection) of data coming from an external source (a computer or a laptop, a video recorder, a DVD player, a video camera, a television tuner, etc.) to a large screen.
Classification of projectors
According to their functionality projectors can be divided into three main groups:
- Projectors for business and educational purposes.
- Projectors for home theaters, gaming projectors.
It is also worth mentioning projectors which support 3D projection technology. In addition to the film industry they are becoming more common in business processes and in modeling.
Any projector can be used only when coupled with an external source of data.
Depending on the model and the cost, projectors can be equipped with various devices and interfaces ‒ a built-in TV tuner, a DVD player, Wi-Fi, Ethernet interface for immediate connection to the local network.
The PS/2 interface makes it possible to connect a mouse or a keyboard, and through the USB interface you can connect a USB flash drive or an external hard drive. Various connectors (HDMI input, DVI input, component video input, S-Video input, etc.) provide additional connectivity for projectors.
When choosing a projector, it is first of all necessary to decide what task the projector is to solve, to what sources of data it will be connected, and also in what conditions it will work.
The main characteristics of projectors are:
- The type of the matrix.
- Luminous flux (brightness).
Additional characteristics that influence the choice of a projector are:
- The characteristics of the lens.
- The number and types of input and output connectors.
- Functional features.
- Noise level.
This parameter is characterized by the number of pixels that make up the image.
The main resolution formats are:
- SVGA (800*600).
- XGA (1024*768).
- SXGA (1280*1024).
- HD (1280*720).
- Full HD (1920*1080).
The first number in each pair shows the number of pixels in the horizontal direction, and the second one ‒ in the vertical direction.
The higher the resolution, the smaller the size of the luminous elements is and the better the image on the screen is. However, as the resolution increases, the cost of projectors increases as well. Therefore, when choosing the resolution, it is recommended to take into account the nature of the data which is to be projected.
Use the following table
|The data to be projected||Recommended resolution|
|Computer presentations prepared with the help of power point, as well as simple graphics and large texts||800*600, 1024*768|
|Videos and movies of normal quality||800*600, 1024*768|
|Excel spreadsheets, small texts, architectural graphics||1024*768, 1280*1024|
|3D content, HD-DVD, BluRay, HDTV.
Drawings, geographical maps, etc.
The technical specifications of a projector indicate its nominal resolution corresponding to the actual number of pixels in the reproduced elements. As a rule, projectors are capable of receiving a signal with a smaller and higher resolution than the nominal one, due to the use of compression (data compression). In this case, the quality of the projected image becomes worse as the image parameters are distorted.
The best picture is obtained when the resolution of the data source and the matrix of the projector are the same.
In modern projectors various imaging technologies are used. Today the most common ones are liquid crystal technology (LCD, Liquid Crystal Display) and the technology of digital light processing (DLP, Digital Light Processing).
Each of these technologies has several advantages.
LCD projectors are characterized by high brightness
Their advantages are the following: a low cost, a low power consumption, a good colour saturation, realism and the stability of the image.
The disadvantages are a low contrast, in some models there is a “mosaic effect”, i.e. the picture may have a cellular structure.
DLP-projectors are characterized by high contrast of the image
The advantages are as follows: often more compact, high contrast images, a deeper detailing of shadows and black colors than in LCD models, reliable and durable.
The only disadvantage is that in low-cost models there can be a “rainbow effect” or “flicker effect”.
Luminous flux (brightness)
The luminous flux of projectors is measured in lumens. The choice of the required luminous flux should be made very carefully. It is necessary to take into account the size of the room, the size of the screen and the specific lighting conditions.
For home theaters, designed to watch movies in dark conditions, it is enough to use a projector with a flux of 1,000 lumens. If the video display takes place in a lighted room, you need to use a projector with a flux of 2,000 lumens and more.
Models with 3,000 lumens give you the opportunity to watch video without closing the curtains, even on a bright sunny day.
Contrast in a projector
Contrast is the difference in brightness of the darkest and brightest images. Its amount determines the depth of colour reproduction of the image, the discernibility of the details. If this characteristic is low, the black color will look like grey.
This feature is especially important if you choose a projector for home use. It is the high contrast that makes the image more realistic and three-dimensional.
In projectors with digital light processing technology (DLP) this characteristic is significantly higher than in models with LCD technology.
What concerns weight the following categories of projectors are distinguished:
- Stationary: more than 10kg. Such devices are characterized by high technical parameters, have a powerful luminous flux and a high resolution.
- Portable: 3-10 kg. Sufficiently compact, have a variety of interfaces, a high resolution and luminous flux. The functionality of such projectors is usually quite enough to watch films or conduct presentations in medium-sized rooms.
- Ultraportable: up to 3 kg. They have small dimensions, are compact, but their functionality is much lower in comparison with the above-mentioned models, which is worth paying attention to.
- Pocket: up to 500gr. Such devices are ideal for off-site presentations, since their dimensions are comparable to those of a mobile phone. Together with supercompactness, such projectors have limited functionality.
Most modern projectors are equipped with lenses with a variable focal length. In the most advanced models the lenses are equipped with electric drives which make it possible to zoom and adjust the focus not only manually but also with the remote control.
If the resolution is responsible for the image quality, good visibility depends on screen size.
A projector capable of enlarging a picture from 2 to 4 meters is suitable for a school, university or a large conference hall. That’s enough for an audience of 100 people to see everything.
For home viewing it is enough to have a screen with the length of its diagonal of up to 2 meters.
But in a small room it is not convenient to look at the screen with a diagonal of 2 meters, so there is a need for a projector capable of reproducing compact video from 0.5 to 1 meter.
Light source. Lamps
Each lamp has its own service life after which it will have to be changed. This period is usually indicated in the characteristics of the projector.
- UHP lamps ‒ are used in most modern projectors; they are compact, highly efficient, consume relatively little energy.
- LED lamps (LEDs) ‒ are used in ultraportable projectors; they are very compact, have low power consumption and long life time. The disadvantage is a low intensity of luminous flux.
- Laser lamps ‒ have a long service life, high brightness, but their cost is higher.
- Xenon lamps ‒ are used in the most expensive and powerful projectors.
In most projectors you can output not only video, but also sound. As a rule, in a small room the power of the projector’s built-in audio system is enough to provide a film or a presentation with a proper sound. In large halls you will need to connect external speakers.
Projectors of every model are characterized by their noisiness which depends on the design of the device and the power of the fans used in them. The noise level can be in the range from 20 to 45 dB. For comfortable work in small rooms this figure should not exceed 30 dB.
Types of input and output connectors
It is important to make sure that the projector can interact with the media that are to transmit the data for display. For this purpose the specifications are provided with a list of inputs located on the rear panel of the device.
If you want to play files from the USB flash drive, you need to search for the sign for USB on the list. To connect to a computer you need a connector for HDMI, which allows you to use it for a home theater or video games.
In large concert halls the quality of the transmitted signal is lost because of the long wires, so in such situations only the VGA connector and the appropriate cable are used. If you plan to connect additional sound amplification equipment, it is important to make sure that there is an RCA connector.
Modern projectors have a standard set of functionality, namely:
- The availability of the on-screen menu and the remote control.
- Vertical and horizontal image inversion.
- Brightness, contrast, and clearness settings.
- Colour range settings.
- Compatibility with 3D video content.
- Correction of geometric distortions in the image.
- The presence of the economy mode of operation (reducing the light flux by 15-20%, which increases the service life of the lamp by 1.5-2 times).
There are other parameters and characteristics of projectors, but in order to buy a high-quality device for non-professional purposes it will be enough to take into account those described above.
How to choose a projector
It should be remembered that there is no projector that would feature all functions. When choosing one, you need to decide on its purpose, analyse the main characteristics, and it is desirable to assess the quality of the image with your own eyes.
In some cases projectors are more in demand than television sets. They have a light weight and are easily transported. They allow you to create a large image and can be compactly placed on a table, fastened to the ceiling and do not take up much space.
Follow our recommendations and you will make the right choice when buying a projector. Then it will give you a lot of joy, good mood and unforgettable impressions while playing games, viewing a movie or showing a presentation to colleagues.