Projectors: Things to Consider When Buying

A projector is an electronic device that is used to display an image or video usually in an enlarged size by shining a high intensity beam of light on a flat surface like a wall or a sheet of cloth or canvas. White surfaces generally work best for projectors.

Nowadays, projectors have a wide range of applications. Within companies and organizations, they are used for presentation purposes for lectures, conferences or training courses. The projector has long been a standard in (universities) schools and other educational institutions.

Private users have long since discovered the advantages of the projector. With a projector you can bring the cinema experience into your living room at home. With large screen diagonals, watching films or playing games at home becomes a real pleasure. Constantly falling prices mean that the projector is affordable for everyone, and the projectors are also often used at events and public viewing. If you are looking for a new projector, the following aspects should be examined in more detail, in the truest sense of the word:

The premises

The rooms in which projectors are used can differ greatly from one another. The brightness value does not have to be too high in darkened rooms, but higher in brighter rooms or outdoors. In small rooms, the distance to the picture is often reduced too much, so the full surface of the canvas cannot be used at all. In larger rooms, the projector must be able to project the image sufficiently large so that all viewers can still see all of the content clearly. The interaction between the projector and the screen is very important. In some situations, noise from the projector can also have a disruptive effect.

The projector screen

In addition to the technical properties of the projector, the screen determines the image quality. The type of canvas surface is particularly important here. Their selection depends, among other things, on the brightness of the respective rooms and the luminosity of the projector. A distinction is made between daylight canvases and canvases for use in rooms whose lighting conditions can be regulated.

The gain factor

The so-called “gain factor” can be decisive here. The gain factor measures the reflection behavior of screens. The higher the luminance of a screen , the more the light is reflected from it. A high degree of reflection makes the picture brighter towards the center and therefore easier to read, but it also restricts the viewing angles. Among other things, it can then happen that the image can no longer be optimally read from an oblique viewing angle.

White “Type D” screens with a gain factor of 1 are often suitable for home cinema in the living room, whereas gray cloths with a higher gain factor are also used in light-flooded rooms. The gain factor should also be seen in relation to the light output of the projector. A projector with very high light output does not necessarily need a screen with a high gain factor. In contrast, the image of a low-light projector can be optimized by a screen with a higher gain factor.

Size of the Canvas

Of course, the size of the canvas also plays a decisive role, this is limited by the size of the room. You should always keep a certain distance to the screen to ensure a sharp view and not to overwhelm your eyes. This distance depends on the resolution:

Rule of thumb for Seat Spacing

4K resolution: seat spacing = screen width x 1
Full HD resolution: seat spacing = screen width x 1.5
HD Ready / WXGA resolution: seat spacing = screen width x 1.8
The lower the resolution, the greater the seat spacing.

Some canvases can be rolled out and in again at the push of a button with the help of an electric gear. In the case of the framed screen, however, the canvas remains permanently taut. There are also mobile screens on castors or tripod screens

Quality criteria of a projector

The technology: DLP or LCD?

The fundamental difference between LCD and DLP (“Digital Light Processing”) lies in the way images are generated. With DLP, the light is projected onto the screen via an integrated chip. There are around one to two million tiny mirrors on the surface of this chip. These reflect the light and thus create the individual pixels that make up the image.
LCD projectors, on the other hand, generate the image on LCD TVs or monitors. The light is passed through a prism and the basic colors are broken down and then directed through LCD chips. Another prism is then responsible for building up the final image.

Which is better DLP or LCD

This question is not easy to answer. In general, it can be said that both technologies are mature and high-quality projectors can achieve good results with both technologies. The so-called rainbow effect sometimes occurs with DLP projectors. In the case of very fast movements, a rainbow color spectrum can briefly flash. This is usually registered unconsciously. In addition to this rainbow effect, many people do not notice it at all, but sensitive people can get headaches from it.

This effect does not exist with the LCD projector. This, on the other hand, cannot display black tones as vividly and tends to have delays when moving quickly. In the worst case, this can result in a visible “dragging” of the image. In addition, the lamps from LCD projectors have a shorter lifespan. LCD projectors are well suited for presentations, as fonts are particularly easy to read here. DLP projectors are often better suited for fast motion sequences, for example when playing video games. LCD projectors are usually a little cheaper than DLP beams. Ultimately, the choice of technology depends primarily on individual preferences and the area of ​​application.

The larger the image to be projected, the darker it will appear on the screen. Because all the light that emerges must be able to cover a larger area here. So if you want to illuminate large screens with the projector, you have to take a closer look at the brightness value, which is measured in lumens (lm). As a rule of thumb, you should generally plan over 2000 lumens for a 2.5 meter screen. Especially outdoors and in bright rooms, the motto is: more is always better. Because in unfavorable lighting conditions you will otherwise very quickly have great difficulties reading the screen. However, if you only want to operate your projector in darker rooms, a value of around 1,000 lumens can be sufficient.


The resolution also depends on the intended use; with modern projectors it is often Full HD (1920 x 1080 pixels) as standard. This resolution is generally very common nowadays and is widely used.
Nowadays , one should no longer be satisfied with HD resolution, especially in the Heinkino area, as otherwise individual image pixels will become visible on closer inspection. For simple Power Point presentations, however, an HD resolution can still be sufficient. HD projection may be sufficient, especially in larger rooms in which the audience sits a little further away (e.g. lecture halls or conference rooms). High-end projectors project with a full resolution of 4,096 x 2,160 pixels (4K) and thus ensure cinema enjoyment from the Feisten, but they are also correspondingly more expensive.


The contrast value provides information about the maximum difference in brightness between the colors white and black. If the contrast ratio is high, the colors appear more vivid and brighter. If it is small, the colors are a little more matt and the blacks are more gray. This can affect the image quality, especially if you frequently look at pictures and videos. In order to achieve good results in the video sector, the contrast ratio should be at least 10,000: 1.
Screen size & projection distance

When buying a projector, always pay attention to the size of the visible image area. It indicates the size in which the image can be projected. Larger rooms with a large audience require a larger picture area than smaller ones. The projection distance determines how close or far the projector can be placed to the screen.

Aspect ratio

Depending on what use you are planning, the aspect ratio of the projected image also plays a decisive role. In general, the projection image can be adjusted to the respective ratio, but this means that black bars are displayed and the image area cannot be fully used as a result. A resolution of 16: 9 and sometimes 16:10 is particularly useful in the home cinema sector, since most films support this format. A 4: 3 aspect ratio would not be the optimal choice here. For business projectors, however, the 4: 3 format is quite common, since documents and Power Point presentations support this format.

power consumption

The energy consumption of a projector should not be underestimated with increased use and is significantly higher than with a television. The power guzzlers are the projector’s lamps, the light-emitting diodes of the LED projectors consume significantly less electricity. An energy-efficient projector should never exceed 350 watts.

Noise development

The waste heat that can arise when operating a projector is dissipated by its fan. This creates a noise that is sometimes audible, sometimes less audible. Particularly with projectors that are selected for playing films, one should pay attention to the respective noise development ( measured in sons or decibels). If the projector is used in small and bright offices, the operating noises can quickly disrupt the presentation. With screens in large rooms or outdoors, the volume of a projector plays a subordinate role.

The connections

A projector should have different connections in order to be able to connect game consoles, Blu-Ray players, PCs, laptops, smartphones or tablets; an HDMI interface is required for this. Cell phones and tablets are often connected via the MHL standard. An analog video input is sufficient for DVB-T and satellite tuners, as well as for some older game consoles.

> Other possible connections for the connection are S-Video, D-Sub or DVI. Before buying a projector, you should clarify which devices you want to connect and which connections are required for them. Integrated SD card slots and USB connections are particularly practical. If these storage media are connected to the projector, the projector can display their content without additional hardware. Here, however, you should make sure that the projector also supports all common formats. The content of the presentation can even be transmitted wirelessly to the projector via integrated or optionally available WLAN modules.

Projector Lamps

Choosing the right projector lamp can have a decisive impact on image quality and power consumption. Projector lamps are among those components that suffer from wear and tear relatively quickly and therefore have to be replaced regularly. An important purchase criterion is therefore the service life of the lamps. In addition, the luminosity is also decisive. The original projector lamps usually deliver good results here, but are usually a bit more expensive than compatible lamps from other manufacturers. LED lamps help save electricity and generally have a longer life expectancy.

The different areas of application

In order to be able to make the right choice, you should be aware in advance of how and where you want to use your future projector. If you only want to use the projector for short presentations, completely different criteria apply than for a home theater projector. Depending on the intended use, various factors and properties of the projector must be taken into account.

Lectures and presentations

Presentations – whether in the company, at the university or at conferences – are mainly given in large and brighter rooms. Therefore, the projector should be able to project the image as brightly as possible. Since mostly videos are not played back during presentations, the projector does not necessarily have to have a high 4K resolution, since the distance to the projection surface is usually larger here. Full HD resolution is usually completely sufficient here. Much more important here is the size of the projection surface.

Home cinema at its finest

With the right projector, you can bring the cinema experience straight to your home. When buying a projector for home cinema use, you should attach particular importance to an appropriately high resolution. Because in the living room you usually sit relatively close to the projection surface. With a low HD resolution, individual pixels become visible so quickly. Full HD should be mandatory here, better still 4K.

Gaming projector

Similar demands are made on the gaming projector as on the home theater projector:

High resolution and good picture
Medium brightness
Connection variety
Reaction speed

The speed of reaction is of particular importance here, as gaming fun is quickly spoiled by “dragging” the image. The faster a projector can process the incoming video signal, the smoother the motion sequences appear. Therefore, gamers should tend to use a DLP projector .

If you want to operate a projector outdoors, the brightness must be right – the brighter, the better. Such projectors are often used at major events as part of public viewing, where the requirements are particularly high. For professional use outdoors, the projector must have a very, very high brightness value. Sun protection is essential for outdoor projectors.

The sun must not shine directly on the canvas. Tent tarpaulins or large cloths can reduce solar radiation. Special screens that focus the light, as well as gray and dark gray screens improve the contrast and the brightness of the projection, ideally a pavilion or a beer tent is set up. HEREyou will find two projectors with very high luminosity, which are particularly suitable for outdoor projection. Make sure, however, to protect the technology from the weather.


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