Choosing A Data Projector

Before making a purchasing decision, it is critical that you know just how the projector is to be used, and just importantly how it might be used in the next year or so. Sadly it seems that the over-riding consideration is price.While price must always be taken into account there are more important questions that need to be asked before the cost. Throughout this discussion I am primarily thinking of projectors used in the context of the church setting.

   1. What is the primary media to be projected?
   2. How large will the image need to be?
   3. What type of screen will be used?
   4. How much light will be in the room/on the screen?
   5. Can the room lighting be controlled?
   6. Where will the unit positioned?
   7. How will you control it?
   8. How many connection types do you need to allow for?
   9. What type of projector will work best?

Primary Media - What is going to be shown.

For most churches on of the driving reasons for using a data projector will be song lyrics. At the most basic this simply involves placing text on the screen in a similar manner to an OHP. While this is the starting point it is not long before someone is asking to spice things up a little with a picture behind the words, this progressing to having a moving background (e.g. water flowing over some rocks), and at the extreme a live video behind the words.

Determining not only what you want to do initially some thought needs to be given to how it may be used in the future.

The Venue

Now that you have determined what is being shown, the next area to work through is the where which is covered by points 2-5.

Look around the space and work out where the best location for the screen might be. Will everyone be able to see it? If not you may need to consider two smaller screens or perhaps some monitors to ensure that everyone can see.

The Screen

The location of the screen will also suggest a possible screen size. (I say possible because other features of the room and the final budget may alter this. Laughing )

It may be that you can utilise an existing wall space and if the wall is a light colour special screen might not be needed. Saving on purchasing a screen may allow purchasing a better projector as well. Some projectors have a wall colour setting that will compensate for beige, green, blue shaded walls, however the human eye is amazing, and after a very short time (seconds) it will reinterpret the colour it sees to be the colour that it knows that it should be. Ideally however a matte flat) white wall is the very best as it will provide better contrast between white and black.

Other screen choices include:-

    * Manual pull down
    * Motorised drop down
    * Custom built suspended screen - might be painted ply sheets, framed lycra or a specialised highly reflective material.
    * Rear projection screen - this is really a worthy of a whole independent topic, and is only really viable if you have a large space behind the screen location that can be completely blacked out.

Lighting

The amount of light both in the room (ambient) and shining directly on the screen is easily over looked. Often spaces have been designed to use as much natural light as possible so that they are "light and airy" or to minimise energy costs. It is vital that any data projection investigation should consider how much sunlight will enter the room at the normal times of usage. To maximise the on screen picture ideally all light can be controlled. (This includes removing reflections). It is common for many churches that have been built before 2000 to have banks of fluro tubes or sometimes a number of sodium vapour lights, both are great at filling a room with light however great image projection can only be achieved if it is possible to reduce the total room light levels particularly those around and on the projection screen area. To understand the significance of this imagine a piece of white paper in the location of the proposed screen, with standard lighting this now represents "black" on the projection screen and white is acheived simply by putting as much light as possible on that "black" surface. (This also has huge implications for contrast which will be dealt with later in this article.)

For daytime programs try to ensure that light levels are reduced with appropriate curtaining or blockout material. If possible turn off light that is shining directly on the screen. (NOTE Fluro lights are very diffuse and you may find that several rows need to be turned off to be effective.) If it is not possible to individually switch lights off it may be necessary to disable those closest to the screen, your local electrician can assist you with this.

For night time events another possibility is the use of "up" lighting, where the light is shone onto the ceiling. This can created a very soft atmosphere and usually helps to minimise light spilling onto the screen.

Projector Position

Actually before you can determine the exact location of the new projector you need to look at the specific measurements for your chosen projector, however more generally you need to decide whether the projector will be ceiling mounted or just sit on a stand on the floor. A couple of key advantages for mounting your projector from the ceiling are:- 1.) once setup it is always in position ready for use, 2.) the projection beam is over head allowing those on the platform to move around with little or no worry of blocking the beam, 3.) little fingers are less likely to tamper with it. There are some advantages to using a stand also:- 1.) Location can be altered to suit changing programs, 2.) Dust filter and Bulb can be easily changed, 3.) unit can be packed away securly. This leads us to the next point...

Control

In the excitement of purchasing a shiny new gadget it is easy to forget that for it to be easy to use the control interface must be easily accessable, this is especially true for ceiling mounted projectors as they are often many metres above the floor. There are several key options to consider here. All projectors that I have encountred (not including mega/stadium installations) come standard with a remote control, typically "infrared" although there are some wireless units.

It is at this point that some of the preceding questions begin to rise up. If the projector is ceiling mounted is there an infrared port on the rear (and/or sides) of the unit - most have at least one infrared port on the front face. Will the projector opperator be able to beam the remote to the port or will some other method need to be used (wired remote or infrared repeater unit). If the projector only has a front facing IR port the cost of adding a repeater or running control cabling may mean that it would be more cost effective to find a different projector which may included the necessary ports.

For some installations direct cabled PC control may be the preference. In this instance a small control program (supplied by the projector manufacturer) runs on the projection PC. This option while providing maximum control (it may even include bulb life and dust filter readings) may be overly complex for those that just want to be able to press a button and get things happening.

While an IR repeater unit will have a higher upfront cost it does offer the advantage that you should be able to reuse it if/when you upgrade projectors, you may even be able to set up a system for multiple identical projectors.

Connections

Given that most churches will be installing a data projector to display song lyrics it is likely that the most important connector will be the VGA (d-sub) connector. Fortunately this is a standard connector on virtually all current units. After this point however the options become less clear. Will you be using a VHS cassete player (yes I know there are still some out there!) or a live video camera or perhaps just a basic DVD player, if so then a composite video input will be needed (or perhaps an S-Video port for the purists). Some projectors also allow component RGB input although these are much less common. Later model units will begin to feature the new DVI and HDMI standards also however these are currently less suitable for use over distances greater than a few metres, and most installations will need a cable run of at least 20m. Recently there has been a increasing trend to include WiFi network ability, however this is typically not useful for anything other than static images, so while it my be very useful in a classroom or boardroom most church settings will get little value especially with video content. (Perhaps one day wireless data transfer will be sufficently fast for even the latest High Definition content to be streamed through the air).

Often a speaker/presenter will supply their own notebook based presentation. It is very handy to have a second VGA input on the projector so that an additional input is possible from the platform area.

NOTE while it certianly is possible use composite video only, provided the projection computer has a composite output, the resulting screen image will be degraded as the pixel based image is compressed into a picutre based format that is less than the original pixel count. This is especially evident in smaller texts. Usually I also find that the overall colour saturation and clarity take a hit also. SO even if the video team insist on a composite feed, PLEASE be sure to also include a VGA based input. It is much less expensive to install all these cables together than to have to run additional cables later.
Switching Inputs

One of the other features that that is much more difficult to pin down in projector promotional material is how input switching is handled. While the full AUTO mode sounds appealing it can have some unexpected consequences as a projector losses the main signal and begins to "hunt" for another. I have always found it best to be able to select the required input manually. This way you can switch from one input to another without the projector having to go through all the available options continually displaying "No Input" while you wait for it to find the right one. You may need to do a bit of research on this point.

Expensive connection & switching option :- At the big end of town you could always install a video switcher which allows you to move between a number of inputs, converting them as necessary to work on a single projection connection. Typically these switching units cost as much or more than the projector.
Going the Distance

Most PC/Laptop output should work fine upto 30m (I have managed 50m) without any signal boost to a VGA signal however it is wise to consider using a splitter booster as this allows additional cloned outputs while maintaining signal strength. Be sure that you get a powered unit as only these will actually boost the signal. Composite video will run quite a long way down a coax lead it is not uncommon to see 40 - 60 m runs. Obviously the shorter the better.

The Projector

Follow this link to the Data Projector discussion.