Tech Talk
explanation of digital jargon
Criteria for selecting a Digital Data & Video ProjectorBy Kenyon Wills
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The following will ask you questions, giving basic definitions that will allow you to efficiently trim down your list of possible projectors to manageable choices.
How portable must the projector be?
How will you use yours? Traveling room to room, building to building, or city to city, you’ll want to get one that creates a really super image above all else!
Projectors can be -
- Fixed Install models 10lbs and greate
- Portable models 5-10lbs
- Ultra-portable models 3-5lbs
Remember: The smaller the unit the smaller the audience which can be served well.
How big is the average space that you will project to (rear wall-to-screen distance)?
Divide distance in feet from screen to farthest audience member (or long axis of room) by 6.
The result will give you the appropriate acceptable screen height for the room.
This will ensure that image sizes arenot only visible but alsolegible by the average viewer. Bigger screens than provided by this formula are OK and usually better. Smaller are too small to be legible. Highly detailed texts, such as financial forms or spreadsheets will require larger screens. (Example: 30-foot room divided by 6 equals 5-foot high screen). -
Your screen should not go much below desktop level, so that people can see the entire image without heads in the way...
Under what lighting conditions does your projector have to operate?
Is the lighting at the screen (sunlight and incandescent) controlled? How much? If you have a consistent usage area, you will find that you can get away with a dimmer projector if you drop the lights a bit and draw some curtains. If you travel around, assume the worst: that your presentation room will face south without blinds, and have no dimmer switches. This type of environment is hostile to getting a good image. The light in the room will wash out the darkest parts. A brighter projector will look better than a dimmer one in lit circumstances because it has a greater degree of contrast between the lightest and darkest parts of the screen.
Why Brighter is better:
- Projection uses "shadows" or less light to produce gray and black. (What happens when an open door lets light into a movie theater? -the "shadows" are washed out)
- The shadow created by your hand in front of the projected beam is the darkest that "black" will ever appear under the conditions you try it in.
- Projection uses "light" or more light to make white and other colors.
- The eye relies on contrast (difference between "black" and "white") to "see" an image.
- Higher contrast makes images more vivid, real, & legible
- Ambient room light is necessary to keep your audience awake and in eye contact with you.
SMALLER, MORE PORTABLE PROJECTORS ARE RARELY AS BRIGHT AS LARGER ONES!!
To evaluate Brightness:
Projectors' brightness' are measured in "LUMENS". 2000 lumens is desirable and not too much to ask of a good machine. The optimal installation-oriented machines are currently pushing 4000-5000 lumens. This number continues to climb. Lamps are consumable, and cost $400-$600 each, with 1000-2000 hours being the average.
What is the highest resolution of signal/data that will ever be employed?
If you have a computer, it has a level of resolution. That level describes how detailed the image is (numbers are the actual number of dots in the picture).
Common computer resolutions and general descriptions:
- 640x480 - "VGA" antique and seldom seen in the business world anymore
- 800x600 - "SVGA" seen sometimes, but usually on very dated equipment and cheaper home theater models
- 1024x768 - "XGA" The common standard of many business machines and laptops in 1999-2000
- 1280x1024 - "SXGA" Less common in general business applications. Generally reserved for graphics intensive fields and science applications.
Laptop Note: It is possible to "switch" a computer's higher resolution level down to a lower level to meet a less expensive projector's lower capacity. This requires users to master a multiple step sequence of settings on their Windows Control Panel that can be frustrating and daunting the first time(s). -Getting comfortable with this action took me a week! Also - To turn down the resolution successfully, the computer's monitor must be turned off! You'll want that screen on and sitting on the conference table in front of you as you present. You will look at it for reference so that you don't have to turn your back on the audience to look at the information on the projection screen.
FURTHER INFORMATION about choosing or installing a projector, plasma screen, or complete system call: Kenyon Wills
S P I N I T A R
510-407-5299
