See Projectors under computing for general information.
There are several kinds of projectors. Some work better for specific purposes:
The hot new technologies in 2010 were.
SVGA (800x600) and WVGA (854x480) are still available and fine for powerpoint presentations or slide shows.
In May 2016 my computer club got a InFocus 2128HDa (1080P) $782 4.4 (21)
Projectors will give you a larger image and are more portable than a flat panel display, but they are not as bright (15-20 ftL (foot Lamberts) for a projector vs 37 ftL for a flat panel display) so require a darker room.
A sample of the 50 or more available.
Dec 2011 - High Def 720p or 1080p
If you want to want to watch videos in a bright room the Wolf Cinema DCX-1000i with a 1,000-watt xenon lamp for $85,000 puts out 5,500 lumens.
Lamp Life - Projector lamps usually don't burn out the way light bulbs do. They gradually get dimmer and dimmer until they go out. If you haven't replaced your lamp in awhile, you'll be surprised how much brighter your "old" projector can look with a new lamp!
Most have VGA and HDMI inputs
Type Pixels Aspect ratio (16:9 - High Definition Std) Computer Monitors SVGA 800x600 4:3 1.33:1 WVGA 854x480 16:9 1.78:1 XGA 1024x768 4:3 1.33:1 WXGA 1366x768 16:9 1.78 * WXGA 1280x768 5:3 1.66:1 * WXGA 1280x800 16:10 1.60:1 (WXGA 60-1) WXGA+ 1440x900 16:10 SXGA 1280x1024 5:4 1.25:1 SXGA+ 1400x1050 4:3 SXGA- 1280x960 4:3 * WXGA Wide Extended Graphics Array is a set of non standard resolutions 1280x800 16:10 was common for laptops but 1366x768 16:9, common on LCD TVs, is more common now; It works better for consumer entertainment with HD 720pVideo resolution standards
WSXGA 1600x1024 25:16 1.56:1 WSXGA+1680x1050 8:5 UXGA 1600x1200 4:3 WUXGA 1920x1200 8:5 WQXGA 2560x1600 8:5 QWXGA 2048x1152 16:9 WQHD 2560x1440 16:9 TV SD 720x480 4:3 (pixels are rectangular 10:11) HD 1280x720 720p 16:9 FHD 1920x1080 Full High Def 1080p 16:9 Cameras SLR 3:2 compact digital 4:3
DLP vs LCD vs LCoS:
LCD (Liquid Crystal Display) uses liquid crystals, one for each pixel, on glass panels. Light passes through these LCD (Liquid crystal Display) panels on the way to the lens and is modulated by the liquid crystals as it passes. Thus it is a "transmissive" technology.
LCoS (Liquid crystal on silicon) combines these two ideas. (Sony's SXRD and JVC's HD-ILA are LCOS variants) It is a reflective technology that uses liquid crystals instead of individual mirrors. In LCOS, liquid crystals are applied to a reflective mirror substrate. As the liquid crystals open and close, the light is either reflected from the mirror below, or blocked. This modulates the light and creates the image.
LCD and LCOS have 3 chips, red, green and blue.
Trueness of color is also one of the significant differences between two major types of projectors: LCD, for "Liquid Crystal Display", or DLP, for "Digital Light Processing". DLP projectors tend to be very bright with higher contrast ratios, and they have become popular for smaller, lighter, "ultra-portable" projectors. To produce a color image, DLP projectors reflect a light through a rapidly spinning color wheel, which can lead to a slight flickering of color and sometimes to an unnatural color appearance. LCD projectors often do slightly better with color, but they tend to shift the color a bit towards the blue range, and some significantly so. DLP projectors also run very hot, which can be a problem for a portable projector in particular.
Lumens and Contrast Ratio:
Higher lumens allow you to see a picture with more ambient light. i.e. you don't have to have a very dark viewing room.
A high contrast projector produces a picture with a rich, dynamic look, good shadow definition, and deep color saturation. Contrast gives "depth" to video images.
The contrast ratios noted on a projector's spec sheet can be reported in one of two ways. If it just says "Contrast," it usually indicates On/Off contrast, which is the ratio of the whitest white and the darkest black that the projector is capable of producing. If it says "ANSI contrast," the ratio has been determined by displaying a checkerboard pattern of white and black squares and measuring the relative brightness of each. On/Off contrast is always a larger number, and more typically listed on projector spec sheets, but ANSI contrast is a more accurate representation of what your projector is actually capable of during normal use.
ATSC - Advanced Television Standards Committee
Anamorphic lens - An add on ($3,000-$10,000) that allows super wide 2.3:1 displays.
Auto iris - Enhances contrast by closing down lens in dim scenes.
DLP - Digital Light Processing (see above)
E-TORL - Epson Twin Optimized Reflection Lamp. Minimizes both light defraction and light leakage, providing you with up to 50 percent more lamp life.
Fl or ftL- Foot Lamberts - See PFL below. Takes the screen into account and measures the total light that is being reflected back toward the audience.
Frame rate - frames/sec
Gamma - Relationship between input video voltage and output brightness. Determines how mid-tones appear as eye sensitivity is non-linear and display devices use different methods to account for this as well as their own display characteristics.
IRE brightness - Institute of Radio Engineers brightness measurement. Absolute black is 0 IRE, and peak white is 100 IRE.
LCD - Liquid Crystal Display - (see above)
LCoS - Liquid crystal on silicon (see above)
LHP - LED High Power lamp
Lumens - Light energy output by the projector.
PFL - Projector Screen Foot Lamberts (Fl). Convert the lumens produced by the projector to PFL using the following formula:
TEDR - Total Environmental Dynamic Range. Describes the actual contrast ratio achieved in a venue.
THX - THX is mainly a quality assurance system. THX is a trade name of a high-fidelity audio/visual reproduction standard for movie theaters, screening rooms, home theaters, computer speakers, gaming consoles, and car audio systems. They certify movie theaters, home theater components, video displays and other A/V systems for quality.
UHE - Ultra High Efficiency lamp uses a shorter arc length to achieve higher efficiency