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Active Matrix

Term used to describe LCD Displays which have micro-transistors that "open" and "close" each pixel.

Active Matrix TFT The most common type of LCD used in most laptops, and projectors. A typical active matrix TFT display is a single panel of LCD glass that controls all three primary colors. TFT displays are noted for their quick response time and ability to display full motion video and animations without image ghosting.
Additive Color Mixture An ordinary color mixture process in  tube monitors and data/video projectors. When mixing red, green and blue light components with the same saturation, white will appear. The signal transmission usually happens split into an RGB signal via shielded cable
AFS (slide) Selective Auto focus. Corrects blurring fast and automatically. (Disengageable in a number of devices).
AGP-bus Acronym for "Accelerated Graphics Port". Along with ISA, EISA,  Microchannel, Local Bus and PCI another port/Bus in the PC area. It makes graphics faster and more realistic. The AGP-bus is only suitable for Graphic cards.
ALIS Alternate Lighting of Surfaces". A technology for Plasma Displays to improve the image quality by doubling the lines
ANSI Lumens A standard for measuring light output (brightness), that is used to compare  digital projectors based on ANSI (American National Standards Institute). An area of 1m2 on a screen is divided into 9 equally sized rectangles. The mathematical average of the light intensity in the centre of each area equals the ANSI lumens value. Unfortunately, there are enough variables, that the eye will often disagree radically with the ANSI rating. At best, ANSI lumens do fairly well comparing "apples" to "apples". If however one projector uses Halogen lamps and another metal-halide, the halogen projector will seem noticeably dimmer even if the two units rate the same. Other variables, including type of LCD technology (active matrix TFT, Poly-Si, passive), type of overall technology (LCD vs.DLP vs. CRT), contrast ratios, etc. all effect the end result.
Anti Jam System Prevents jamming or damaging of slides in the slide duct. To avoid any damage the slide transport is disengaged and the cooling fan continues to run.
Aperture (slide) The aperture is a measurement for the size of the opening of the lens. This size is alterable in small steps. The higher the aperture value the less light gets into the camera.
Artifact Failure in a digital signal evolving from compression or digitalization. Visible as image errors, aliasing, color blocks or color flickering, or in sound signals ambient noise such as chirping and clicking.
Aspect Ratio The most popular aspect ratio is 4:3 (4 by 3). Early television and computer video formats are in a 4:3 aspect ratio, which means that the width of the image is 4/3 times the height.    Examples:   A 15 inch monitor is 12 inches wide by 9 inches high (9 x 4/3 = 12). A resolution of 640x480 is a 4:3 format (480 x 4/3 = 640). Other formats are 5:4 used by the 1280x1024 SXGA resolution, 16:9 is used by HDTV, and 3:2 for 35mm slides.
ATA Rated Case A case rated strong enough to be shipped by common carrier; freight lines, UPS, FedEx, etc. Most ATA rated cases are easily recognized by their metal reinforced corners and handles. These cases are often referred to as "Anvil cases" bearing the name of one of the manufacturers.
Auto Balance A system for detecting errors in color balance in white and black areas of the picture and automatically adjusting the white and black levels of both the red and blue signals as needed for correction.
Auto Setup/ Auto Synch The projector recognizes the input source and automatically adjusts itself.
Autotimer (slide) With this function presentations can automatically run by defining times for cross-fading, i.e., in steps of seconds  from 1 - 60 seconds.
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Back Room Projector A projector with a "long-throw" lens designed to be used from the far back of the room, often in a projection booth, balcony, or back of an auditorium. Many typical projectors have third party lenses available for "long-throw" applications.
Backlit Refers to a remote control, or on projector control panel, that has buttons and controls that are illuminated. This is a major asset when using the projector in a darkened or semi-darkened room. Many projectors have backlit remote controls, while the number of projectors with backlit control panels is much smaller. As projectors have gotten brighter, room lights tend to stay on. So while a nice added feature, having backlit controls is no longer important to many users.
Bandwidth The number of cycles per second (Hertz) expressing the difference between the lower and upper limiting frequencies of a frequency band; also, the width of a band of frequencies.
Barrel Distortion Aberration with projectors where the margin lines of the image are convex. This is caused by aberrations of the lens. Opposite cushion distortion.
Blanking Shading a chart during a projection
Bluetooth The new wireless data transmission technology. Different kind of components and of different manufacturers can be combined to wireless networks for the first time.
BNC (Bayonet Neill-Concelman) A popular connector with video professionals which features a high loading capacity. Workstations have BNC cables with 5 connectors: one each for the three basic colors red, green and blue and one each for  horizontal and vertical synch
Brightness The attribute of visual perception in accordance with which an area appears to emit more of less light. (Luminance is the recommended name for the photo-electric quantity which has also been called brightness.)
Burn in Means an effect where an image is still latent visible even when the plasma display is switched off. This effect occurs due to an uneven fading of the plasma cells, i.e., caused by the insertion of TV station logos
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Carry-on Case Refers to a projector with carrying case that fits into the overhead bin or under the passenger seat of an airline. A projector case that does not fit these conditions will need to be checked as luggage, and ride in the cargo area of the airline. Make sure you have a good hard case when checking a projector as luggage. A projector is a delicate device that can have its LCDs misaligned when not handled properly.
CCD (Charge Coupled Device) CCD sensors consist of a one- or two-dimensional array of memory elements. They are mainly useful as image sensor in video cameras, scanners and digital cameras.
CE  All electrical and electronic devices which have been available for sale in the EU as of  01.01.96 have to bear this official seal. It provides information on the electromagnetic compatibility of the device.
Chromatic Aberration An optical defect of a lens which causes different colors or wave lengths of light to be focused at different distances from the lens. It is seen as color fringes or halos along edges and around every point in the image.
Chromaticity The color quality of light that is defined by the wavelength (hue) and saturation. Chromaticity defines all the qualities of color except its brightness.
Chrominance A color term defining the hue and saturation of a color. Often confused with brightness, the two terms are not interchangeable.
Cinch A connector primarily used for the transmittance of video - and audio signals
Cinch Connector and Jack (also called RCA) are today mainly used in the consumer electronics. Usually audio adapters are marked red and white (for Audio right/left) and video adapters are marked yellow
Coated Optics A variety of materials are put on to high quality lenses for several reasons. One of the key reasons to coat optics is to minimize the amount of light reflected back to the lamp and the amount of ambient light that mingles with the focused light leaving the lens. Generally good coatings can add 15% or more to the lenses brightness. Other coatings are used for filtering colors
Color Dynamics "The whitest whites, reddest reds, etc." High color dynamics are a result of dynamic range/contrast ratios. When we describe a unit as having excellent color dynamics, the practical description might be "rich colors, excellent definition, high contrast"
Color Temperature A method of measuring the "whiteness" of a light source. Metal halide lamps have very high temperatures compared to halogen or incandescent lights
Compact  Flash Card mobile memory used for PC-free presentations
Component  Video Signal Also described as color difference or YUV signal. The video signal is split into one brightness and two color difference signals, which are transferred separately. The image quality of the component signal is better than S-Video and therefore is employed frequently e.g. for the connection to DVD-players.
Compressed Resolution Anytime a projector can accept a higher resolution signal and compress the data down to fit its native resolution. As this affects the picture quality, several manufacturers have developed special compression methods, which actually compress with only the slightest loss of information. Quality of compressed images varies tremendously. Most but not all projectors offer compressed resolution for handling higher  than their native resolution. Some use simple "line dropping" schemes while others achieve varying degrees of higher quality with different "intelligent" algorithms.
Compressed SVGA Unlike CRT based monitors, LCD and DLP projectors only have one "true" resolution. Most projectors out there are VGA (640x480) resolution. To project an 800x600 image to a VGA projector, the original 800x600 signal must be compressed down to VGA. This is done by interpolating the data, and trying to best display all the information with only two thirds of the pixels (307,000 vs 480,000). The resulting image gives you the SVGA page size, but some sacrifice of image quality. For the vast majority of people with SVGA laptops or desktops, they will have more satisfying results outputting VGA to a VGA projector.
Compressed SXGA Found on XGA projectors, compressed SXGA allows  projectors to handle up to 1280x1024 SXGA resolution. Most owners of XGA projectors that use the compressed SXGA are workstation users (SUN, SGI, IBM, HP) The typical uses for these workstations are medical, life sciences, engineering and so on
Compressed XGA Found on SVGA projectors, compressed XGA allows projectors to handle 1024x768 XGA resolution. How good the compressed XGA is on a given model is a key factor in the decision process for most people choosing an SVGA projector. This is true as the market shifts from SVGA laptops to those with XGA screens
Contrast Ratio The ratio between the whitest and blackest portions of an image. The larger the contrast ratio the greater the ability of a projector to show subtle color details and tolerate extraneous room light. There are two different measuring methods: 1) Full on/off: In a dark room the brightness of the projection screen is measured at full white and full black. This process does not consider the refraction of light within the lens and therefore produces a very high contrast ratio. 2) ANSI: A chess board pattern of 16 fields black and white is projected to the screen. The brightness in the fields is evaluated and the contrast ratio is calculated accordingly. This process is far more practical and the numerical value is always lower than with the full on/off process. 
Convergence The congruence of the three LCD panels (red, green, blue) in a projector. Convergence error: Chromatic aberration in data projectors with three modules. Lines and outlines have colored margins. The reason - three projected component images for red, green, blue do not exactly comply with each other. Convergence errors mainly appear in the corners
CRT projectors Three-tube projector for ceiling mounting. Unlike digital projectors, CRT projectors are considerably heavier, more expensive and the adjustment requires a great effort.
Cushion Distortion Geometry error of lenses during projection which leads to a pin-cushion distorted image. Horizontal and vertical margin lines of the image are distorted up to the image center. This is caused by reproduction errors of lenses. Opposite barrel distortion
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D-ILA (Direct-Drive Image Light Amplifier) Direct (driven) Image Light Amplifier: Projected trademark of JVC. A technology for image formation in projectors on the basis of reflective modules.
Daylight Natural sun light or the emission of light with a colour temperature of 5.400 K up to 6.000 K
dB dB or decibel, is a measure of the power ratio of two signals. In system use, a measure of the voltage ratio of two signals, provided they are measured across a common impedance
Diagonal Screen A method of measuring the size of a screen or a projected image. It measures from one corner to the opposite corner. A wide screen has a diagonal of 15ft. Throughout this document we assume that the diagonal dimensions are for the traditional 4:3 ratio of a computer image as per the example above. Some screens are square, others particularly wide for 35mm slides 3:2 ratio. As such even if the screen is 12x12, we would rate it 15ft diagonal since that would be the diagonal of the usable area. OK, how about this! Remember high school? Here's your old geometry lesson. X-squared times Y-squared equals Z-squared. 3ft by 4ft screen = 3 squared (9), + 4 squared (16), equals 25 (5 squared) a 5 ft diagonal image.
Dichroic A mirror or lens that reflects or refracts selective wavelengths of light spectrum (a certain color), however, which lets all other portions of light passing.. Typically used in projector light engines to separate the lamps "white" light into red, green and blue light.
Dichroic mirror technology (slide) The light source has a reflector, so that the beam hitting the slide in a right angle first hits the mirror then reflects the slide. The mirror has the feature to absorb a part of the heat radiation so that the slide is not affected by too much heat.
Diffuse (projection screen) A reflection characteristic of projection screens. Diffuse reflective projection screens evenly scatter the incident light in all directions. The viewing angle is approx. 45 up to 60 degrees. The luminance factor is approx. 1.2.
Digital Light Processing (DLP) The commercial name for this technology from Texas Instruments (TI). The technology inside is often referred to as either "micro-mirrors", or DMD. It works this way: build a few hundred thousand tiny mirrors, and line them up in 800 rows of 600 mirrors each. Now attach a hinge to each of those 480,000 mirrors. Attach each of those 480,000 hinges to its own very tiny motor! Power each motor with electrostatic energy! The motors tilt their mirrors up to 20 degrees at incredible speeds. This allows the mirrors to modulate light from a lamp, and send the "modulated signal" out through a lens on to a screen. The most amazing part of DLP micro mirrors, is the scale of size. The 480,000 mirrors (actually 580,000 are used), hinges and motors are packed onto a "wafer" a bit larger than your thumbnail.
Dissolve (slide) Gradual change of an image into another with changing the brightness of two overlaying images
Distortion Optical aberration particularly emerging with zoom lenses. Hence cushion or barrel distortions occur at maximum setting of the zoom lens. Due to the often built-in upwards projection this error is particularly eye-catching at the top side of the image. The better the lens the less the error.
Distribution Amplifier An amplifier used to maintain a clean noise free signal to the projector over significant distances. Even with good heavily shielded cables, range of video and computer signals is limited to a few dozen feet before noticeable degradation. In ceiling mount situations, where the wiring may pass along side or across electrical conduits, etc. a distribution amp may be needed with shorter distances. Many distribution amps can also split the signal into 2 or more amplified signals for driving multiple projectors, projectors and monitors.
DMD (TM)/DLP The DMD/DLP (Digital Light Processing) technology developed by Texas Instruments contains hundreds of thousands of microscopically thin mirrors (1/1.000 of a human hair) on a semiconductor chip that are controlled electronically. Due to the newly developed control electronics the reflective projection light for each pixel is focused either onto the optical system or to the "offside" which finally produces the image. The color is produced by a three color filter wheels rotating "in sync" with the image control. Three separate color images are produced, one after the other, which appear as one true color image due to the high velocity. With this technology the pixel structure can almost not be identified. Bright images and an even spread of light are other features of this new technology.
DRIT (Digital Realized Interpolation Technology) Digital compression - and expansion processing from SANYO for full format images
Dual Scan Passive Matrix Newer version of the original passive matrix technology, where the screen is controlled by two processing systems. A bit faster than "single scan," response is still horrendously slow, they cannot do multimedia or video either. Contrast remains terrible. Dual scan is used in the least expensive LCD panels.
DVD (Digital Versatile Disk) Digital Versatile Disk, a new standard to save data on a CD ROM similar structure. Due to its high memory capacity the DVD is also able to digitally store movies. The quality is considerably better than S-VHS.
DVI (Digital Video Interface )  Digital Visual Interface is the new transmission standard that enables the digital transfer of PC data to a monitor, plasma display, projector, etc. As there is no conversion to an analogue signal the image quality improves significantly. There are three different interfaces: DVI-D: Transmission of true digital information; DVI-A: Transmission of true analogue information; DVI-I: Transmission of digital and analogue information.
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ECO Mode (Whisper Mode) Reducing the light output when using a digital projector. It reduces the fan noise and increases the lamp life
Extra bright lamp module (slide) Enables a higher light-source efficiency due to the dichroic mirror technology. (Kodak)
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Fade (slide) (Fade in, fade out). The increasing and decreasing of the lamp's light intensity, to make an image brighter or darker or to dissolve images
Fader The control on a projector, that allows you to control the balance of sound between the projectors internal speakers and the external speakers (PA, powered speakers). Only a couple of projectors offer this convenient feature.
Fan Speed Controller A sensor constantly controls the outside temperature. If the temperature is falling, the speed of the fan is reduced, thus the fan noise  is reducing automatically
Field One of the two equal but vertically separated parts into which a television frame is divided in an interlaced system of scanning. A period of 1/60 second separates each field start time.
Firewire The IEEE 1394 - technology, initially called Firewire, characterizes a relatively new (from 1995) serial interface technology for PC - and video devices to transmit digital data of up to 400 Mbit/sec
Fixed Focus Lens  A lens where the focal width cannot be changed. The image size can only be varied through the projection distance.
FM Based Remote A remote control that broadcasts its instructions with an FM transmitter, normally required in large rooms, thanks to long range, and no line of site requirement.
Focal Length It is the distance between the central point of a lens and the point where the beams are bundled (focal point). The bigger the focal length the closer targeted objects appear to be on the image.
Form Factor A general description of a major feature or features that identify a type of projector or category of capabilities.
Format Conversion (16:9) Movies are recorded by means of special camera technology (anamorphic), which compresses the image width. To display the right format, the correction can either be made within the DVD player or within the projector. We recommend that the conversion is carried out via a 16:9 format conversion inside the projector
Frequency Range Indicates the frequency range (in Hz), which a signal needs for transmission
Front Room Projector or Position Projection process where the image is projected onto a reflective wall. Contrast - rear projection. Generally the unit might be as close as 3/4 the screen size or as far as 1.2 times image size.
FXL The most popular halogen lamp in use in lower cost projectors and overhead projectors. The lamps typically last about 40 hours, however for convenience, most projectors using halogen lamps carry a spare, and a quick method of going to the backup lamp. Metal halide lamps and UHP lamps are used in most of the medium and higher priced, more powerful portables.
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Gain (projection screen) Luminance factor according to American Standard
Gear rack rube (slide) Current feature of Kodak  Ektapro/Ektalite lenses. Gear rack lenses are pushed that way into the lens mount housing that the gear rack rests on the gear wheel. The sharpness is achieved by turning the sharpness button. Gear rack lenses are used in Ektalite as well as in Ektapro models. (Opposite: Spiral tube (only Ektapro).
Gender Changer Adapter to change i.e. a plug into a jack. Is often required if the existing connection cable is only available in the wrong version
Glare-free fresnel lens Avoids light scattering thus allowing fatigueless working for longer periods
GyroPoint Patented technology to convert movements into electronic signals. Is used in products such as GyroMouse, GyroRemote and Ultra Professional which do not require any pad to control the mouse pointer thanks to this technology.
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Halogen Lamps  Used in most low and medium priced projectors, these lamps last about 40 hours, with consistent output throughout their life. Although halogens look very white compared to a normal incandescent lamp, they are not as white as metal halide units. Cost of operation: Under $0.50 per hour. Most projectors using halogen lamps carry a spare lamp inside
Hard Wired Remote Generally a remote control is wireless, and uses infra-red transmitter. There are situations where this is not practical: including large rooms where the speaker is 35 ft or more from the projector; Rear projection, where the screen will pass some signal, but normally has the presenter pretty much tied down. Also, the presenter has to point the remote "at" the projector which often means turning away from the audience. Some  projectors  offer wireless remotes that will accept a cable (hard wiring) back to the projector, assuring range and signal getting though.
HDCP (High-bandwidth Digital Copy Protection) it is a specification developed by the Intel® corporation to protect digital entertainment content that uses a digital visual interface (DVI). HDCP encrypts the transmission of digital content (signal) between the video source and the digital display. HDCP works by adding circuitry within the DVI connection on both transmitter (DVD player, cable box, etc.) and the receiver (projector, LCD TV, etc.) that encrypts video content. Software such as DVDs will not be affected as was the case with tapes for your VCR. Instead, the source players and the display device will be responsible for the encryption. HDCP is not designed to prevent copying or recording of digital content, but solely to protect the integrity of content as transmitted. Video source / transmitter = a computer, DVD player, or set-top box. Digital display / receiver = devices such as a monitor, digital television (DTV), or projector.
HDMI (High Definition Multimedia Interface ) "High Definition Multimedia Interface". New standard for the digital transmittance of high resolution Audio - and Video signals. The HDMI standard supports the coding of data to be transmitted whereby the unauthorized copying shall be prevented. If the projector or plasma display has no electronic to decode the data, the image either remains black or is reproduced with reduced resolution only.
HDTV (High Definition TV) Abbreviation for High Definition TV. This means the television transmittance with a significantly higher number of lines than present PAL- (625 lines, Interload) or NTSC-format (525 lines, Interload). There are modes  with 750 and 1.125 lines which have a progressive format without interlace. 
High Gain Screen A screen that uses one of many methods to collect light and reflect it back to the audience. This dramatically increase the brightness of the image over a white wall or semi-matte screen. Technologies used include curved screens, special metal foil screens (some polarized), and certain glass beaded screens. Prices and performance vary tremendously, but attention to the screen can make a big difference, particularly in "tough" environments such as trade shows.
High-light switch (slide) Increase of light output (therefore reduced lamp life ). Kodak.
Horizontal Frequency Indicates how many lines can be addressed per second (in kHz).
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IEEE 1394 See Firewire
Image Format Aspect ratio from image width to image height. All video formats have the conventional 4:3 format. Also for data formats VGA, SVGA and XGA  this ratio is maintained. The calculation of the image diagonal is very easy: Width to height to diagonal is 4:3:5. SXGA has a 5:4 image size while HDTV has the 16:9 standard size.
Image Size With an aspect ratio of 4:3 (VGA-, SVGA-,SXGA resolution) the image size values of a digital projector are determined as follows: Image diagonal = image width x 1,25; Image width = image diagonal : 1,25; image height = image diagonal x 0,6 or image width x 0,75
Infra-red Remote The traditional remote control, it transmits infra-red, just as a television remote. Typical range is limited to 30 - 35 feet. Infra-red requires line of site or a bounce off of a hard surface. The presenter must pay attention to where the remote is pointed. Some projectors have an IR sensor in both the front and rear of the projector, which can help. When working at or near the maximum distance, pointing right at the receiver is necessary. Remember "line of sight" - a person's head, directly between your remote and the projector may be enough to render it unusable. FM (radio frequency remote)  mouse systems, by comparison, have two distinct advantages, no line of sight requirement, and longer range.
Inline magazine projector (slide) Is equate by many with amateur projector as it is the most common projector type. The slide is tugged laterally by a slide feed in the optical path. Disadvantage for dissolve projections. Since the slide is pulled against a stop unit (for example a spring), a bounce effect will result. Hence, the collateral positioning varies even though it is only by a fraction of a millimeter. At the large projection, however, a fraction of an inch is visible on the screen. Inline magazine projectors operate with 150 W or 250 W lamps and are mostly small-picture projectors.
Interchangeable Lenses Thanks to interchangeable lenses with different focal width the projection image can easily be adjusted to the screen - or room size.
Interlaced This is an image formation where initially a half image (every second image line) is produced and thereafter the second half image is placed in the gap. Due to the double image frequency the flickering is reduced. All normal video norms work according to this principle while HDTV is working without line skip. Interlace is no longer common with data images
International Power Supply A unit that can operate under international selection of power requirements. The specs of units vary widely, but the minimum is 105-230 volts, and 50-60 cycles AC (alternating current). If you see a specification like 110v, 220v instead of a range, those ratings are usually +/- a given percent such as 10%. Some units are "self-switching" they will automatically switch to whatever power source you plug it into. Others will have to be switched (internally or externally)  to accommodate a different voltage or cycle range.
Interpolation Mathematical process to approximate out of known data the values of unknown data. The process plays a decisive roll in the magnified or decreased reproduction of images, particularly when adjusting the resolution to the module size of the data projectors. Magnified reproduction is called Resizing, decreased reproduction is called compression
Invert Image Invert image flips the image from top to bottom to compensate for ceiling mounting a projector upside down. Projectors typically ceiling-mount upside down, because most have "keystone" correction built in to compensate for the distortion created by "pointing up" from the table to the screen. Usual positioning has the projector about even with the bottom of the screen in a "table top position," or even with the top of the screen when ceiling mounted.
IR Infrared, invisible light with large wave length, used for the transmission of remote control signals.
IR Communication Standard Many new laptops have an Infra-Red transceiver that follow a recent standard for wireless communicating with peripherals (new laser printers complying with the standard) and networks or desktop systems. If you have a laptop like this, you know the pleasure of walking into a room with a configured laser printer, and printing out documents without having to "plug-in." Only a couple of projectors are  available that follow this standard. This allows their remote controls to talk directly to your laptop for remote mousing. A tremendous new capability, as you are normally much closer to your computer than the projector in medium or large rooms.
IR Mouse Remote Control The PC mouse can be controlled via the remote control of the projector
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Jack Connector primarily used for headphones and microphone connection, partly also as Audio - or Video connection
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Keystone Correction The innovation of using optics design or other methods to apply a "negative" keystone to the image, which will partially cancel the effects of keystoning. If you aim a projector with keystone correction at a screen with the lens level with the middle of the screen, you will note that the image at the bottom is wider than the top. When the projector is in normal position, pointing upward 10-25 degrees, the resulting image is fairly rectangular.
Keystone Correction Horizontal: If a projector cannot be placed in the right angle to the screen but due to space-saving reasons at a side, the distortions in an image are adjusted with an image processor
Keystone Correction Vertical Many digital projectors project as a presetting in a certain angle upwards to minimize the keystone effect. Some devices have an additional keystone correction, that means an image processor calculates the distortion-free image of the front - or downwards projection. Only a few devices resolve this optically (Lens Shift function).
Keystone effect Trapezoid image distortions with front or downwards projections. Can be corrected with tilted projection screen and/or with keystone correction. Keystoning is caused when the projected image is not perpendicular to the screen, making the top and bottom of the image different lengths for a trapezoid effect.
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Lamp economy switch (slide)  It reduces the light output of the lamp thus increasing the lamp life
Laser Pointer A small pen or cigar sized pointer, that contains a small battery powered laser. The laser pointer projects a small, red (typically), high intensity beam of light that is immediately  visible on the screen. Excellent for pointing to objects or textual projected display.
LCD  (Liquid Crystal Display) A system made of thin glass panels filled in between with a layer of liquid crystal. Thanks to electric mains all points of this layer can be activated individually. The precision of the activation is decisive for the quality of the projected image. LCD  panels come in many forms, sizes, and resolutions. Its primary purpose is to present a digital image for viewing. A common use of LCD panels  is as a display on a notebook computer.
LCoS (Liquid Crystal on Silicon) LCoS displays have the size of half of a thumb nail. Despite their small size LCoS displays have more than two million pixels and enable a resolution beyond UXGA (1600 x 1200 pixels). LCoS displays consist of three parts. A silicon film, on top comes a thin coating with liquid crystals and an extremely thin glass panel. By means of a special mirror the light of the lamp is reflected onto the LCoS display where again every single crystal is aligned per voltage in such way that the required image is projected
Lens Shift The lens can be moved mechanically from the principal axis of a projector. Due to the change of the projection angle the keystone effect is minimizing. The greater the angle, the higher the loss of light and the greater the image errors (cushion - or barrel distortions).
Line Doubler Electronic device or circuit turning video signals (half images) coded by the interlaced scanning into full images. The Line Doubler removes the annoying line structure. The simplest form doubles the provided lines. This results in homogeneous images
Long Throw Lens A lens designed for projection from the back of a room, or rather the back of a large room. Long throw lenses would be used in a projection booth in the back of a theater, etc. A typical long throw lens might have to be 50 to 100 ft from the screen to project a 10ft diagonal image.
Luminance Factor (projection screen) The measure for the efficiency factor of a projection screen according to DIN 19045 part 4: The luminance factor indicates the reflected part of the incident light. Measuring method: A light reading unit is arranged in the height of the light source and calibrated with a standard surface (standard-white) to 1. The measuring is made on the centre axis. Then the standard surface is exchanged with the projection screen pattern: The light reading unit now indicates the luminance factor for the relevant projection screen area. The measuring is based on different standards in various countries. In principle, only those projection screens can be compared with each other which have been measured according to the same standard Gain factor
Lux A standard for measuring light, numbers provided by manufacturers usually do not provide necessary additional information to compare one product to another.
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Manual Zoom The image size (the diagonal size of the image) is adjusted manually at the lens.
Maximum Distance Sometimes Maximum Distance refers to the distance from the screen that a projector can focus the image. Most of the time, however, it is the manufacturer's opinion of how far from a screen the projector can be to cast an image that is useable (bright enough) in a fully darkened room. Generally this is very subjective. One projector might quote a distance that allows them to produce a 25ft diagonal image, while a brighter projector might quote a distance that only equates to a 20ft image. Beware!
Maximum Image Size The largest image a projector can throw in a darkened room. This is usually limited by focal range of the optics.
Menu-Driven Refers to the type of controls on a projector. A typical menu-driven system, will first offer a menu of major categories such as Computer, Video, Audio, Display, Options. After selecting Computer, you will get another menu of choices with items like brightness, contrast, number of colors, color balance, sync. Select one of those and you can then adjust it. Many projectors which are menu driven, also offer the most widely used functions in a non-menu fashion, such as separate buttons on the remote for volume, brightness, and contrast, as well as switching between channels/sources.
Metal Halide Lamp The type of lamp used in many medium and all high-end portable projectors. These lamps typically have a "half-life" of 1000-2000 hours. That is they slowly lose intensity (brightness) as they are used, and at the "half-life" point, they are half as bright as when new. These lamps output a very "hot" temperature light, similar to mercury vapor lamps used in street lights. Their whites are "extremely" white (with slight bluish cast) and make Halogen lamp's whites look very yellowish by comparison.
Micro lens technology In front of the LCD panels of the projectors are micro lenses which have the task to bundle the light and guide it through the transistors so that the loss of light is as low as possible. Based on this technology a much higher ANSI-Lumen value can be achieved with the same lamp.
Microprocessor (slide) A small chip based central unit; the heart of the micro computer and memory coders. A micro processor control offers more ease-of-use and safety.
Minimum Distance The closest position that a projector can focus an image onto a screen.
Motorized Zoom The size of the image diagonal can be adjusted by electrically driven lens via infrared remote control independent of the location of the projection.
MPEG (Motion Pictures Experts Group) Compression standard for the data reduction of moving images. Unlike JPEG only the differences between two successive images are saved.
Multi norm Projection system with multi norm compatibility can project PAL, SECAM and NTSC video images.
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Network Projector A digital projector with the possibility to connect directly  to PC networks. The function provided by this network connection varies by vendor and reaches from a simple remote control up to transmitting complete presentations.
New progressive scan system A SANYO technology to enhance the image quality. Similar to a Line Doubler a special chip controls the reduplication of lines of moving image details at the projection of DVDs or other video images. The projections gain in image sharpness and color depth.
No slide - No light (slide) A shutter prevents the light spill in case no slide is in the slide gate. This is kind to the eyes and avoids the glare of the screen.
NTSC (National Television System Committee) A television standard for video and broadcasting with 525 lines and 60 half images per seconds interlaced popular in the USA, Canada and Japan. An older standard and lower resolution than systems used in most of the world.
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OEM (Original Equipment Manufacturer) A manufacturer of products being sold under a different company name.
OHP The common abbreviation for overhead projector – a device consisting of a light source, a transmissive or reflective platform, and a focusable lens assembly. An OHP is designed to project images from transparencies onto a screen. Before the launch of digital projectors on the market LCD projection panels were used with transmissive OHPs and worked enough  best with OHPs that produce at least 3,000 lumens. Since 5% to 10% of the light that shines through an LCD panel gets onto the screen, a 3000 lumen OHP will produce an image of 150 to 300 lumens. Transmissive OHPs are fairly bulky (bigger than many projectors). Reflective OHPs are fairly portable.
Optical Axis Responsible for the sharpness of  a projection image. Only if the projection head is positioned vertically above the lamp house and the concave mirror the user is able to get a sharp projection image. It is important that there is a stable connection between projection head and projection arm
OSD (On Screen Display) The menu  inserted into the projected image.
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P-bus interface (slide) The RS 232 standard interface (P-Bus) enables a communication exchange between projector and PC. Slide projectors can be programmed and controlled directly via PC. The command language is the KODAK EKTAPRO-P-COM protocol. The integrated micro processor in the Ektapro-projectors controls and coordinates all required functions.
PAL (Phase Alternation Line)  European and international broadcast standard for video and broadcasting principle developed by W. Bruch which is used in most parts of Europe with the exception of Czech Republic, Slovakia and France. The resolution is 625 lines, the frame rate 50 half images per second, the aspect ratio is 4:3. The enhancement is PAL Plus. Higher  resolution than NTSC.
PAL Plus Enhancement of PAL with an aspect ratio of 16:9 and improved signal processing
Panel Also known as a projection panel, LCD projection panel, or plate. The panel is the predecessor of today's projectors. It is slightly larger and heavier than a notebook computer and the LCD it uses to produce an image is very similar to that of the notebook computer. Because panels lack their own light source, they are designed to sit on top of a transmissive overhead projector (OHP). (See the definition of Overhead Projector for lumen performance.) Because of its small size, low cost, and versatility, panels had been a popular solution for education applications where an OHP is frequently available in the classroom for other instructional purposes. A few products had been built that integrated the panel and the OHP. These were some of the earliest projectors.
PanelLink An all digital interface used to transmit computer video from a PC/Notebook to a projector. Supports resolutions from 640x480(VGA) up to 1600x1200(UXGA). This digital interface might someday replace the analog VGA interface typically used to connect projectors to computers.
Parallel projection (slide) Several projectors are operated in parallel (simultaneously).
Passive Matrix LCD The original LCDs, these are controlled by a single processing system, for the whole screen, unlike active and poly-si, which have discrete circuits for each "pixel." This results in a panel with terrible color dynamics and contrast (typically 15:1). They are also incredibly slow: On passive laptop computers, the cursor (or anything else) moving on the screen, goes invisible until you stop moving it (submarining) Only one or two projectors use any type of passive matrix display.
PCI-bus Stands for" Peripheral Component Interconnect Bus". Along with ISA, EISA, Microchannel, LocalBus and AGP another slot/BUS in the PC area. Unlike AGP-Bus the PCI-Bus also accepts other add-on cards than graphic cards
PCMCIA (Personal Computer Memory Card International Association) International standard committee for credit card sized add-on cards for notebooks and digital cameras. Apart from memory cards there are also modem -, sound - and video cards in the PCMCIA format.
PiP (Picture-in-Picture) Several sources can be projected at the same time, i.e. simultaneous projection of a data - and a video source. 
Pixel (Picture Element) The smallest triggerable image part
Pixel Frequency Number of triggered pixels per second.
Pixel Shifter A screen saver function in plasma displays. It is used to reduce the burn-in risk respectively burn-in effect. The pixel-shifter moves the image content  in a pre-determined pattern over the display in certain intervals.
Plasma Display A new display technology. Each pixel consists of one tiny chamber which is filled with noble gas. This mixture of noble gas is lit by electronics. The emerging ultra-violet radiation stimulates the phosphor layer to illuminate.
Pointer Red dot or pointer which is inserted into the projection image via remote control thus attracting the attention of the audience
Polysilicon (PSI) technology  This technology is using polycrystal silicon which has much better electrical and optical features than TFT display. The lamp performance can be reduced but still a higher light output can be achieved. Today, lamp performances under 200 Watt up to 2.400 ANSI lumens are possible. The modules are significantly smaller than TFT modules. Currently, 0.7 inch up to 1.8 inch diagonal is dominating. Monochrome Poly-Si LCDs are typically placed in each of the three color light paths inside a projector, one each for Red, Green, and Blue. However, solely 3 chips are used because the color filters can not be integrated in the chip. The color separation is made via dichroic mirrors. Advantages: High brightness, strong colors, small light devices. Disadvantages: Gamma correction required, good convergence necessary. The modules are therefore often glued on the prism block. Poly-Si technology is also a bit faster than the Active Matrix TFT
Power Zoom A zoom lens with the zoom in and out controlled by a motor, usually adjusted from the projector's control panel and also the remote control
Progressive Scan Progressive scanning of the video signal consisting of two half images. Both half images are added to one full image. Thus subtle structures can dissolve
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QXGA QXGA is used to define a specific display resolution. Resolution is defined by the number of individual dots that a display uses to create an image. These dots are called pixels. A QXGA display has 2048 horizontal pixels and 1536 vertical pixels giving a total display resolution of 3,145,728 individual pixels that are used to compose the image delivered by a projector. A QXGA display has 4 times the resolution of an XGA display
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R&TTE New European regulation for devices which are communicating on radio basis
Random access (slide)  Direct slide access, i.e., from slide 10 to slide 20. There is no slide by slide selection but, for example, direct access to slide 20. Kodak.
Rear Screen Projection Using an opaque screen, the projector is placed behind the screen, invisible to the audience. The image projects onto the screen which the audience sees on the other side. Good rear projection screens actually produce brighter images than some standard screens. A projector with a short throw lens is typically used to accommodate the lack of space behind the screen. Since the projector can be placed at the ideal height, without blocking anyone's view, key stoning is not a problem. Since the image is projected through the screen, the image must be reversed.
Rear Projection For reverse projection in transmitted light mode. Requires special rear projection screens. Opposite front projection
Refresh Rate  Indicates how often an image can be displayed on the monitor per second (in Hz  -vertical frequency).
Resizing Mathematical process to fill up a signal of lower resolution to the format filling image of a projector with higher resolution. The dots not available in the signal are produced via interpolation. The result is a format filling bright image which appears somewhat fuzzy
Resolution The quantity  of  horizontal and vertical pixels. An optimal image quality is achieved when the resolution of the PC graphic card complies with the resolution of the projector. For laptops it is the resolution of the built-in monitor.
Reverse Image  Reverse image is a feature found on most projectors which flips the image horizontally. When used in a normal forward projection environment, text, graphics, etc, are backwards. Reverse image is used for rear projection
RGB (Red, Green, Blue) Color synthesis process. Additive color mixture. The standard type of monitor used with computers. Examples of usage: RGB input or output often referred to as computer input or output.
RJ-11  International standard connection type for analogue telephones - also called "Western Connector". This connector is used for the connection of  phone communication devices. This standard connector originates from the USA. Since the connector is quite reasonable, it is in the meantime also common for EU and other  telecommunications.
RJ-45 International standard connector for ISDN   and LAN cables
Round magazine projector (slide): The synonym for the professional slide projector. These slide projectors operate according to the slide gate principle: The slide to be projected is transported via a slot and falls down gravity-wise. Once it has arrived the slide stage it is pressed-on and is locked in its position. This enables a high accuracy of positioning and therefore it is suitable for continuous operation. Mostly these projectors operate with a 250 W or also a 400 W lamp.
RS-232 (Recommended Standard 232-C) Interface, which enables a control of the projector via PC or control unit such as AMX or Creston, also called V.24
RS-422 Transmittance standard for serial transmittance of PC data. Unlike RS 232 - standard up to 1.200 m can be bridged with RS 422. The trade offers complying modifiers which can transform a RS 232 signal into a RS 422 standard.
RS-485 Standard for serial transfer of PC data. Comparable with the RS 232 - standard. Here, also 1.200 m can be bridged. There are complying modifiers on the market which can transform a RS 232 signal into a RS 485 standard.
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S-Video A high quality video transmission standard, where the light signals are separated from the colour signals. Uses a 4 pin mini-DIN connector to send video information on two signal wires called luminance (brightness, Y) and chrominance (color, C). S-Video is also referred to as Y/C. A composite signal, typically found coming out of an RCA jack on the back of most VCRs has the Y and C information combined into one signal. The advantage of having luminance and chrominance separated is that a comb filter is not needed inside the video projector to separate the composite signal into the luminance and chrominance signals. A comb-filter can reduce the sharpness of your video image. Used with S-VHS recorders., etc.
SCART Also called EURO AV connector. The maximum 21 pin cable transmits all audio and video signals with only one connector. SCART is also suitable for S-Video
SD Memory Card Compact and solid memory medium in credit-card sized format Panasonic, at present with up to 512 Mb memory capacity. Currently the smallest design of electronic memory cards. Advantage: Large memory capacity, fast access time, erasure protection. The standard is supported by more than 230 suppliers. The cards are used among others in MP 3 players, digital projectors, digital cameras, PDA’s. Can be used via a PCMCIA adapter in any PC with PCMCIA slot.
SECAM (Sequentiel Couleur a Memoire) Sequential Couleur A Memoire (sequential memory recreation of colors)- television standard used among others in France, former USSR republics, Czech Republic, Slovakia and Japan. Like PAL, the number of lines is 625, the frame rate is 25 frames. Higher resolution than NTSC.
Selective Auto Focus (slide) With the focusing key the automatic focusing can be adjusted at any time. The Auto focus is then automatically switched off and after pressing the slide changer it is switched on again.
Short Throw Lens A lens designed to project the largest possible image from short distance. They are often required for rear projection, where the depth behind the screen is limited. A typical short throw lens might produce a diagonal image size of 10 ft, from a distance of 7 to 10 ft.
Single slide holder (slide) This enables the quick presentation of a slide without having to sort it into the magazine. Wrongly sorted images are grabbed instantly.
Slide AV Umbrella term for any imaginable connection of slide and audio, a modern term for an audio image show.
Slide control unit External control unit for the programming between a slide projector and a tape recorder.
Slide gate Dual-plane pressure system slide gate for optimal slide positioning. Horizontally : the slide is pushed to the slide gate for plane positioning. Vertically the slide is simultaneously adjusted at the sides so that the slide is exactly aligned at the dissolve. Projectors which are used for professional Multimedia shows (slide shows with dissolves etc) require this feature. For example, Kodak: all Ektrapro series models except E 320 have this feature
Slide light box For slide preview some projectors feature a slide light box at the top side which is visible when opening a sliding cap.
Smart Media Card Very small memory card, i.e., as used for digital cameras. They are even smaller and cheaper than PCMCIA memory cards.
Soft-slide-change (slide) Soft slide changer that prevents a hard light change during the slide transportation
Specular (projection screen) Reflection feature of projection screens. Specular projection screens reflect the incident light along the projection axis twice as much as diffuse reflective projection screens. The viewing angle is approx. 20 to 35 degree. The luminance factor is approx. 2.4.
Spiral tube (slide) Old Kodak S-AV lenses are based on a spiral tube. However, they are not used in the Ektalite models but only in the Ektapro series. The lenses are screwed clockwise from ahead into the lens holder. The focusing is adjusted by turning the lens.
Split Screen Some plasma displays have an in-built split screen function that allows the interconnection of several plasma displays to one large plasma screen. Each plasma display shows one part of the total image.
sRGB (Standard Red Green Blue) sRGB is a color standard developed by Microsoft for identical colors at PC peripherals. Is increasingly used with digital projectors. The aim is the exact display at any device (monitors, plasma displays, projectors) of colors of the original artwork.
Subtractive color mixture Complementary color mixture deposited on white surface turns out black. This method is used with the four color printing. The basic colors are yellow, cyan and magenta. Black is used for saturation. Opposite additive color mixture.
SVGA (Super Video Graphics Array) Graphic standard for PC’s with a maximum resolution of 800 x 600 pixels. SVGA is used to define a specific display resolution. Resolution is defined by the number of individual dots that a display uses to create an image. These dots are called pixels. An SVGA display has 800 horizontal pixels and 600 vertical pixels giving a total display resolution of 480,000 individual pixels that are used to compose the image delivered by a projector.
SXGA (Super Extended Graphics Array) Graphic standard for PC’s with a resolution of 1,280 x 1,024 pixels .SXGA is used to define a specific display resolution. Resolution is defined by the number of individual dots that a display uses to create an image. These dots are called pixels. An SXGA display has 1,280 horizontal pixels and 1,024 vertical pixels giving a total display resolution of 1,310,720 individual pixels that are used to compose the image delivered by a projector.
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TCP/IP Abbreviation for "Transmission Control Protocol over Internet Protocol". The Internet Protocol (IP) is used for the fragmentation and addressing of data and conveys these from the transmitter to the receiver - however does not protect the transmission. The Transmission Control Protocol (TCP) ensures that the sorting of packages reaches the receiver in the right sequence and provides the securing of the communication by confirming the receipt of the package. It corrects transmission errors automatically.
TFT Thin Film Transistor
TFT technology The basis of this technology - like the Psi technology - is LCDs. However, only one display is being used. The surface of the display consists of pixels which again consist of three transistors (one for every primary color). Therefore the name Thin-Film-Transistor- Active-Matrix. The TFT technology has stood the test on the market and is particularly suitable for projections without any moving images. It offers pin-sharp images and clear color contrasts. One considerable disadvantage is the high loss of light with identical light source, in comparison to other technologies.
Throw Ratio The ratio between the projection distance and image width in m. A throw ratio of 1,3 - 1,8:1 means, i.e., the lens of the projector achieves an image width of 1 m at a projection distance of 1,3 and 1,8 m..
Tint Tint, tinge; In the video area in particular for the correction of phase errors at NTSC-signals
Triac (slide) Electrical control element in slide projectors to infinitely vary the brightness of the projection lamp via impulses while dissolving slides.
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UHP Ultra high performance lamp developed by Philips. A modern lamp type which is particularly powerful but only requires little energy.
Uniformity Uniform illumination of an image area. Physically based brightness of a projected image reduces itself from the centre to the sides. Projectors tend to a brightness reduction of below 15 % to the sides which complies to a specification of 85% uniformity.
USB (Universal Serial Bus) Computer interface. Hardware components are automatically detected (except Win 98), configured and are instantly available when connected to the PC. With projectors currently only usable for the mouse interface
UXGA (Ultra Extended Graphics Array) Graphic standard for PCs with a maximum resolution of 1600 x 1.200 pixels. UXGA is used to define a specific display resolution. Resolution is defined by the number of individual dots that a display uses to create an image. These dots are called pixels. A UXGA display has 1,600 horizontal pixels and 1,200 vertical pixels giving a total display resolution of 1,920,000 individual pixels that are used to compose the image delivered by a projector.
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V24 See RS-232
Variable Focal Lens The projected image diagonal depends on the distance between the projector and screen. A lens with variable focal width (270 - 340 mm) prevents annoying blue or yellow frames.
Vertical frequency Indicates, how many frames per second can be displayed (refresh rate, in Hz).
VESA M1 A new standard connector at PCs, monitors, plasma displays and digital projectors. It was developed by the VESA "Video Electronics Standard Association" to enable the Plug&Play connection of different devices. The VESA M 1 connector not only allows the transmittance of digital and analogue image signals from the PC to the display gadget, it is also used for the connection of USB gadgets, i.e., a USB mouse or Firewire/IEEE 1394 signals. Additionally, there is also a supply voltage available where the devices connected at the VESA M 1 port can be supplied with voltage (low voltage devices with a small demand). There are three different VESA M 1 standards in total: - VESA M 1 - A to transfer pure analogue signals (30+4); - VESA M 1 - D to transfer pure digital signals (30); - VESA M 1 - A/D to transfer analogue and digital signals (30+4).
VGA VGA is used to define a specific display resolution. Resolution is defined by the number of individual dots that a display uses to create an image. These dots are called pixels. A VGA display has 640 horizontal pixels and 480 vertical pixels giving a total display resolution of 307,200 individual pixels that are used to compose the image delivered by a projector.
Viewing Angle The viewing angle is directly connected to the luminance factor. The higher the luminance factor the more limited is the viewing angle. The viewing angle is determined by where from the centerline (0 degree) the luminance factor has decreased by half.
Viewing Field Equals to twice the viewing angle.
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Whisper Mode See Eco Mode
Wireless LAN (WLAN) Recognized standard for wireless transfer of data between PCs or other electronic devices. According to the norm IEEE 802.11a up to 55 Mbit per seconds of data can be transmitted. Currently no adequate replacement for cable transfer since the transmittance is not made in real time.
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XGA (Extended Graphics Array) XGA is used to define a specific display resolution. Resolution is defined by the number of individual dots that a display uses to create an image. These dots are called pixels. An XGA display has 1,024 horizontal pixels and 768 vertical pixels giving a total display resolution of 783,360 individual pixels that are used to compose the image delivered by a projector.
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YUV Format, which is using one signal for the brightness (Y) and two for the color (U, V). Mostly the UV resolution is lower than the Y-resolution since the human eye is more sensitive to changes of brightness than to changes of colors.
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Zoom Lens A lens with a variable focal length. You can adjust the size of the image on a screen by adjusting the zoom lens, rather than making the projector closer to or further from the screen.
Zoom Lens Ratio The ratio between the smallest and largest image that a lens can project from a fixed distance. For example, a 1.4:1 zoom lens ratio means that a 10 foot image without zoom would become a 14 foot image with full zoom. Conversely, a 10 foot diagonal image at 15 feet with no zoom would still be a 10 foot image at 21 feet at maximum zoom (15 x 1.4 = 21 feet). A zoom lens is "not as bright" as a fixed lens, and the higher the ratio, the less light output.

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