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In this category it is especially important to ensure that you will be able easily to replace the essential parts to keep your equipment up and running, and this is especially so for projectors — and most especially for their lamps. Lamps are essentially just light bulbs, and they must periodically be replaced. Think of lamps, not as computer parts but  as computer supplies, because they certainly do get used up over time.

These are heavy duty industrial tools, and their price tags are accordingly steep. They are designed to replicate disks in huge quantities, and to keep on doing so over many years of reliable service. The primary difference between them concerns  the degree of process automation and intelligence built into each machine. If you want to produce mass quantities of disks without the need to attend to the process (and perhaps to pay an employee to do this work), you must expect to pay more upfront for the machinery.

How to buy a DVD drive.

The two new optical drive formats, Blu-ray and HD DVD, are being backed by Enterprise titans, Sony and Microsoft respectively. One may confidently expect that neither will wholly prevail, and that therefore one day soon drive makers will come up with drives that are compatible with both. There will always  be some people who want to be early adopters. They tend to be technologically savvy, and probably do not need to read our simple how-to buy tips. 

There are also two kinds of disks, single (SL) and dual layer (DL). Each single-layer disk can store up to 4.7GB, and each double-layer or dual-layer disk can store up to 8.5GB. These disks are inexpensive, though the latter costs more because they are more difficult to produce. Eight point five gigs is enough to store a two hour-long video. Think about just how much storage you really need.

While speed is an asset, remember this rule (a variant on the rule that you cannot eat your cake and have it too): the more slowly you burn your disks, the more perfect your recording is likely to be.

The compatibility factor.

Most DVD drives support reading from and writing to the major incompatible formats, DVD-RW and DVD+RW, and many also support DVD-RAM as well. These last may be called super multi drives. The drive you buy simply must support both of the first two formats for inter-machine compatible reasons. It probably should support DVD-RAM as well, because this format has the most robust error correction available, and it will give you random access to a rewritable disk, much like a hard drive does. While DVD-RAM is the least compatible with the drives that are out there in consumerland, it has yet another advantage. Using RW disks, it can rewrite up to 100,000 times, which in practice, and barring some accident, means that your disks will last for a lifetime or two or three. DVD-RW and DVD+RW formats can only rewrite up to about 1,000 times.

This technology is by  now quite venerable and familiar. However, there is one possibly important point that people often overlook. There is a tradeoff between speed on the one hand, and sleekness and portability on the other. The slimline models tend to be only about half as fast as the regular ones. Set your priorities accordingly.

A battery charger is a device used to put energy into a cell or rechargeable battery by forcing an electric current through it.

A simple charger works by connecting a constant DC power source to the battery being charged. If you are not very watchful, a simple charger can harm or even kill your battery by overcharging it. Timed chargers are not much better. What you really want is an intelligent charger. Yes, they do cost more, but they will save you money in the long run. Intelligent chargers monitor the battery’s voltage, temperature and/or time under charge, and determines the optimum charge current at each instant. Charging stops when a combination of the voltage, temperature and/or time indicates that the battery is fully charged.

Since Universal Serial Busses provides a five-volt power supply, it’s possible to use a USB cable as a power source for recharging batteries. Products based on this approach include chargers designed to charge standard and custom NiMH batteries with built-in USB plugs and circuitry that eliminate the need for a separate charger. Chargers may or may not have voltage regulation or filtering of the DC voltage ouput. If they have both, they tend to be called battery eliminators.

Manufacturers of mobil phones use lots of tricks to force users to stick with them, and this includes creating a wide variety of connector styles and voltages, most of which are incompatible with other manufacturers’ phones. Sometimes, even though the connector may fit, the actual charging parameters may not, which can produce an inadequate charge or even permanent damage to the device. As we have been saying in the business world ever since ancient Roman times, Caveat Emptor (let the buyer beware!). Check the specs. for the charger that interests you, and you should be just fine.

Here at Onhop.ca, we never forget who provides the money that lets us butter our parsnips;  it is you, the satisfied customer who keeps on coming back because we treated you right. We are on your side for that very good reason.

What printer should I buy, and how can I minimize printing costs?

The short answer to which kind of printer to buy is that if you mainly print photos, you should go with a color inkjet, but if you mainly print web pages, documents, spec sheets, newsletters, brochures, and graphical charts, go with a color laser, but do not forget to have a monochrome (black and white) printer on hand for non-color jobs. This advice mainly has to do with the printer’s resolution. A good laser will operate at about 600 x 600 or 1,200 x 1,200 d.p.i. (dots per inch), while a good, and fairly inexpensive inkjet can exceed 1,440 d.p.i. or possibly much, much more – up to an interpolated resolution of 24,000 x 24,000 [but see p.s. note below].

Their superior resolution give the inkjets an edge in terms of photographic detail, crispness, and clarity. Lasers are best for printing words, figures, etc., as well as a combination of text and images, with sharply delineated clarity. Let’s be as clear: if things mainly blend into each other in what you want to print, it’s best to use an inkjet, but if instead your primary print jobs consist of things that are sharply defined in distinction with each other, it’s best to use a laser.

If you do relatively little photo printing, probably it would make sense to use an online photo developing store for the little that you do print. Online photo lab costs have come down, and you can upload photos online and then pick them up at a local store or have them mailed to your home or office. Many people believe that photo lab processing produces the best quality images, and give you photographs that will not fade with time as much as those printed through either inkjet or laser processes. However, if you do have or buy a printer, chances are you will find yourself printing a lot more photos than would otherwise have been the case. This can certainly help you to become a much better photographer.

Recently, multifunction printers have made very considerable headway in the digital photo printing market, and, largely for this reason alone, multifunction color inkjets began during 2007 to outsell stand-along color inkjets, so if you print lots of pictures, check also our category of multifunction printers.

The relative costs are very hard to figure. They vary with equipment costs, paper type, what you are printing, etc. Overall, the inkjets may be just a small bit cheaper to operate, especially if you buy cartridges in bulk or do refills yourself. Laser drums last for about 40-50,000 pages, but after that a replacement drum will be quite expensive. In a way, we are comparing apples to oranges. For example, color toner cartridges usually last between 2500 and 5000 pages instead of a few hundred pages for an inkjet cartridge. A laser printer’s power consumption and heat generated are greater than occurs with an inkjet. The size and weight of the printer must be accommodated in your home or office. Still, the costs of color laser printers themselves have come down a lot in price lately, and their cost-per-print can be slightly lower, even for those using factory refills. All of this makes figuring out the overall cost factor a complicated and moving target. What you want to try to figure, of course, is the combined ongoing costs of operation and ownership, say on a yearly basis.

How can you lower your overall printing costs? Odd as it might sound at first hearing, the chances are excellent that the least expensive route to take is to have more than one printer. One size simply does not fit all. If you do a lot of both kinds of printing mentioned above, then you definitely do need both kinds of printers. If you already have a printer – again oddly enough – you can often save a lot of money just by buying a newer model. How, you might well ask, does this work? The answer is that printer manufacturers continually improve the products’ print quality and continually lower the per-page cost. Why? They simply must do this to keep their printers competitive with sending your photos or documents out to be printed. For the best color reproduction, select one of the new 6 color versions.

Now, please ask yourself a few questions:
.
1. How much total printing do I do?

2. How much of that total needs to be printed in color?

Please do not forget that black and white (monochrome) laser printers still constitute the cheapest current printing solution; the per-page cost is roughly one tenth of that of an inkjet color printer, and the black and white lasers’ printing speeds are excellent. If you mostly print termpapers or recipes or business letters, lasers do all such jobs better and much more cheaply than inkjets do. Laser printouts are water-fast, which is not true with inkjet pictures. You must keep the latter dry, or the ink will run.

3. What kind of color printing do I do most?

Are these primarily photos or just general purpose printing? If you print a lot of documents, inkjet is not the most economical way to go because you will find yourself constantly buying and replacing ink cartridges, and paying a premium for special paper.

4. Of my photographs, are some truly important, and some just OK?

Consider sending the most important photos out to a professional online processing store, and printing the rest yourself. To see reviews and prices for online photo printing, visit http://www.printrates.com/.

5. Am I printing a lot of letters and other black and white documents with a color inkjet printer?

If so, stop doing that A.S.A.P! Instead, get yourself another printer for this purpose, because right now you are spendng too much for printing, and to boot are prematurely wearing out your inkjet. You should divide up your printing so that you use the most economical printer for each specific type of job. It is almost certain that, if you do so, you will in the long run save a small fortune.

Another important point in terms of cost savings is that especially if you regularly print more of one color than another, such as a color logo on every page, then to save money you should seriously consider buying a color printer with individual ink tanks for each color. Although they may initially cost just a bit more, the economy they offer is that you only need to replace the inks you have actually used up. This alone can save you a bundle.

No one printer is ideal for all types of printing. Some are very specialized, such as thermal label printers and solid ink printers or large format printers. In many cases, the most cost effective way to handle all your printing needs is to have multiple printers installed on your computer or network. Probably the most cost effective thing you can do is to purchase a new black and white laser printer, and plan to use it for all non-color printing. Don’t wear out your more expensive and costly-to-use-color printer on monochrome jobs.

P.S. A SHORT NON-TECHNICAL NOTE ON RESOLUTION

Some manufacturers identify their printers by resolutions available through interpolation. This has created a great deal of consumer confusion. Some claim that interpolation is basically just a fraud, because if the image were really captured at, say, 19,200 x 19,200 resolution the resulting file would end up being many gigabytes in size. This represents a misunderstanding of exactly what interpolation involves, but it does help point out that by far the most important element of resolution is optical resolution. Interpolation is just an effort to add a slight embellishment to the optical resolution. Base your buying decision on optical resolution, not interpolated resolution.

In certain very limited respects, resolution actually can be improved by means of software. This process, called interpolated or maximized or optimized resolution, only adds extra dots to the image, often designed to improve color transitions. To do so, software uses algorithms [mathematical formulae] to evaluate the dots surrounding each new dot. The objective is to add solidity and, more importantly, to help determine what each particular dot’s mix of colors should be. Please understand that interpolated resolution adds absolutely no new information whatever to the image, but just adds dots and thereby makes the file larger. Interpolated resolution can, nonetheless, slightly improve the printed result. Rather than being a fraud, it is an improvement, though a minor one.

Touch screen monitors look and work like regular computer monitors, but they also recognize when and where people touch the surface of the screen. No doubt you’ve used a touch screen monitor if you’ve checked a department store bridal registry, or used an information kiosk at an airport or mall. Touch screen monitors used in combination with specially designed software make it possible for people to interact with computers in a very simple way, even if they don’t know anything about computers.

Touch input, which essentially works like a mouse, is suitable for many computing applications. You can use a touchscreen with most PC systems as easily as any other input device, such as track balls or touch pads. A touchscreen input device consists of a touch sensor, a controller card, and a software driver. This driver must be compatible with your version of Microsoft Windows or other operating system. It interprets the ‘touches’ and passes them along to specially designed software. Not free-standing, a touchscreen must be connected to a PC that is, in turn, attached to your computer network. We recommend that this particular computer, or at least this particular partition within your computer, not be used for other purposes.

Installing a touch screen monitor and its software driver is fairly simple. There is no significant advantage to buying a large size monitor. Fifteen inch touch screen monitors are probably the most common. Anyone who has experience setting-up PCs and installing software can usually setup a touch screen monitor without difficulty.

Touch screen monitors come in two varieties, resistive and capacitive. We recommend capacitive monitors. Although resistive monitors respond to any sort of touch, and the capacitive ones respond only to an ungloved finger’s touch, the latter are much more durable. Their surface is harder and better suited to the kind of un-attended, high-volume access your station may receive. You should normally go for durability.

Here at OnHop, we do not just want you to be happy with your purchase right at first, but also over the long haul. Our shopping tips are objective, honest, and oriented to the buyers’ long term best interests. That’s why we are Canada’s most highly trusted computer/consumer electronics online store.

Monitors are the computers’ windows.

They show us everything we can see of what is going oninside the computer as we work or play. One’s budget should be the primaryguide in choosing a monitor, but what type should one buy? The primary choicesare between those based upon cathode ray tubes or CRTs, and those using liquidcrystal displays or LCDs. Each has its strengths and weaknesses. If you wantthe best possible realism in the pictures displayed, buy a CRT. If you areprimarily concerned with reading text, buy an LCD.

To learn more, scroll down.CRTs

CRT technology has proven to be a very reliable and highquality standard. Television screens have been using this technology for a verylong time with great success. The process works by moving an electron beamacross the back of the screen, lighting up phosphor points on the inside of thelarge glass tube, resulting in a sharp, clear image.

Although an older technology, CRTs remain unsurpassed forthe realism of the pictures displayed, especially in terms of the contrast ratios,the depth and true rendering of colors, which are now available in themillions. If you work primarily with graphics and/or photographs and/or videos,or if you otherwise deal with color production, including any print media, thenyou will likely find a CRT to be your best bet. Likewise, CRTs remain themonitor of choice for those involved with medical imaging, and virtually anyoneinvolved in the world of art.

Although the LCDs are improving in this regard, you stillcannot get the degree of realism that a new CRT offers from even a high endLCD. Note the term NEW just used, because CRT displays do slowly degradeover time as the phosphors inside the tube gradually break down, and thoseparts are not cheap to replace.

Another advantage CRTs still have is their easyscalability to different resolutions. Resolution refers to the total number ofpixels (short for “picture elements”) that the monitor can display horizontallyx vertically. You can adjust the electron beam in the tube to lower resolutionswhile enlarging the picture and keeping its clarity intact. Conversely, asresolution goes up there is a natural tradeoff – that the image size must scaledown to permit more information to be displayed on the same-sized screen, sothere are some practical limits to the resolutions that one can view easily onvarious sized monitors.

For example, one should be highly suspicious of a 15”monitor that claims to show, say, 1,600 x 1,200 pixels. Perhaps it candeliver technically, but the image would be too small to make for readycomprehension, and so would in practice be unusable. Here are some recommendedresolutions for various sized monitors, measured diagonally from the upperright to the lower left (or vice versa). Multiply the horizontal pixelstimes the vertical pixels to get the total number of picture elements used todraw the screen, e.g., 800 x 600 = 480,000 pixels.

15” – 800 x 600 to 1,024 x 768 pixels 

17” – 1,280 x 1024 pixels

19” – 1,280 x 1,024 pixels

21” – 1,600 x 1,200 pixels

23” – 1,768 x 992 to 1,920 x 1,080 pixels

25” – 1,920 x 1,440 pixels

27” – 2,048 x 1,536 pixels

Please bear in mind that your monitor must match thecomputer’s video card. It should be capable of displaying the resolutionsand colors that the adapter can produce. Conversely, if your monitor is capableof displaying resolutions much higher than the card can generate, you will getonly what the card can produce, not what the monitor could show with a bettervideo card. Any mismatch between the monitor and the video card will addup to money wasted.

Relatively flat screen CRTs are now the standard. FlatCRTs are designed to reduce the glare and distortion created by conventionalCRT monitors. The flat tube increases image clarity while reducing glare fromlight sources within the room. Nonetheless, you will still likely need to buy aglare reduction screen cover. Consider it an essential part of your CRTmonitor.

Also, CRTs offer a much larger viewing angle as opposedto LCDs, which is especially important when more than one person is viewing thescreen, as when you want to use the monitor in conjunction with a homeentertainment centre. Another advantage is the CRT’s extremely fastrefresh rate, typically 70-85 hertz or cycles per second. This refers to howquickly a pixel can turn on and off. If this rate is low, fast motion willappear blurred, or even leave “trails.”

Try to ensure that your CRTmonitor supports refresh rates above 70 Hz; anything less approaches the ACpower frequency of 60 Hz. Low refresh rates result in screen flicker and causeeye strain. If you use your monitor more than a few minutes a day, simplydon’t go there.

The distance between pixels iscalled dot pitch, and is measured in millimeters. The distance between pixelshas a lot to do with the quality of the image. CRTs come with a range of dotpitches. If the one you are considering is above .28 mm, we’d suggest,again, just don’t go there. You want and need a monitor with a dot pitchof .28 or preferably less.

Another “don’t gothere” concerns the interlacing/non-inter-lacing issue. If the scanningbeam hits each and every line of pixels in succession, on each pass, themonitor is non-interlaced. The interlaced monitor scans the odd numbered lineson one pass, and then it scans the even lines on the second pass. This resultsin an almost imperceivable flicker, which will eventually result in eye-strain,blurred vision, sore eyes, headaches and perhaps even nausea. Make sure the CRTyou are considering is non-interlaced. Avoidinterlaced monitors like the bubonic plague.

When buying a computer monitor for your home, consider where it will beplaced. Should desk space be an issue you’ll want to choose an LCDdisplay with a small footprint that will easily leave enough room on your deskfor a keyboard and mouse pad. Like to watch DVD movies? You can save space inyour home by watching them on your computer monitor instead of on a TV. If thisinterests you be sure to buy the largest-sized screen you can afford.

The CRT’s disadvantages must of course include its bulkiness andweight. This is not a highly mobile computer peripheral. Another disadvantagefor those who use the monitor hour after hour is glare. While glare can beminimized through adjusting the set, it can only be wholly corrected with ananti-glare shield, which is an extra cost that should definitely befactored into a decision to buy a CRT. In terms of the long term costs of themonitor, a clear disadvantage is the much greater powerconsumption of CRTs as compared with the other technologies. To minimize this, set the screen saver to come on rather quickly, andconsider skipping the fancy screen saver programs; a blank screen while you areaway will do quite nicely. A final disadvantage, which in the midst of aCanadian winter can be quite welcome, is that they generate, store anddisseminate a lot of heat.

LCDs

This is the newish technology,and like any other it’s sexy and cool. LCDs are some 80% less bulky thanCRTs, and commensurately lighter, and therefore much more portable; in fact,virtually all laptops and notebooks have them. The latest high end LCDs havecrisp image quality and are easy on the eyes. A primary advantage they haveover CRTs will interest anyone who works primarily with text. That is, thepixels you find on LCDs have nicely defined edges – and this producessharp and well-focused letters on the screen. If you are a writer, editor,proof-reader, etc., your best bet is a LCD.

LCDs have almost closedsome of the gap with the CRTs in color rendering, especially at the high costend, and of course the size and weight differences are huge. LCD screenstend to cause less eye fatigue and strain than CRTs without anti-glare screens.The LCDs are immensely more energy efficient, being  an almostcostless part to operate. The energy savings may not be much for an individualuser, but if you are looking at a corporate office where 50 displays are inuse, the energy savings might be more of an issue.

LCDs vary considerably intheir response times, the speed with which they can turn pixels on, then off,then on again. Older and budget LCDs are so slow that they badly blur moviesand fast action games. Although the gap is lessening, for many LCD monitors, especiallyat the low end, there is reduced color clarity as compared with CRTs. This isbecause the technology involves different ways to deal with the problem of lowresponse times that are essentially “work arounds” rather than true solutions.For general use, get a monitor up to 24” with a response time of 16milliseconds or less. For gamers, people using multimedia and colorprofessionals, a response time of 12 milliseconds is the minimum. For hard-coregamers and video professionals, Look for a response time of 8 milliseconds orless.

There are two distinct typesof LCD technology available today: active matrix and passive matrix. Thepreferred format is the active matrix, which uses a TFT (thin film transmitter)to produce a more secure picture with a relatively wide angle of view. TFTprovides the best resolution of all of the flat panel technologies, but it’salso the most expensive. There is enough difference in these formats that wecan decisively say with respect to the passive matrix, just don’t go there.Manufacturers are slowly phasing out passive matrix technology, due to its slowresponse time and overall lackluster performance.

LCDs offer two aspect ratios:standard format (4:3) or widescreen format (16:9 or 16:10). This onlinecomputer store recommends widescreen, because it allows you to view multiplewindows side-by-side, and thereby see more of what you are writing or workingon, or else to work with more than one application. Also, the widescreen formatis taking over with high definition TVs, DVD movies, etc., so one might as wellmove with the times. Your monitor will likely last for a long time, and thewidescreen format has already virtually arrived.

As is especially obvious withnotebooks, because LCDs use polarized pixels, the effective viewing angle(technically, the viewing direction) can be quite narrow. This means that onemust be pretty much directly in front of the screen to see anything clearly.This also means that one will often need to have a very highly adjustable standto support the monitor, which should be factored in as an additional cost.

LCD monitors are not all created equal. PVA (patterned vertical alignment) andS-PVA (super patterned vertical alignment) are alternative versions of MVAtechnology, and some have a very high contrast ratios such as 3000:1. PVA panels all use at least true 8-bitcolor electronics and do not use any color simulation methods. SomeS-PVA panels use even 10-bit color internally, which enables gamma and othercorrections without banding. PVA and S-PVA can offer good blackdepth, wide viewing angles and S-PVA can offer additionally fast response timesthanks to modern RTC technologies. At the moment, PVA and S-PVA monitors arethe only LCDs that offer a wide viewing angle. Unfortunately, they usually cost about 30 per cent more than the others, so  in this case you do get what you pay for.

Sometimes MVA and PVA type displays are categorized as VA type displays.

LCD monitors have a disadvantage compared with CRTs inthat they can only function effectively at their “native” resolution. Thescreen can truly display only the number of pixels in its matrix, no more, noless. It can “display” a lower resolution, either by using a fraction of theavailable pixels, or by blending multiple pixels together to simulate a singlesmaller pixel. Either way, you get blurry or fuzzy images, especially withtext, so plan to leave your LCD set at its native resolution. A potentialproblem is that if your graphics card does not support thedisplay’s native resolution, you may get poor quality images or perhaps noimages at all, so check this out before you part with your monitor dollars.

Because each LCD pixel isseparately driven, one can have individual defective pixels that are eitherstuck on or else are dead. The computer industry has never fully agreed [ISO13406-2 notwithstanding] on the maximum acceptable number of defective pixels.In practice, a SVGA LCD panel with 4 defective pixels is usually considereddefective, and customers should request an exchange for a new one, especiallyif the defective pixels are close together or near the center of the screen.Some manufacturers now have a “zero defective pixel guarantee,” and willreplace such screens for free.

LCD panels also may have ordevelop defects known as Mura, which look like small-scale crackswith very small changes in luminance or color. Consumers should reject such ascreen.

As Wikipedia tells us:“Although LCDs typically have more vibrant images and better “real world”contrast ratios (the ability to maintain contrast and variation of color inbright environments) than CRTs, they do have lower contrast ratios than CRTs interms of how deep their blacks are. A contrast ratio is the difference betweena completely on (white) and off (black) pixel. Also, LCDs can have‘blacklight bleed” where light (usually seen around corners of the screenleaks out and turns black into gray.” Another problem that Wikipedia notesis that “Some LCD monitors can cause migraines and eyestrain problems due toflicker from florescent backlights fed at 50 or 60 Hz. “

Typically, brightness is not aconcern with CRT monitors, but because LCD monitors are backlit they havedifferent brightness levels. The brightness rating for an LCD is commonlyreferred to as ‘nits’ and it commonly ranges from 70 to 250 nits. The higherthe nits, the brighter the display.

The Bottom Line

Unfortunately the industry is very poor about properly listing thespecifications for monitors to help buyers understand and compare them. At agiven resolution, there is virtually no cost difference between CRTs and LCDs.The many announcements of the death of the CRT are slightly exaggerated.However, if you choose to buy a CRT online, bear in mind that they are bulkyand heavy, which makes them expensive to ship. The massive and ongoingmove toward buying from online computer stores is driving a lot of people towardLCDs, mainly for this reason.

Manufacturers add bells andwhistles to help sell their products. Some features, like media card readersand USB hubs are nice to have but not always necessary. Others, such asmultiple video inputs, are much more necessary. Most monitors have at least twovideo inputs, usually a VGA-style (analog) connection and a DVI (digital)connection; these will meet the needs for most users. Some monitors alsosupport the newer HDMI connection. If you plan to watch high definition content,make sure that the DVI and/or HDMI connections are “HDCP-compliant.”It is also of fundamental importance that the monitor stand should besufficiently adjustable to meet your ergonomic needs. Make sure that anysoftware needed to setup or control the monitor will be included in themonitor’s cost.

Generally avoid bundledcomputer deals that include a monitor, because the majority of such dealsbundle in whatever is left over in stock, last year’s model, or a no-nameloss-leader brand with poor specifications.

Warranties range from 90 daysto one year. Read the fine print.

Do not be dazzled by extras,such as USB cards and built-in speakers. When shopping for a monitor, alwaysbear in mind that the most important thing you are seeking is image quality, pure and simple. Even ifyou actually buy  from an online store to save money (and usually you willsave a lot), go to a local store to check out with your own eyes which modelsdeliver the best image quality. You can always add extras, but you cannotincrease the monitor’s basic performance. 

Computer projectors cast a greatly enlarged version of the computer screen onto a movie screen, or even a clear white wall.

The bad news about computer projectors is that they are costly; the good news is that prices are falling.Some are designed to be used in conjunction with home theatre systems.Others are education or business-oriented. Typically, you would use oneof the latter to help you illustrate a talk, or to convey informationin conjunction with a lecture or speech or talk before a medium orlarge audience. A multimedia projector can project images from varioussources, such as a DVD player or laptop computer. Multimedia projectorscan produce such good video quality that many people are replacingtheir TVs with a projector and screen for an enhanced home theaterexperience. Multimedia projectors come in three types: Cathode Ray Tube(CRT), Liquid Crystal Display (LCD) and Digital Light Processing (DLP).

CRT projectorsemit images like a TV, consisting of red, green and blue light. Theycost nearly twice the price of LCD and DLP projectors. CRT projectionsshould be used in dark rooms; otherwise light will overwhelm the image.They’re big, bulky and hard to move. They can be costly to maintain; ifone of the color tubes fails, you will need to replace all three.However, their images are crisp at any resolution and have a full rangeof colors, including the blackest blacks, and they provide the mostauthentic cinematic movie experience.

LCD projectorsproject light images through small, transparent panels. They’re smallerand more portable than CRT projectors. To use such a projector for hometheater, be sure to shop for one designated specifically for hometheater use. Less expensive office models tend to have lowerresolutions.

LCD projectors are much cheaper thanCRT projectors. LCD projectors put light through tiny pixels onto a bigscreen, and the image can sometimes look pixilated or blocky, as thoughyou are viewing it through a screen door. If a pixel burns out itwill display as a black or white dot on the screen and the only way tofix this is to replace the whole chip. An LCD Projector’s imageresolution is limited by how many pixels its chip has. If it has only a1024×768 resolution chip and you are watching high definition TV, theimage will be less sharp and detailed than that from a CRT projector.They produce a fan noise, and you must replace the light source aftereach 1,000-2,000 hours of use. They’re compact, lightweight andhighly portable, and their power consumption is low. They produce goodcolors, high contrast, and high image quality in partially lit rooms.

DLP projectorsemit light through a transparent chip onto a tiny mirror array, whichgives good quality, high definition images. However, they suffer fromhaving a fixed resolution like LCD projectors. They need a replacementlight source about every 1,000 hours to keep images sharp, but theywork for both office and home theater use and do not suffer “screendoor effects” like LCD projectors. DLP projectors are just slightlymore expensive than LCD projectors. They use little energy to producehigh quality images with vivid colors and high contrast, even inpartially lit rooms. They’re more durable than LCD projectors.

Before buying, you need to answer six important questions:

Which aspect ratio do you want?Aspect ratio is the width-to-height relationship. Movies made before1953 used a ratio of 4:3, while the current HDTV standard is 16:9, andtoday there is considerable interest in the dedicated super-widescreenratio of 2.35:1. If you like to watch the Oldies, choose 4:3, if youwant to be with it today, choose 16:9. If you are captivated by HDTV orfuture oriented, choose 2.35:1. There are some compromise in/betweenratios, but why compromise?

What resolution is best for you?A projector’s resolution is the number of pixels it has available tocreate an image, the higher the better, but the more costly theprojector will be. If you can afford it, make sure that the nativeresolution of the projector matches the native resolution of yourcomputer. The currently most popular home theatre resolution is 1280 x720, and for most people it is probably the best value-for-money choicetoday.

How bright should it be? Forhome theatre applications, 2,000 lumens may be quite enough, but forbusiness applications, if you want to make presentations withoutturning the lights down, get a projector with at least 2,000lumens and preferably a good bit more. Don’t be fooled by somemanufacturers who overstate the lumen ratings of their machines; readobjective lab testing reviews.

How much contrast do you need?The contrast ratio relates to the relationship between brightness anddarkness. Many LCD projectors have a contrast ratio of 400:1, whichmeans that the lumen output of a projected white image is 400 timesgreater than that of a projected black image. This is enough, but justbarely. If your eyesight is less than normal, get more if you canafford it.

What are your installation constraints?If you get a CRT model, plan to stick it somewhere and leave it there,and plan simply to rent another type model for specific meetings/talks,etc. Meeting venues often have their own units, which you can simplyrequisition, but check in advance to make sure. The LCD and DLP modelsare portable, and can be hauled out for educational or business use,and then brought back home.

What will it cost?There is a fairly wide range here, from under $300 to more than $2,300,so these items are sufficiently costly that you should first read someassessments by neutral and objective reviewers.

• There are many online sources of this information, such as Consumer Reports (www.ConsumerReports.org). You can access free Consumer Reports online courtesy of your local library (www.accessmylibrary.com). Also you can consult the Consumers’ Web Watch (www.consumerwebwatch.org), the Consumers’ Union (www.consumersunion.org), and the Consumer Electronics Net (http://www.consumerelectronicsnet.com/). You can find slightly more technical but still objective reviews at http://www.CNET.com, http://www.PCWorld.com, http://www.ZDNet.com, and http://www.???.com (Tom’s Hardware Guide).

Here are some suggested requirements for a home theater projector, if you can afford them:

Projector Type: LCDNative Resolution: XGA 1024 x 768Maximum Resolution: UXGA 1600 X 1200Brightness: 2000 lumensHDTV Projector: HD ReadyAspect Ratio(s): 4:3, 16:9Projection Distance: 3 - 35 ftContrast Ratio: 400:1Horizontal Frequency: 15 - 91 KHzPrice: Starting around $800

Business Presentations DLP projectorswork well and are portable for multimedia (text, graphics and video)presentations. Buy (or rent) a unit with built-in audio and a remotecontrol. Make sure it is lightweight (3-8 lbs.) since you will alsohave a carrying case and cables. Most multimedia projectors arePlug-and-Play, but be sure the model you are considering will work withyour PC’s operating system. Some projectors are not Mac-compatible or may require extra software to work with a Mac.

Here are suggested requirements for a multimedia business projector, again if you can afford them:

Projector Type: DLPNative Resolution: XGA 1024 x 768Maximum Resolution: UXGA 1600 X 1200Brightness: 2000 lumens or preferably betterHDTV Projector: HD ReadyAspect Ratio: 4:3Projection Distance: 4 - 24 ftContrast Ratio: 2000:1Horizontal Frequency: 15 - 80 KHzPrice: Starting around $1,500

p.s., A computer projector glossary can help you understand the lingo concerning these machines.A good one resides at: http://www.avpartner.com/Glossary.aspx

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