Video Projector Survival Guide

There are about as many different opinions about video projectors as there are video projectors. There are so many different kinds, it can be hard to make sense out of it.

I’m not going to discuss business projectors. This is for the home theatre enthusiast who is looking for their first real projector. Business, sanctuary, and other application are discussed elsewhere in this section.

So let’s start with the basics:

4:3 or 16:9?

These numbers reference the native aspect ratio of the projector: NTSC (4:3) or widescreen High Definition (16:9). The first number refers to the width of the projected image, and the second, smaller number, to the height. These numbers define a relationship – for every 16 inches wide, the screen is 9 inches tall, for example. Substitute feet, millimetres, whatever you’d like – you still define a rectangular box. You may also see aspect ratios as a number, say, 1.33 for NTSC. Divide 4 into 3 and you get 1.33. Same for 16:9. It’s also referred to as 1.78.

4:3 is what we are used to watching. More square than rectangular, it provides for limited vistas. The infamous term “pan and scan” is derived from floating a 4:3 window over a widescreen movie. You don’t see the full picture.

16:9 is a convenient dimension for a display. It provides for a more panoramic scene, and allows directors more territory on-screen. Most DVDs are now encoded for widescreen (16:9 and up!), and all HDTV is 16:9.  Get used to it folks. It’s here to stay.

Any decent projector will switch between 4:3 or 16:9. So that takes care of that, right?  No. A 4:3 projector switches to 16:9 by turning off pixel rows at the top and bottom of the picture. I won’t bore you with the math, but your 4:3 projector set for 16:9 is working at about 2/3 of its optimal brightness and resolution. That’s a problem. Widescreen material, like HD and DVD movies, are made and transmitted at much higher resolutions than 4:3 is capable of, so when you want the best picture, you’re using only 2/3 of what the projector was is capable of.

The same is true when watching 4:3 material on a native 16:9 projector, but because 4:3 source material (“actual” pixels 640x480) is a lower resolution than 16:9, the only thing you really lose is a little brightness. Considering that 4:3 is on the way out (really out, not out in a Paisley shirt kind of way), it’s an acceptable sacrifice.

DLP or LCD?

This is where most of the confusion lies – everyone has a favourite. I won’t tell you what is “better”. It’s a personal choice, based on many subjective factors. What I will tell you is that, in my experience, while DLP may well be the outright better technology for all applications, that day is still in the future.  There are some very interesting developments on the way from the LCD guys, so keep your eyes peeled.

LCD:  Liquid Crystal Display. A current is passed through a crystallized organic compound, changing its shape on a molecular level. Zap them, and the crystal molecules change their shape, allowing red, green, or blue light to pass. On moderate to mid-range priced projectors, you get better bang for the buck from LCD. LCD colours tend to jump out at you more, and tend to be richer and more vibrant. Because there has to be a physical separation between pixels, LCD projectors can suffer from a “screen-door” effect. It’s referred to as this because it can be like looking out a screen door; everything is divided into little squares separated by a thin black line. The screen-door effect of modern LCD projectors has been minimized – the pixels are much closer together than previous versions.

Eventually, all that molecular shape changing takes its toll – the crystals begin to react slowly, or may even break. This means that eventually, your LCD projector will age, the liquid crystal becoming so unresponsive that the panels become useless. The organic compounds the liquid crystals are made from will also eventually discolour and burn with exposure to bright light, turning yellow with time. While this is a fact of life, it takes an incredibly long time to achieve, years of operation, so shouldn’t really concern you.

DLP:  Digital Light Processing. White light is shone through a spinning colour wheel (red, green and blue). The coloured light is bounced off a panel made of millions of micro mirrors, then from the mirrors through a lens assembly. The chief advantage of DLP is texture. Because of how it works, there literally is no space between pixels on a DLP projector, and as a result, no screen-door. Colour has been improving as well, and on more expensive DLP projectors, colour accuracy and intensity surpass even the best LCD projectors. The chief liability of DLP is the spinning colour wheel. Less expensive DLP units spin the colour wheel at a lower speed (2x) than more expensive chips (4x and above). This can result in a disconcerting colour oscillation (aka “The Rainbow Effect”) that is very uncomfortable for some people. Again, the effect is minimal on higher end, faster spinning, DLP chips.

DLP colour wheels are often segmented. This improves the performance of the chip by increasing the effective speed the wheel spins at, thusly increasing the speed at which the colours are refreshed. We recommend avoiding 2x or 2 segment colour wheels particularly, as these tend to be most prone to the Rainbow Effect. These chips tend to be found in entry-level DLP projectors. Opting for a 4x or better, while costing more money, significantly reduces the possibility that your movie or presentation will give your audience a headache.

So there’s no clear winner in DLP vs. LCD – they both have significant strengths and weaknesses. A good rule of thumb? LCD for low to mid-range units, and DLP for higher end installations.

What the heck do all those numbers mean?

There’s a lot of numbers associated with video projectors. Here is a brief rundown of what they mean and why they’re important.

ANSI Lumens – Dictionary.com defines “lumen” as “Abbr. lm Physics. The unit of luminous flux in the International System, equal to the amount of light given out through a solid angle by a source of one candela intensity radiating equally in all directions.”  Essentially, this means that a lumen is the measurement of light given out by one candle at a distance of one foot. Obviously, you need a lot of candles to create a lot of light. ANSI stands for “American National Standards Institute”, the governing body over such things as measuring actual light output. Before ANSI standards, projector brightness was measured at the center of the projected image, with significant drop-off toward the edges. The newer ANSI standard breaks the screen into 9 parts, with brightness being measured as an average over the entire surface of the projected image, instead of just at the middle.

Is brighter better? Not necessarily. Most home theater projectors max out at 1000 ANSI Lumens or so, while a decent business projector is twice that, or more. The difference is because the people who design these projectors have determined that you have more control over ambient light in your home. You don’t have to compensate for a wall of windows in a boardroom, or keeping the lights on so you can scribble notes. Instead, you’re probably trying to replicate the kind of experience you get in a movie theatre. Psychologically, we’re more likely to be immersed in an image that isn’t competing with other visual distractions. Dimming the light levels on all other objects in our field of view, other than the screen, actually improves our perception of it.

Resolution – The actual number of pixels, or individual picture elements, measured in columns and rows. Resolution will vary, on a 16:9 projector, generally from 850x480, 1024x576, to 1280x720. Note that while the actual pixel numbers change, the ratio remains the same – 16:9. Pixels are arranged in a grid like pattern. The larger number is the left to right pixel count, the smaller number is the top to bottom. The higher the resolution, the greater the detail (or so it would seem… see “Contrast”, below). True HD starts at 1280x720, and goes all the way to 1920x1080. A home theater purist would probably opt for the native 1280x720 display, other considerations not withstanding. This is a big thing right now in the HT crowd: pixel matching. One pixel on the source image equals one pixel in your home. I personally won’t say that you’ll get a “better” picture pixel matching. IMHO there are too many other important factors that go into creating a bright, vibrant, beautiful picture.

Contrast Ratio – The most important number associated with projector performance, and also the most misunderstood. Simply put, contrast ratio is the relationship between the brightest and darkest point of a given image, measured in discreet steps. The farther apart the numbers are, the greater the detail in the darker areas. As a result, larger contrast ratios imply better picture.

Now, this is where it gets tricky… remember that brightness measurements are standardized, largely as a result of poor practices by projector manufacturers of the past, in rating the brightness of their projectors. Currently, contrast measurements are not standardized – everybody uses methods and formulae that are advantageous to them. As a result, ignore this number. It’s not a good indication of projector performance, and won’t be until everybody starts using the same methods. To illustrate, the Da-Lite Screen Company, suggests “… the contrast of the page before you is about 80:1. If you are looking at them on a monitor, the ratio is closer to 50:1. If you go to the movies and watch a good, clean print, the ratio, given the right scene, might be 500:1.” (“Angles of View”, Volume III, Contrast – From Dark to Light)

Throw Distance – Indicates the minimum and maximum distance between the projector and the screen. Don’t rely overmuch on these numbers. The idea is to achieve the largest possible picture (which is a function of throw distance) while retaining excellent picture characteristics, like brightness, colour saturation, etc. Rather than using these numbers, consult with an AV professional who can help you determine what image size, and projector location, will work best for you.

Bottom line? It’s not all about the numbers. They only tell you so much, and in certain cases, like contrast ratio, they tell you very little. I’ve seen projectors that, on paper, aren’t particularly impressive, but get them out of the box and playing a movie, they really shine. Pun intended.

How much should I spend? Where do I go?

You don’t have to spend a fortune. Video projectors, compared to other display technologies, are the best value per square inch, bar none. Consider the automobile: the more you spend, generally, the “better” the car is. But, with projectors, like cars, you get to a point of diminishing returns – for a 2% increase in performance, you have to spend twice as much. The trick is to have a clear idea of what you want you’re comfortable spending. I advise people to determine what kind of home theatre enthusiast they are, and budget accordingly. Currently, a top of the line home theatre video projector will run about $8000, while an entry level unit will cost about $1500 or less. They’re both excellent value, but clearly the more expensive unit projects a better picture. Is it worth the extra $6500? Tough call. One customer of ours said he was looking for an “…experience like having King Kong looking through a window”. Believe it or not, it doesn’t have to cost much to achieve that kind of experience.

Find a knowledgeable sales rep, someone who understands the technology and how you interface with it. You average run of the mill salesperson knows only what he / she has been told, and as a result, may not have your best interests at heart. You can find excellent deals on-line, but while you get lower prices, you don’t actually see the unit you’ve bought until it’s delivered. This makes dealing with a knowledgeable sales person doubly important. This can be complex stuff. The right person can go a long way to making sure that your money is well spent. Box stores can be an exercise in frustration. Minimum wage and a commission don’t add generally up to an easy experience. You may end up paying an inflated price for something you could have paid a lot less for on-line, or even worse, get the entirely wrong unit.

Specialty stores deserve a mention here as well. You know them – the bright buildings with bars on all the windows. Here, while you’ll pay more, your sales person will likely know more about the gear than your average joe, and will help make the experience a productive, albeit expensive, one.

Many people end up educating themselves, and as a result, a surprising number will actually buy a projector without actually ever having seen it in action. Others will rely entirely on the expertise of their sales person to recommend something that will meet or beat expectations.  Talk to your rep, find out what they know. Ask why they like a particular unit, why they’re recommending it. Finding a technically savvy salesperson, regardless of where you spend your money, is the first step in making your home theatre dreams come true.

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