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4:3 vs. 16:9 -- What is the best solution?

Evan Powell, November 21, 2001

The good news is that setting up the projector like this lets you use 100% of the display device for 4:3 images (all 768 lines of an XGA machine). However, be aware that setting up like this doubles the brightness of the image on the screen for your 4:3 material. Why? In 16:9, your screen area is 33% greater than the 4:3 area. So light per square foot is increased by 1/3 when you reduce the image size from 16:9 to 4:3 while maintaining the same picture height. Furthermore, in 4:3, you are using all of the light output of the projector rather than the 75% you use in 16:9 (the remaining 25% is that which is blocked by the black bars). The net result is that your projector is throwing about twice the amount of light per square foot onto the screen. This may or may not be an issue for you, but it is something to be aware of.

A second option for displaying a 4:3 image on a 16:9 screen is to use the electronic formatting option available on many projectors, and/or on your sources. You can leave the lens set where it is for 16:9, and you can simply select the option that positions a scaled down 4:3 image in the middle of the screen with bars on the side. When you do this, illumination per square foot remains unchanged. However you are now using half the number of pixels to produce your 4:3 image than you would if you had used the zoom feature. Basically, in this mode you are using half the resolution and half the brightness that the projector is capable of delivering in full 4:3 operation.

There is a downside to electronically reformatting from your sources, and it's a biggie: you often get gray side-bars, or pillars as some people call them. Gray bars are an unfortunate solution to a technical problem--they are delivered as part of the signal to prevent uneven burn-in on CRT-based 16:9 TVs. Though gray side bars help preserve CRTs they have NO benefit whatsoever for digital projectors since they are not subject to burn-in problems.

I say this is an unfortunate solution because the easiest way to destroy the impact of a video image is to surround it with gray bars. No art museum in the world would ever present an Ansel Adams exhibit with his photographs mounted in gray frames. There is a good reason for this-neutral gray is what you are trying to get away from-crisp black and white contrast is the objective. And it's the same for video.

Do you want to do ONE thing to vastly improve the dramatic impact of your home theater? Then forget about the projector, forget about the screen material, forget about your sources. Instead, take steps to ensure that the video images you watch are always displayed in a SOLID BLACK FRAME. Unless you do this, your picture will always look anemic compared to what it would otherwise.

How do you do this? With electric masking on the screen, that's how. Electric masks are black panels that open and close at your command, either horizontally from the top and bottom, vertically along the sides, or both, based upon the actual size of the image you are viewing. In the context of the present discussion, if you have a 16:9 screen with a 4:3 image in the middle of it, masking can be deployed to cut off the gray side-bars and give you a black frame around your active image.

On a 16:9 screen, the ideal solution is four-way masking. The reason is that you want to mask a 4:3 image in the center of the screen with side masks. You retract all masks for 16:9 material that fits the full frame. And you want to close the top and bottom masks to create a frame on movies that are wider than 16:9. Four-way masking is the most expensive set-up of course. But you need it IF you have a 16:9 format screen and a desire to put a solid black frame around all material that you watch. Conversely, a 4:3 format screen needs only two-way (top/bottom) masking to accomplish the same thing. For many folks, this may be a good reason to consider a 4:3 format screen as we will discuss below.

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Screen Option One
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Anamorphic Lenses
Contents: Introduction Screen Option One Option One Continued Anamorphic Lenses
  Screen Option Two No Right Solution Screen Option Three Conclusion