When you are buying projector screens or displays, you would have heard the salesman talk about their aspect ratios, such as 16:9 and 4:3. Aspect ratios are the ratios between the width and height of images.
When a salesman is talking about aspect ratios of video and data projectors, he/she is telling you about their native aspect ratio – which is the ratio of the Digital Light Processing (DLP) chip or LCD panels.
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The vast majority of projectors available on the market are capable of displaying different aspect ratios. However, if you want the best results when using your projector, you need to use the native aspect ratio, which is the aspect ratio in the projector's default setting without manipulation.
Let’s quickly cover the two most popular aspect ratios of the various video and data projectors.
4:3 Video or Standard format
The most common native aspect ratio in data projectors is 4:3 aspect ratio - XGA projectors use this aspect ratio. You pronounce 4:3 as “Four three”, “Four to three” or “Four by three.” The majority of computer monitors and CRT televisions come with this format. When the ratio is 4:3, it means that the image width and height are four and three units respectively.
16:9 Widescreen format
Home cinema projectors native aspect ratio is 16:9 - HD, Full HD and 1080P projectors use this ratio. 16:9 is pronounced as “Sixteen nine”, “Sixteen to nine” or “Sixteen by nine.” Few computer screens and most of the new televisions on the market have 16:9 as their native aspect ratio. 16:9 means that the image width and height are 16 and 9 units respectively.
When talking about various native aspect ratios, it is the physical property of LCD panels and DLP chips. Although there is a distinction between image aspect ratio and native aspect ratio, most modern projectors are capable of displaying both the aspect ratios.
The projectors will digitally convert the aspect ratio, based on how you like it. However, when you use an aspect ratio which isn’t the native aspect ratio, you are not using your projector to its complete potential.
What happens when you use a native 4:3 projector to project 16:9 image?
When you use a native 4:3 projector to project 16:9 images, the entire 16:9 image will be visible on the screen. However, there will be large black borders at the bottom and top of the image. Overall, the projector will display the 16:9 image as a 4:3 image.
What happens when you use 16:9 projector to project 4:3 image?
When you use 16:9 projector to project 4:3 image, you will see the complete 4:3 image on the screen. Although the aspect ratio is 16:9, you will observe that there are huge black borders on both sides of the projected image.
What aspect ratio should you use?
The aspect ratio you use depends on the equipment and application you use with the projector. If you are using the projector to watch movies, the native aspect ratio is generally 16:9 or now even 16:10 for widescreen format.
If you want to use the projector for business purposes, you can use 4:3 format or 16:9 format as new laptops and notebooks come with the widescreen format. Generally, the 4:3 or XGA projectors are more cost effective and used in schools and boardrooms where budget is an important aspect.