The Projector Specialist

National Sales Line

1300 88 11 79

Adelaide

Brisbane

Melbourne

 

(08) 64677744

(07) 33332744

(03) 90956744

Perth

Sydney

 

(08) 64677744

(02) 80042744

ProjectorsScreensLampsAccessories
    GoTo UK Projector Site

The Australian Projector Specialist

 

Home |  Contact |  FAQ |  Projector Guide | Add Projectisle to your projector links Short List View Cart

 

Resolution

_____________________________________________________________________

track

 

Simply defined, "resolution" refers to the number of lines of picture image displayed on screen. The greater the resolution, the greater the picture quality. For example, a standard TV signal displayed on a standard TV set consists of 480 lines of resolution. HDTV (high-definition) signals, on the other hand, contain more than 700 lines -- hence their superior quality.

 

Native Resolution

 

Portable home-theatre LCD and DLP projectors both come in different "fixed" resolutions. That is, every projector has a set maximum resolution it can display, this is set by the internal LCD or DLP panel and is called the Native resolution. A projector's Native resolution rarely matches the exact resolution of the incoming signal. Therefore, the projector must first resize the signal's image internally, through scaling, to map it onto its own fixed-resolution LCD or DLP panel.

 

There are projectors that offer flexibility between WXGA and XGA by offering a hybrid resolution of 1280 x 768 - widescreen (16:9 WXGA aspect) width of 1280 by video (4:3 XGA aspect) height of 768. this offers flexibility between these aspect ratios without scaling of the signal giving the pure image.

 

 

What are wvga, svga, wsvga, xga, wxga, sxga and wuxga?

 

These are the main standards of resolution. The resolution is the number of 'pixels' that the projector is capable of displaying. Pixels are the dots that make up the image on your screen.

SVGA, XGA, SXGA and UXGA are terms that describe common resolutions used by computers and projectors. The table below shows you the number of pixels that are displayed in each common resolution and the resolutions of a 16:9 image on a 4:3 native aspect ratio projectors and a 4:3 image on a native 16:9 projector.

VGA SVGA XGA SXGA UXGA

Pixel Count Comparison

Resolution

(native)

Pixels

(H x V)

Total Pixels

Increase over VGA
VGA 640 x 480 307 200  
WVGA (4:3 image) 640 x 480 307 200 1.00
SVGA (16:9 image) 800 x 450 360 000 1.17
WVGA 854 x 480 409 920 1.33
WSVGA (4:3 image) 725 x 600 435 000 1.42
SVGA 800 x 600 480 000 1.56
WSVGA 964 x 544 524 416 1.71
 XGA (16:9 image) 1024 x 576 589 824 1.92
WXGA (video)(4:3 image) 960 x 720 691 200 2.25
XGA 1024 x 768 786 432 2.56
WXGA (data)(4:3 image) 1066 x 800 852 800 2.78
WXGA (data)(16:9 image) 1280 x 720 921 600 3.00
WXGA (video) 1280 x 720 921 600 3.00
SXGA (16:9 image) 1280 x 720 921 600 3.00
WXGA (data) 1280 x 800 1 024 000 3.33
SXGA 1280 x 1024 1 310 720 4.27
SXGA+ (16:9 image) 1400 x 960 1 344 000 4.38
UXGA (16:9 image) 1600 x 900 1 440 000 4.69
SXGA+ 1400 x 1050 1 470 000 4.79
WUXGA  (4:3 image) 1440 x 1080 1 555 200 5.06
UXGA 1600 x 1200 1 920 000 6.25
WUXGA 1920 x 1080 2 073 600 6.75
QXGA 2048 x 1536 3 145 728 10.24
WQXGA 2560 x 1600 4 096 000 13.33
QSXGA 2560 x 2048 5 242 880 17.06
WQSXGA 3200 x 2048 6 553 600 21.33
QUXGA 3200 x 2400 7 680 000 25
WQUXGA 3840 x 2400 9 216 000 30
4K2K 4096 x 2400 9 830 400 32.00
8K4K 8192 x 4320 35 389 440 115.20


 

 

 

This first graphic shows to scale, how resolutions compare for widescreen (16:9) Home Cinema  projectors and a Video (4:3) projector in 16:9 aspect ratio mode:p>

 

projector widescreen resolution comparisons

 

This next graphic shows to scale, the difference between all the Video (4:3) projector resolutions:

 

  projector guide to 4:3 aspect ratio resolutions

 

Input Signal Resolutions?

 

You may have noticed that our projector specifications state 1080i, 720p etc under Compatibility - HDTV but what are they? Separating the number from the letter "1080" refers to the vertical resolution 1080 pixels and the "i" refers to the signal being Interlaced ("p" is for progressive scan). Other signals are: 

 

Signal Resolution Scan Definition
1080p 1920 x 1080 Progressive High
1080i 1920 x 1080 Interlaced High
720p 1280 x 720 Progressive High
720i 1280 x 720 Interlaced High
576p 720 x 576 Progressive Standard
576i 720 x 576 Interlaced Standard
480p 640 x 480 Progressive Standard
480i 640 x 480 Interlaced Standard

 

How does this apply to projectors?

Every projector has a 'native' resolution (sometimes called 'true resolution'). That's the maximum number of pixels it can actually project individually. So an SVGA projector can only display 480,000 pixels at a time.

There is a popular myth espoused by many projector salespeople that since an NTSC or DVD video signal is 480 lines, then an SVGA-resolution (600 lines) projector is plenty adequate to resolve all of the information in the video signal. "No point in buying an XGA machine," they say, "it's overkill."

Those who promote this myth are sorely mistaken. But it is a prevalent belief, so it's an issue that needs to be addressed.

 

The Difference between SVGA and XGA


As we said earlier most SVGA resolution LCD and DLP projectors have a physical matrix on their displays consisting of 800 pixels across and 600 down. That means there are 600 horizontal lines. XGA projectors have a physical display matrix of 1,024 pixels across and 768 down-768 horizontal lines. A quick calculation shows that XGA machines use 64% more pixels to display an image than do SVGA machines.

Anyone who gives it two seconds of thought will say,

 

"Hay, if the video signal has only 480 lines, then SVGA resolution has more than enough lines to display the video information. So stepping up to XGA is a waste of money—you can't squeeze any more info out of the signal."

 

Wrong! There are four issues that bear upon image quality that need to be taken into account: scaling, screen size/viewing distance, pixel visibility, and colour definition.

1. Scaling

If a projector displayed a 480-line video image in 480 lines, there would be no scaling. You would see a relatively pristine picture because you are viewing it without any unnatural scaling alterations attempting to stretch 480 lines of information into a 600-line or 768-line display.

By scaling a 480-line image up to 600 lines, the picture gets fuzzed somewhat since 480 lines of information cannot be stretched to fit across 600 lines as cleanly as it looks when displayed line-for-line. If the projector has a bad internal scalar, the picture will look terrible. But on most of the newest projectors the scalars are much better than they used to be. The net result is that the image on a good SVGA machine is reasonably clean but softer than it would be if displayed without scaling.

On an XGA machine, the 480 lines are scaled into 768. With the increased lines of resolution and 64% increase in pixel density, the scaling errors are smaller. There are more pixels available to approximate the original unscaled image. So the image is fuzzed less than it is on an SVGA machine. The result is that, side-by-side, an XGA resolution machine will generally deliver a sharper picture than will the SVGA.

Now please note, this comparison only holds for like technologies. For example an SVGA LCD unit will be less sharp than an XGA LCD. Or similarly, an SVGA DLP machine will be softer than its XGA DLP counterpart. Since LCD by its nature tends to be sharper than DLP for any given resolution, mixing technology types will confuse a comparison.

So. The bottom line is that XGA is capable of producing a sharper image than is SVGA, but not because it magically gets more out of the 480-line video signal. It doesn't. Rather, it is because the higher resolution XGA scaling softens the image less than does SVGA
.

 

2. Screen Size and Viewing  Distance

Your screen size and how far you sit from it is intimately related to image quality in this discussion. Assume you have an 8-foot wide screen and you set up two projectors side by side. Arrange them so they both have 4-foot wide images side by side on the screen and feed them both the same signal with S-video from a DVD player.

Now step back to view your demo from about 10 feet. Guess what? You won't see any difference in sharpness between them. The differences between them at that image size, and viewed from that distance, are too small for your eye to resolve.

Now move these two projectors back so each of them fills the 8-foot screen. Then alternate the projected images by covering one lens then the other. From the same distance of ten feet you will see that the picture from the XGA unit is quite obviously sharper.

So. Part of the "image quality" question surrounding SVGA vs. XGA has to do with your screen size relative to your viewing distance. If you intend to watch movies at a distance of 1.5 times the screen width, you will definitely see a big improvement with XGA over SVGA. If you view at a distance of 2.0 times screen width, the XGA will still have an advantage in sharpness. If you view at a distance of 2.5 times the screen width you won't notice any difference at all worth paying for.


3. Pixel Visibility

In video the visibility of pixels can interfere with your enjoyment of the image. In all cases XGA with its 64% pixel density advantage will have less visible pixels than the SVGA counterpart. A 100" image on a VGA projector has 64 pixels per inch, SVGA has 100 and XGA gives 164 pixels/inch. This difference greatly reduces the screen door effect on LCD projectors.

Once again, screen size and viewing distance are relevant factors. Let's replay the demo we just discussed. At a distance of 10 feet, you won't see any pixel structure On both the pixel structure is too small for your eye to resolve. But when each projector is blown up to the full 8-foot width of the screen, you will find that the SVGA unit has much more visible pixilation than does the XGA.

 

Example: on a modest projection screen of 2 metres width, from an SVGA projector each pixel is going to be a quarter of a centimetre wide, whereas with an XGA projector the image is going to be under a fifth of a centimetre wide, and over 60% more pixels are displayed. This means the image is going to be sharper and less 'blocky' when projecting with an XGA projector.

4. Colour definition

For any given image size XGA machines give you 64% more pixels. That means there is more capability to define shadings and nuances of colour. For any given image size if you focus on colour quality alone in a side by side demo, you will see colour tends to look a bit more refined or elegant on an XGA unit than it does on SVGA.

 

 

Conclusion


XGA resolution projectors are usually capable of delivering sharper images with less pixilation and better colour for any given screen size than their SVGA counterparts. The notion that since video has only 480 lines, you only need SVGA to display everything in the signal is a simplistic and erroneous way of thinking about the issue.

SVGA offer a cost advantage over XGA so if price is a major issue consider a used projector with XGA resolution rather than a new SVGA the difference is huge!

 

Resolution and Computers

 

You should also consider the longer-term investment you are making in a projector. Most computers sold today run in XGA resolution as standard, and SVGA is used less commonly. If you start using computers that run using XGA as standard in the future, you may find you are limited with an SVGA projector.

 

Can't I just change my resolution setting and buy an SVGA projector?

 

Yes you can, but the payoff is that you will lose sharpness and will have the inconvenience of having to make sure your computer is always in SVGA mode for presentations.

 

What is compression?

 

Most projectors will accept a resolution higher than their native resolution, but will compress the computer's image into fewer pixels. The result is that some of the computer's pixels are shared across the same pixel that the projector displays. This is less important with photos and video, because you don't notice it so much, but with text it's a different story ? especially small text, as illustrated by the picture below.

 

Native (True) Resolution
Computer and projector matched.
(Simulated Image, Enlarged 300%)

 

Non-Native Resolution
Computer is at a higher resolution
than the projector (compression).
(Simulated Image, Enlarged 300%)

 

The projector will automatically convert the incoming 1,024 x 768 signal to its native 800 x 600 output. However, there is always a loss of sharpness and detail in the process, so you will end up with a picture that is not quite as sharp as if the incoming signal had been the same format as the projector's native resolution.

This loss of sharpness also happens if you plug an SVGA computer into a higher-resolution XGA projector. You will usually get a decent image, but the conversion from the 800 x 600 input to a 1,024 x 768 output will produce some fuzziness that you may not appreciate after having spent the money for an XGA projector

Projectisle.com.au – “The Brands you know, Priced to go

 

______________________________________________________________

HomeAbout UsContactLinksPayment OptionsPrivacy PolicyProjector Guide

Site MapTerms & Conditions of SaleWarranty
 

 

Projector and projector Lamp prices are in Australian dollars and include GST, unless otherwise stated.
Prices and product availability can fluctuate and are subject to change without notice.

 

Copyright © projectisle.com.au 2014
All third party trademarks are hereby acknowledged

 

projectisle.com.au Is Proudly Australian Australian Flag : ABN: 53 135 231 917