The ANSI checkerboard seems simple enough, so why is contrast ratio so complicated?
(Credit: Ovation Multimedia)Contrast ratio should be black and white. Taken at face value, it's the ratio of the light level (luminance) the display produces when fed a white signal to the luminance when it's fed a black signal. Unfortunately, it's probably the most misused, inflated, and ultimately misleading specification used to describe HDTVs today.
At the 2009 Consumer Electronics Show, manufacturers quoted contrast ratio specs of 1,000,000:1 or 2,000,000:1 for upcoming LED-based LCD displays (Vizio and LG, respectively), which are similar to the specs quoted by Samsung and Sony for their current LED models. Those numbers sure do sound impressive, but what do they mean in the real world?
Very little. It's true that in general, a higher contrast ratio can indicate that the display produces a deeper level of black, with all of the picture-quality benefits that brings--but then again it might not. Despite the million-to-one contrast ratios of the Samsung and Sony LED sets we reviewed, we observed better black-level performance in the Pioneer PRO-111FD. Pioneer doesn't publish a contrast ratio spec for that television, but has claimed that its black levels are so deep as to be "immeasurable."
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We test monitor contrast ratio in a secret, undisclosed location.
(Credit: Eric Franklin/CNET Networks)Vendors want to sell you stuff! There, it's finally been said. Don't believe me? Well, you wouldn't be the first, but thankfully, I have evidence.
Within the last year I've seen a new spec, called dynamic contrast ratio (DCR), tossed around for computer displays. If you didn't know before, contrast ratio is simply the difference between the darkest blacks and the brightest whites a given display can produce.
Typically, computer displays have a contrast ratio of about 1000:1. However with DCR, you'll see numbers like 4000:1, 10,000:1, and higher. Basically, it's just a way for Company A to proclaim, "Don't buy Company B's monitor because it has a much lower DCR than our monitor." Since more and more vendors have been pushing this, I want to delve further into how they're getting these numbers. I also covered this topic in less detail (but with a sexy voice thrown in) in episode 2 of the Inside CNET Labs podcast.
Before a monitor is released to the public it goes through a bunch of testing in the vendor's own lab. These tests produce the specs that the vendor will then publish with the release. Specs like maximum brightness, pixel pitch, pixel response time, contrast ratio, and dynamic contrast ratio are all determined in the vendor's own lab.
When testing normal contrast ratio, vendors use a device that measures light to determine how much light is emanating from a display while it's showing both a completely black and a completely white screen. They then take each number, do a bit of math, and come up with the contrast ratio.
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In a time when CNET's two top-rated HDTVs of the year are Panasonic's TH-50PZ800U and Pioneer's PDP-5020FD, we have to wonder why a salesperson would recommend flat-panel LCD HDTVs at the rate that J.D. Power and Associates claims in a recent report.
Pioneer's Kuro PDP-5020FD, one of our top plasma HDTVs
(Credit: CNET Networks)The report, which surveyed more than 2,000 shoppers on their experience in big-box electronic retailers, a specialty television retailer, a mass merchant, and a warehouse store, found that retail salespeople recommended LCDs over plasmas at a three-to-one rate.
Sure, plasmas have a long list of supposed failings: they're allegedly bulky and power hungry, and have image burn-in issues and leaks, and a short lifespan. However, most of these problems--image burn-in being the most common with early plasma sets--have been resolved on modern plasma displays.
According to the report, however, "37 percent of salespersons warned their customers that images may be permanently burned onto the screen of plasma TVs." The lifespan argument doesn't hold up either, as both LCD and plasma lifespan claims are basically the same now at 60,000 hours each. And, with LCDs still costing more at equivalent screen sizes, it's certainly convenient for retailers to promote the LCD technology over its less expensive rival.... Read more
Birds, flowers, and geometric shapes. Oh, my!
(Credit: Viewsonic)Twnety-six-inch displays are not the most common size of monitor out there, but Viewsonic is doing their part in changing that. Today they announced the Viewsonic VA2626mw for a price of $530. This price makes it cheaper than Dell's 24-inch model, but still more expensive than some of the others we've reviewed. I mean you are getting two extra inches here, though...
You're also getting a DVI, VGA, and HDMI input for your video connection needs and two built-in 2.5-watt stereo speakers.
Viewsonic claims a native resolution of 1920x1200 and a dynamic contrast ratio of 6,000:1, which is a very high number. However there are reasons why you should not put too much stock into it. If I can get one in for testing, however, we'll see how close our contrast ratio test can come to that.
The display releases in July for $530.
(Credit:
Crave UK)
Most monitors are pretty much the same. There's a small percentage that are dreadful, a small percentage that are spectacular, and a small percentage you can punch really hard. But most are just OK, really. One monitor that's a good bet for the spectacular category is the LG Flatron L226WTQ--the world's first LCD computer monitor with a claimed 5,000:1 contrast ratio.
A high contrast ratio, for those not in the know, keeps images from looking washed out. You get very dark blacks, very bright whites, and ultimately a better picture. It's not that useful when you're editing images, doing desktop publishing or other dull office tasks, but it's jolly good for watching movies.
We've been playing with an L226WTQ for the last few days and, while we can't verify the exact contrast ratio (few people can), it's packing some seriously black blacks. And don't even get us started on those whites. The color reproduction seems pretty good too, plus you get 2ms gray-to-gray response time, HDCP over DVI-I for high-definition content, and a one-touch zoom function that lets you switch to lower resolutions if your eyes can't cope with 1,680x1,050 pixels.
The L226WTQ is available in black or a rather unattractive shade of gray for around 185 pounds (about $381). It'll be in U.K. stores in plenty of time for Christmas. Excuse us while we slip into our white lab coats--we'll bring you a review shortly.
(Source: Crave UK)
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