Stop lying to me about what I 'need'.

More by David Field

Latest Opinions

By David Field
16:34 Oct 2, 2008 | 13 Comments

Consumer digital displays (oh alright, LCD TVs and some LCD computer monitors) are getting steadily better across the board. But in an attempt to lure customers, the companies that make them have resorted to adding crap to their displays that reduces the overall picture quality.

I'm talking about the new evil in displays -- dynamic contrast ratio.

Contrast ratio is the ratio of the blackest black a screen can produce compared to its brightest white; and it's also the most useless measurement in video. Results can vary wildly. Measurements in an all black room can be double the measurements in the same room with a white ceiling, because the light from the display can bounce and reflect off the screen, which raises the brightness of the black areas of the image.

Dynamic contrast ratio, however, is like Cold Power: it claims to make your whites whiter and your blacks blacker. It's a way of trying to fake depth and richness, but because the screens it's built into are actually quite deep and rich without the feature, it's not only unnecessary but it manages to mangle your video in the process.

And more importantly, it's easy to mislead people with the inaccurate measurements taken when dynamic contrast ratio systems are running.

Dynamic contrast ratio systems work by detecting the median brightness of the image. If a scene exceeds or drops below set brightness or darkness thresholds, the contrast ratio is increased or the backlight that illuminates the image is dimmed to make the scene appear brighter or darker respectively.

It generally takes about half a second for this system to detect and change the display’s settings. So what happens if a dark scene strobes white for a moment, and then returns to dark? The display suddenly turns up both the brightness and contrast, and then turns them both down again. This can happen over the course of a second. Yet for the vast majority of that time, your image has been displaying the dark scene.

Directors, broadcast engineers and image technicians have many complex systems to ensure that images are repeatedly and accurately displayed on monitors, cameras, colour correction facilities and cinemas. But they can’t account for the millions of differently calibrated TVs in homes all over the world, so they get the signal as close to what can be considered 'normal' for as many sets as they can, then send it out to you.

But now your TV is messing with the brightness and contrast dials like a rhesus monkey conditioned to getting a nicotine hit after twisting the dials.

Unpredictably changing the setup of a display on the fly destroys the underlying emotional response evoked from the visual stimulus that directors and image professionals work so hard to evoke with their calibrated gear. That bright light in the distance of a dark scene isn’t as bright any more, and those slow, fluid cross-fades from bright to dark scenes are suddenly jerky and uneven as they are butchered by the dynamic contrast setting.

And all for what? A bigger, useless, arbitrary number to tackily scrawl on a piece of cardboard that gets stuck on the side of the display in a store.

This is just the latest instance of technical marketing taking advantage of people’s cluelessness. It’s in the same league as the megapixel race in the world of handheld cameras -- where a higher number doesn't mean a better image. You can prove this by printing two images; one from a 6 megapixel camera-phone, and one from a 6 megapixel Canon 300D.

Your image resolution (measured in megapixels, or millions of pixels) is proportional to the number of photosites on the sensor of your camera. Photosites detect and react to light, then record the information as a value for the pixels that make up an image. They usually get less than a 25th of a second to bathe in light and record a value. To get more megapixels on a sensor, you need to add more photosites. Because the area of the sensor is fixed, the photosites have to be shrunk before more can be added. The smaller the photosites are, the less light they get to bathe in, the lower the values they return and the more you have to turn up the gain up on the output to get a usable image. Which leads to a noisy and rubbish photo.

If your engineers don’t have the resources to design more sensitive photosites to compensate for this, but you still need to increase the resolution of your sensor, you can resort to interpolation. This can add as much resolution as you want the sensor to pick up, but goes all diminishing returns on you as you try and squeeze more detail out of it. The theory is simple: guess what the values of your hypothetical pixels would be and add those approximations to your image to increase t3h m3gapix3lz!!1!LOL!.

Why increase the pixel count if it's not going to give you higher quality images? Because if you stand at the camera counter at any electronics store and listen to what people with credit cards at the ready are asking, the most common question people want answered is "How many megapixels has it got?".

Sadly, even though numbers aren't everything, the ‘more is better’ yardstick is the only easily comprehensible way for consumers to try and quantify quality. People are scared of knowing anything more detailed than that.

It’s why you see VGA webcams (which have 640 x 480, or 0.3 megapixel sensors) ‘delivering’ 8 megapixel images. It’s why there are phones with 10 megapixel cameras onboard.

It’s why dynamic contrast ratio exists.

And it cheapens the effort that goes into making technology that makes images legitimately better.

And it makes me angry.

Ads by Google

13 Comments

Felipe Oct 2, 2008 6:14 PM	Amen. FX.
SceptreCore Oct 2, 2008 6:17 PM	Yes but out of all this DCR makes the "Consumer digital displays" use less energy then static contrast ratio. And it does affect the viewing pleasure of movies
smadge1 Oct 2, 2008 6:46 PM	what's with the engadget hate?
GhostFaceKilla Oct 2, 2008 8:02 PM	Im angry too. oooo my blood is boiling. /goes back to watching SONY TRINITRON CRT TV.
Dr Doom Oct 3, 2008 8:14 AM	Agreed +1
SyKRyD Oct 3, 2008 10:17 AM	this is an example of what separates the geeks and everyone else. how many of you try to work out how something works? try to understand the things that you buy, you use, you work with tick? how many of you have partners, friends and family that don't have or don't want to have this knowledge. no matter how much you try to explain something, they are happy with to live out their ignorant lives. that is, until their computer breaks down and they need someone to fix it. or they've just realised that the new expensive plasma they just bought, doesnt have a hdmi out for their pvr. i swear, geeks will one day rule the world when all the ignorant and clueless all die off from darwin's theory.
R430R Oct 4, 2008 11:13 AM	I think it's a little ironic....please, call me crazy....but when I got to the bottom of this article I noticed that there were two advertisements one for LCD TV's and one for a CAMERA :S. And sceptrecore ya gotta remember we're geeks.......we make computers that blow fuses...we need fire extinguishers next to our computers when we enter our BIOS as a "JUST IN CASE" scenario...Dude we don't care about power hey LOL Remember an orange is an orange and technology is technology.....to conquer with both without making a mess ya gotta be smart :)
SceptreCore Oct 5, 2008 2:30 PM	You may not R430R, but the more discerning members of the public that pay bills do. I checked out my monitors power usage before purchase, and it's quite a good one. I know that DCR is all just about the range the backlight can dim.... but if it keeps the picture looking just that bit better then the others with a lesser range... does it really matter. David there isn't anything to be mad about, this is what happens to technology when engineers don't know what the next phase is.... they just improve whats there (and charge a premium for it) Once they know what will next revolutionize how our pixels are displayed.... then the train will role again.
colganaitor Oct 7, 2008 1:49 AM	Wow. I'll remember this when I need a camera.
wheelz Oct 9, 2008 12:29 AM	I actually DE-PC'D and looked at all the screens in action before I decided to buy. I went with my own DVD and if the Shop wouldn't oblige, I moved on. I bought the one that looked the best with my control DVD. I didn't even look at stats, other than to make sure it was full HD. Because I spent a pretty penny, and I originally liked the picture quality, NO_ONE can stop my wood while watching it. I love it. In a disturbing way :) It has DCR. Sigh.
^Faldo^ Oct 13, 2008 10:51 PM	@wheelz: Then turn it off! -DAVE.
AnthraxPants Oct 23, 2008 3:43 PM	Research, research, research! You can save a lot of dough if you understand a little about what you purchase. I saved between $100 to $150 on most of the major components in my last upgrade, allowing me to buy better gear and get very good 'bang for buck'. Articles like this one are very helpful when considering what to buy. wheelz - If your screen does not have an option to turn off dynamic contrast ratio you may be able to disable it by changing to movie or cinema mode.
A23 Oct 10, 2010 6:11 AM	In the mid 90's someone at Imperial in London who was working on image sensors told someone pretty much the same as David Field about the expected marketing BS of 2005 onwards once cameras and displays had cracked "Two MegaPixels" with a contrast ratio of "2000:1" because those would exceed what could be seen on good "high resolution" digital TV flatscreens. And then they suggested a glossy clear perspex TV border, either black or white behind shiney clear to distract from the imperfect anti-reflective coating on the flatscreen. Who wants to know whats' next?

Comments have been disabled on this article.

Latest Competitions

Thermaltake kicks off your gaming year with a BANG
Thermaltake has started off the new year with a bang by giving away a Tt eSport Theron Laser mouse to not one or two, but TWENTY lucky Atomicans!

Atomic Magazine

Issue: 133 | February, 2012

Atomic is a magazine aimed squarely at computer enthusiasts, gamers, and serious PC upgraders.

Every month we bring you the latest reviews of new technology and PC components, in depth features on everything from overclocking to console hacking, and gaming previews and interviews.

What's in this issue?