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TCL 40FS3800
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Best smart TV

TCL 40FS3800

Demystifying HDTV TV features and specifications

It's no secret that TV sales are in the dumps. Part of that is the economy and part is that thanks to the transition to a digital TV standard, most families have purchased a new TV in the not too distant past. To get those TV owners to upgrade their sets again, manufacturers are cramming more and more technological wizardry into their products, including Internet connectivity to access additional content. Most flagship sets -- and now many mid-grade and even some budget sets -- boast higher-than-high definition 4K resolutions, and some now feature curved screens. Some makers continue to offer 3D as well. Of course, all of this adds to the bottom line of a TV set, but how much of it adds to the viewing experience?

Smart TV

Internet-capable TVs are now mainstream, and many reviewers appreciate being able to stream movies and other entertainment from services such as Netflix, Amazon Instant, Hulu Plus, Vudu, Pandora and many more. Some companies offer some type of mobile-phone-like app store, while others have turned to third party platforms, including Android and Roku, for content. Many Smart TVs also include at least rudimentary web browsing capabilities, Skype compatibility (sometimes including a built-in webcam), and other bells and whistles.

Entering text, scrolling through menus, and making on-screen selections can be a real pain with a standard remote control, so many higher-end sets come with augmented remotes with full QWERTY keyboards and/or some type of pointing technology to make navigation easier. The most advanced sets also incorporate some type of voice or gesture controls, but the success -- and usefulness -- of those varies. Built-in Wi-Fi is commonplace in all but the very cheapest streaming-enabled sets, so you don't have to worry about having a nearby wired network connection to access all of the online goodies.


Despite TV manufacturers' best efforts, 3D hasn't been a rousing success. Some makers continue to offer 3D, but many have reduced the number of sets with that feature and have taken other cost cutting measures, such as making the glasses an optional accessory (though the price of glasses has fallen from their original $150 per pair to a more palatable $15 and up). Glasses-free 3D TV remains under development, but for now is still something largely reserved for technology demonstrations and trade show floors. No current commercial set includes glasses-free TV, and earlier efforts were very disappointing, and very expensive. Still, experts say that glasses-free 3D technology is a must if 3D is ever to enjoy wide adoption, but when -- or if -- we will ever see a viable consumer set that includes it remains an open question.

Enhanced refresh rate

When shopping for a TV, you've probably noticed that manufacturers often tout models with higher refresh rates such as 120 Hz and 240 Hz. This refers to how often a TV image is repainted on the screen. Up until a few years ago, all TVs used a refresh rate of 60 Hz, which means the image is repainted on the screen 60 times per second. That's fast enough so the eye sees one fluid, moving image rather than a string of individual frames.

Boosting the refresh rate to 120 Hz or 240 Hz updates the image two or four times more often. What's the advantage? LCD TVs have traditionally been criticized for being prone to motion blur, which is caused by LCD's relatively slow natural response time. A faster refresh rate in these sets forces the screen to update more often and overrides the slower response times, wiping out motion blur in the process -- or, at least, that's the theory.

Whether a faster refresh rate makes a noticeable difference in reducing motion blur is a matter of some debate. It does appear to sharpen test patterns and certain types of motion in LCD TVs, such as fast-moving text on a crawler. Lots of experts say they see the most improvement moving from 60 Hz to 120 Hz, with the jump to 240 Hz yielding only a little further sharpening.

The issue with enhanced refresh rates became more complicated in recent years when many TV manufacturers began marketing sets with inflated specifications, backed by a little technical sleight of hand. spilled the beans on this back in 2012, and recently reported that the practice continues unabated. Some reviewers, such as CNET, report a TV's true refresh rate in addition to the manufacturer's claimed specification.

Enhanced refresh rates are sometimes confused with dejudder technology, which is no surprise since the two are often interlocked. Dejudder refers to eliminating a subtle shaking artifact -- called judder -- in content originally recorded on film. While some find judder objectionable, it's what gives film-based video its distinctive "movie" look. Remove judder, and the content looks like it was shot directly to video. Some love the look of the smoother motion but others hate it, calling it a "soap-opera effect," or something a bit less polite. TV manufacturers market dejudder technology under various names, such as Sony's MotionFlow or Samsung's Motion Plus.

Edge lit or full matrix?

Before 2012, the question LCD TV buyers had to answer was whether they wanted an LED backlight or a standard CCFL (cold-cathode fluorescent lamp) backlight. The use of CCFL technology has now all but disappeared, so the question has become whether buyers want an edge-lit LED design, with LEDs located only at the edges of the screen, or a full-matrix array, often called direct-lit since each pixel subgroup is lit by its own LED. Each type has its pros and cons.

Sets with full-matrix backlights can be significantly more expensive than ones that are edge lit, but some budget TVs use direct-lit backlights that cut costs by using fewer LEDs. Direct-lit sets are slightly thicker than edge-lit sets and are more prone to an artifact called blooming, in which light appears to leak from bright objects surrounded by a dark background. On the plus side, they often have better uniformity (blacks and/or colors are the same from edge to edge on the screen) and better black levels. Blacks can be deepened still further using a technique called local dimming where groups of LEDs (called zones) are actually turned off in areas that call for pitch black. The more zones an LED TV backlight has, the better the effectiveness of local dimming.

An edge-lit LED backlight is thinner than a direct-lit one and more energy efficient, but these LED TVs struggle more with screen uniformity. Owners tend to complain of edges or corners that are brighter than other parts of the screen, especially in very dark scenes. The issue can vary from set to set, however, and bothers some viewers more than others. Some edge-lit sets use a version of local dimming as well, but effectiveness is more uneven -- helping black levels on some sets, but either having little effect or even harming picture quality on others. Buyers of OLED sets need not worry about the backlight, as that technology does not use one.


4K sets, also known as UHD or Ultra HD, have screens featuring resolutions that are roughly four times that of standard HD sets. When fed with native 4K content, these TVs are capable of incredible picture quality.

That's part of the rub with 4K. Up to now, there has been virtually no native 4K content available. Instead, 4K sets have mainly been up-converting standard HD images to fit their screen resolution. The result can be very nice, but 4K TVs can't reproduce information that's not there in the first place. That's why DVDs up-scaled to high-definition resolutions by a Blu-ray player or HDTV can look very good, but not quite as good as a Blu-ray Disc.

Things are slowly starting to change. Netflix streams some of its content in 4K, including original series such as House of Cards and popular programs such as Breaking Bad, as does Amazon Instant video, YouTube and a few other providers. According to this report, Blu-ray disc players able to play back new 4K discs are expected to debut in early 2016.

In the meantime, 4K resolution is now pretty much part of the package with most better-quality TV sets. It's also being found in many mid-range TVs, some budget sets priced at less than $1,000, and even in a handful of televisions that cost less than $500.

Curved or flat screens?

If you are in the market for a flagship TV, you've no doubt noted that some high-end models now sport a curved screen rather than the traditional flat one. Manufacturers are quick to tout the supposed advantages of this innovation, including a more immersive viewing experience, reduced image distortion, and reduced reflections.

Experts aren't as sure, and some say that while the aesthetics maybe something that's desirable, on balance, there's no appreciable difference in the overall viewing experience, at least not in a set with a 70-inch or smaller screen size. That said, in some situations, curved screens can provide some advantages. A curved screen can produce fewer reflections than a flat screen, though light placement still will need to be considered as any reflections the screen does produce can be magnified -- stretched over the entire face of the screen in extreme situations.

Curved screens also eliminate some of the unavoidable geometric distortions introduced by viewing on a flat screen, but introduce a few of its own related to viewing on a curved surface. Which set of distortions is more bothersome will vary by viewer, so if you are obsessive about such things -- and most viewers never notice them in the first place -- check out a curved screen before committing to one.


There's always some new wrinkle when it comes to TV technology, and for 2015 it's High Dynamic Range, or HDR. If you are not in the market right now for a flagship TV, you can skip right by this section, but the first HDR-capable 4K sets are now available, and more are on the way. Basically, HDR sets can deliver both higher contrast (the difference between the black level and the white level) and a wider color gamut (more colors) -- with the result being a more lifelike picture. However, it requires specially processed content to do so; has begun limited streaming of HDR video, but there are few other sources as of yet. For more on the details, has a good but not-too-technical article that describes the technology.

Quantum Dots

Having the ability to reproduce a wider color gamut is one thing, having a screen that can take advantage of that and accurately display those expanded colors is another. That's where Quantum Dots come in. These ultra-small bits of semiconductor allow for better, more accurate color rendition than possible using a standard LED backlit LCD TV. The technology is offered under a number of different marketing names by different manufacturers, including Triluminous by Sony and Nano Crystals by Samsung. If you want more information, this article at gives the details.