!#5: Refresh Rate Explained - 100Hz, 200Hz and 600Hz Compared

!±8± Refresh Rate Explained - 100Hz, 200Hz and 600Hz Compared

Refresh Rate Explained

Trying to choose a Tv today can be difficult. Very difficult. One of the most widely debated features of flat panel Tvs is the ever confusing Refresh Rate. There are quite a whole of separate refresh rates being featured on today's Digital Tvs. 50Hz, 100Hz, 200Hz, and 600Hz. These Refresh Rates can legitimately divide opinion.

What is Refresh Rate, and why is it important?

Every video we watch is made up of thousands of "frames". The refresh rate, or "Hertz" (Hz) is a quantum of the whole of frames shown on your Tv screen each second. Remember in your younger years, when you were bored in school and used to draw a stick frame in the top projection of every page in your book, and then flick through it quickly to make it look like it was moving? This is basically what your Tv is doing to yield request for retrial on the screen.

It is refreshing (i.e. Flicking) through frames (i.e. Pages) to yield motion. Now the quicker you can flick through pages in your book - the faster and smoother the stick figures request for retrial seems to be. Secondly, the more stages of movement you draw the stick frame in on each page - the more natural it will seem to move.

So let's go back to our Tv - if the same important is applied, then the Tv is able to show you a smoother request for retrial if it can flick through its frames quicker. And by adding extra frames in between other frames - this causes the Tv to yield a smoother transition from one frame to the other. So, the more times the screen can be "refreshed" every second, the smoother the image's request for retrial will seem to be.

The approved broadcast signal we receive in Australia is 50Hz. That means that the image on your Digital Tv is refreshed 50 times each second. 50Hz is a fairly slow rate, and it is potential to see blurring or judder in the photograph when watching fast arresting sporting events or operation movies, or any scenes where the camera pans over very fast. So the way the Tv fixes this issue is to generate intermediate frames and then insert them between the former frames. This is referred to as interpolation, or 100Hz Technology.

"100Hz technology doubles the whole of frames shown per second which helps to cut the blurring and is ideal for watching operation movies and sports."

To some people, the 100Hz request for retrial can seem to be a bit "too" flat initially, but once you adjust, it can be very difficult to return to a 50Hz Tv, especially on a large screen. Today, larger and larger Tvs have become very accessible in terms of price. Now because the photograph is bigger, you will notice things like judder even more.

The majority of these large Flat Screen Tvs (if not all) are 1080P Full Hd. That means that there is a lot of facts being displayed on the screen, and all of that facts needs to be moved nearby very fast for it to look smooth. On a large Flat Screen Tv running at 1080P and 50Hz, fast panning shots can show a lot of judder, because there is just so much image facts being shifted nearby the screen, our eyes will pick up a lot of request for retrial artefacts. So essentially, by doubling the whole of frames, 100Hz removes the majority of request for retrial judder.

So if 100Hz gets rid of judder, why do I need 200Hz?

Interpolation at 100Hz is good, but again, with a lot of Full Hd, high resolution article like Blu-Ray, Gaming and more recently 3D Technology, now ready to every home, and 46" - 65" Led screens surging in popularity due to plummeting prices - there's more benefit to be had from your Tv doubling its refresh efforts. While 100Hz will legitimately take off a lot of request for retrial judder from Led Tvs and Lcd Tvs, the bigger the screen, the more apparent the remaining artefacts and judder become. So 200Hz was born...

By inserting 3 added frames between each existing frame, instead of one as 100hZ does, 200Hz processors heighten request for retrial smoothness added and result in production objects look more "solid". The aim of 200Hz is to keep objects such as Soccer Balls, or any small objects arresting very fast over the screen, from losing their shape, blurring or breaking up when being propelled over the screen. However, it's not as simple as just adding an extra three frames - that's not quite the extent of the technology. A processor inside the Tv looks at two sequential frames and then legitimately creates three New added frames in between them.

Going back to our stick frame analogy, that means drawing four times as many stick figures by using four times as many pages, and flicking through those pages at the same speed. This fact, however, is where some 200Hz Tvs result - or fail miserably!

Imagine you've drawn a stick frame on fifty pages, and can flick through those fifty pages in one second, without missing a page, and at a constant speed. Now double those pages, and you will find it harder to flick through the whole hundred pages without missing a few - let alone the same speed throughout. So your stick frame may seem to move smoothly, then judder, then smoothly again. Now, imagine trying to do that with two hundred pages. It's a struggle, and you are sure to miss a whole of pages along the way. To put it one way - some people will do a great job than others.

This also rings very true for Tvs. There are some processors out there which do a much great job than others do. There are some 200Hz processors which don't quite cut the mustard, and you can see odd frames skipping, lots of inaccurate and seemingly unnatural movement. So beware - not all 200Hz processors are created equal!

A lot of Plasma screens seem to highlight 600Hz - they must be at least three times faster, right?

Well in short - not exactly! What 600Hz Sub-Field Driving does, with a 50Hz source like how our Australian Tv is broadcast, is split each frame into 12 cut off frames or "sub-fields", and then show them individually on the screen. What it does not do is generate New frames. That means 12 sub-fields per frame in 50Hz (frames per second) creates 600 frames per second (50x12=600). The more sub-fields you have per frame, the more literal, the colour fertilization and less photograph noise.

So technically, 600Hz sub-field drive is not solely associated to, nor is its former purpose, eliminating request for retrial judder.

Why are the manufacturers causing all this confusion?

Because Plasma vs. Lcd technology is still the biggest moot when it comes to selecting a Flat Screen Tv. The variation in technology is causing manufacturers like Panasonic, Samsung, Lg and Sony to heavily promote features and benefits of their panels to attract customers.

As far as Lcd, and now Led Digital Tv Panels have advanced - the fact of the matter is that for smooth, natural request for retrial in fast scenes - a Plasma is still superior.

With the way Plasma technology works, 100Hz or 200Hz isn't a beneficial highlight to have. But with Lcd and Led heavily marketing 100Hz/200Hz, from a marketing perspective they needed a whole to combat that. Some added 100Hz before, but now 200Hz Led and Lcd have become more common, so they've started quoting the sub-field whole - 600Hz.

The same thing happened with 1080p and 'Full Hd'. Lcd manufacturers introduced terms on their Tvs - purely from a marketing perspective - to try and deflect attentiveness from the fact that a good Plasma Tv produced a more "natural" picture.

In reality, the plasma manufacturers are being slightly misleading in how they store 600Hz sub field driving. In one way they are saying to customers that our 600Hz is a highlight that helps take off request for retrial judder three times as much as a 200Hz Tv.

While this is not directly true - they are using it to promote a very true highlight of plasma technology - classic request for retrial handling. There is a small bit of "the pot calling the kettle black" when it comes to the Lcd manufacturers though. While it is true that 200Hz was designed to aid request for retrial on a large screen Tv - the fact that the resulting image can often seem unnatural during fast scenes puts a big ask mark over whether this aids or hinders what the customer is seeing. The insertion of frames that are not meant to be there can make it all look a small fake, in many people's opinion. If you do encounter that, it's best to disable it for that single movie.

So, what is best? 100Hz, 200Hz or 600Hz?

In summary, for fast paced natural movement, Plasma screens are still superior. They do not need to generate extra frames to eliminate request for retrial judder, so the resulting image seen is not fake or unnatural. There are pros and cons for both Plasma and Lcd technology, and concept will all the time be divided one way or another, but if you prefer a smooth, natural photograph - even though Lcd and Led technology has improved immensely - a Plasma screen is still the way to go.