240 Hz? 600 Hz? What the heck? I thought I was trying to buy a TV!

This post is a bit technical, but keep reading. The ending will not disappoint. :-)

As a lot of people are looking into a new TV these days, I thought it might be interesting to talk about the signs you see in the electronics stores and on electronics websites. More specifically, what the heck is a Hz and why should I care? A Hz is measurement abreviation used on both current plasma and LCD displays. On a plasma, it refers to how many sub fields of pixel lines make up the screen. Each of those fields blinks 60 time in one second so thus a 600 Hz plasma has 10 sets of lines that blink 60 times in one second. LCDs are a bit different because they don't blink. An LCD has continuous light from the screen and the picture changes by the liquid crystal pixel hardening or softening when an electric current is run through it. Liquid crystal sometimes is slow to turn off and on and therefore can create an issue of motion blur on fat moving complex objects such as water or a high speed chase.

So what is 240 Hz then? On a plasma it refers to sub-fields of lines, but on an LCD it refers to frames per second (fps). So wait a minute, how does changing the frame rate affect the motion blur created by slow pixels? Well, it doesn't. A standard LCD runs at 60 Hz, or 60 fps. A 120 Hz tv runs at 120 fps and 240Hz runs at 240 fps and so on. The circuitry in the TV "predicts" what the frames in between the original 60 would look like and inserts a frame there. A 240 Hz inserts 2 frames in that space and so on. All of this to trick the eye into thinking its not seeing slow pixels.

So how many frames per second can the human eye see? Some say around 100, some say way more and other say way less. From what I can gather, the human eye sees light as a continuous wave pattern that does not change with distinct frames or flashes. Therefore, a true measurement is hard to get.

So here you are in an electronics store with all these Hz measurements and salespeople eager to earn a commission. Which TV do you think they want to sell you? You might be surprised. Salespeople are little more that a walking, talking advertisement for the products they sell. They are there to facilitate the purchasing process by advocating the product that suits your needs best. Here's the thing. Some salespeople are very knowledgeable and really want you to be happy with your purchase in order to avoid returns and a loss of their commission (bet you didn't know it get taken back). Others want to sell a product that will just make them a lot of money and take the risk that you may change your mind because the product you purchased was not for you and you probably knew that at the store except for that pesky sales guy who kept showing you the top of the line 65" TV that you knew wouldn't fit your room.... whew!!

What it all comes down to is this; look at the TV and stop looking at all the features!!! You may want to concider them as part of your overall purchase, but really just look at the picture. Do you like the colors, the blacks, the whites? Is it too bright for your room or maybe too dark? WIll it look elegent when turned off or will it be an eyesore? Can everyone who needs to use it understand how and can they all see it from all angles in the room? There are many things to consider so do yourself a favor and stop worrying about Hz.

By the way, movies at the theater are projected at only 24Hz. When's the last time you went away from seeing a movie in the theater and said, "I wonder how many Hz they were running that movie at? I bet it would look better with 120." I'm just saying...