Nowadays you can’t swing a cat without hitting an advertisement for a high-definition television, a computer monitor, or even a digital still camera or video camera without coming across marketing jargon talking about the resolution of the device. However, there’s a lot of fast-and-loose information out there concerning video resolution – here’s what you need to know about what it is and how it works.


What all those Numbers Mean


First, a little history: when the cathode ray tube television was invented, it worked by shooting electrons at a screen one line at a time. The electrons moved left to right in a single line and then dropped down to “paint” the line below it. The number of picture elements, or “pixels,” these CRT televisions could display, were represented by the number of elements on a line multiplied by the number of lines on the screen.

We still use this today, so when you see a resolution listed at 1920x1080, that means a monitor is capable of displaying 1,920 pixels per line over 1,080 lines – or a camera is capable of capturing images with the same amount of information. The higher those numbers, the higher the number of pixels each image is going to have – and that usually means clearer and crisper details. If you’re old enough to remember the change-over from older “standard definition” tube televisions to HDTVs, you’ll know exactly how big a difference a higher resolution can make.


Monitors versus Cameras


There are a few ways to measure resolution when it comes to consumer electronics. One is to list the actual pixel resolution either in full (like 1920x1080), which is common when it comes to listing the resolution of a computer monitor or the display on a tablet or a smartphone. When it comes to high-definition TVs (which are essentially large-sized computer monitors), these numbers are usually abbreviated to just the number of horizontal lines; 1920x1080 turns into a HDTV with “1080 HD” listed on its box at the store. One of the newest emerging standards for HDTVs, currently being marketed as “4K,” actually reverses this; 4K HDTV has a resolution of 4096x2160 instead.

However, still cameras and digital video cameras don’t feature the same conventions when their capabilities are advertised, even though they still work the same way. Instead of seeing a resolution listing you’re likely to see the approximate number of pixels altogether, usually listed in millions of pixels (or “megapixels”). In the above case, a camera capable of capturing images at 2160x1440 would have around 3 million pixels in each one – or around 3 megapixels. Nowadays it’s not uncommon to see digital cameras – especially those used by professional photographers – to have 24 megapixels or even higher. While this provides clarity and sharpness to recorded images, it also leads to very high storage requirements; it takes more space to store 24 million pixels than it does to just store 3 million of them, after all.