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Digital Photography Basics – What is Aliasing?

If there’s one thing that digital photography has no shortage of, it’s confusing vocabulary words. Aliasing, which is a common word in the world of digital everything (video games, CGI, photography), is one of those words that everyone has heard, but may not quite understand. And when it comes to digital photography, anti-aliasing is a common feature found on many digital cameras but is rarely explained. Don’t worry though because here we’ll explain it and it isn’t nearly as complicated as it sounds.

The Basics About Pixels

Most digital images are made up of square units known as pixels. If you take any of your digital photographs and zoom in a few times, you will notice that the closer you get, the more blocky the image appears. This blocky appearance is the result of the individual pixels becoming more pronounced as the digital image is increased in size.

Your camera’s resolution is directly related to the number of individual pixels it can capture in a given frame as is often referred to as the mega pixel value. The higher the resolution, the more pixels you get. The more pixels you have, the smoother the lines in your image. For example, think of a staircase where it looks blocky up close but as you move further away it looks more like a diagonal line. This is how pixels create shapes in an image.

The Basics About Aliasing

Aliasing refers to the edges of round or diagonal lines in your images, which are all made up of square pixels. When you see this pixels drawn rigidly and in only one color, the lines will look more noticeable and jagged. This may not be immediately visible if the pixel is surrounded by others of a similar color, but as the colors increase in contrast, the pixel will increase in visibility.

Aliasing is not usually obvious unless an image has been taken at a very low resolution. Most modern digital cameras shoot at resolutions that make aliasing nearly unnoticeable to the naked eye, however it is easy to spot once these images have been blown up from their original size. All digital photographs have some level of aliasing, no matter how good the camera may be.

Anti-Aliasing Explained

Anti-aliasing allows the colors at the edge of pixels to bleed into one another, creating a sort of blurred effect. It may sound counterintuitive, but blurring the edges of each individual pixel will result in sharper images with smoother lines and more natural color differentiation.

To test this out, take one of your digital images and reduce it in size. You will no doubt notice that as the size decreases, the lines of objects in the photograph will seem smoother. When the pixels in the picture get smaller, they become less noticeable. This is a similar effect to anti-aliasing – slightly blurring each pixel makes it stand out less and blend more smoothly into the image.

Most digital cameras come fully equipped with a built in anti-aliasing feature. Not only will anti-aliasing make your pictures look more natural, but it will also help to offset any loss of image quality caused by a lower resolution camera. Although it is always good idea to shoot at the highest resolution possible, anti-aliasing will help to make sure your images look great.

Although you may not have realized how important anti-aliasing was before, once you understand the impact on your pictures you won’t want to shoot without it. Anti-aliasing really helps to bridge the gap between expensive super high resolution cameras and the price of the average digital camera by eliminating the rough, jagged lines of aliasing. If your camera has an anti-aliasing function, make sure to always have it on and your pictures will certainly thank you.

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