Have you ever wondered about the difference in the images in the film you just saw in the theater and the sit-com you are watching at home on television? They have a different “aspect ratio,” which is the difference in the way screens are displayed. Aspect ratio decides the dimensions of the images you see, and is different depending on the format in which you are viewing the video.
The two predominant aspect ratios in use today are 4:3 and 16:9. The 4:3 ratio is the most traditional aspect ratio and was the first format beginning with the earliest silent films. Today it is the format used by traditional television and is marked by a more “square” feel. 16:9 is a “widescreen” or “letterbox” proportion that leaves the width much larger than the height. This is what all movies are now shot on, and what television programs will be displayed on when High Definition broadcasting becomes standard. 16:9 is now often noted to have a much more “cinematic feel” than 4:3.
When you are recording it is important to decide what aspect ratio you would like the project to be in. 16:9 is much closer to the actual aspect ratio that people see in, and it is easier to use visual vectors and the “rule of thirds” in the frame with this aspect. 4:3 is often easier to use outside material in editing, such as photographs or flyers, which may be in a more square shape. No matter what you choose you need to make sure you are consistent and do not change the aspect ratio you are recording in halfway through the project. If you do accidentally record something in 4:3 when the rest of your project is in 16:9, or vice versa, you can usually alter this in your editing software. To do this you have set up the Viewer so that the sequence is in the preferred aspect ratio. Then you would either make the image large enough so that it cuts off parts of the top or sides and reformats, or use a cropping tool to make it fit the aspect correct ratio. Likewise, you need to always set the appropriate aspect ratio in your editing software before capturing footage, otherwise you will end up with footage that is either stretched or squished.
At the end of the day it is often a safer bet to choose 16:9 because it generally looks more professional and is becoming the new standard. This is your project and you must pick all the visual elements that you feel fit your vision the best.