How much does resolution affect your final video? Learn the basics from SD to 4K, including how it’s measured and commonly used terminology.
One of the options you’ll need to consider when you’re about to shoot video is resolution. The resolution of your video refers to the number of pixels that make up a single frame of video. There are a wide range of options from Standard Definition to 4K. It’s important to note that ultimately, many of the benefits of higher resolutions are largely dependent on the screen size and viewing distance. The basic idea here is that the bigger a screen is, and the closer you get to it, the more likely you’ll see the benefits of a higher resolution. Conversely, the smaller the screen is, and the further you get from it, the less likely you’ll see the benefits of higher resolution. Keeping this in mind, let’s talk about what all those terms and numbers actually mean. Resolution uses two numbers to represent the number of pixels that make up an image. This is typically expressed as the number of pixels that make up one horizontal line by the number of pixels that make up one vertical line. A common example of this is 1920 x 1080. This means there are 1,920 pixels across one horizontal line of the image, and there are 1,080 pixels across one vertical line of the image. To determine how many total pixels make up the image, we can multiply the two numbers. In the case of 1920 x 1080 we can see that the image is made up of 2,073,600 pixels. This is sometimes abreviated into megapixels. In this case it would be around 2.1 megapixels. Just to make sure that things are a bit confusing, many people and manufacturers refer to resolution by using only the number of pixels in the vertical or horizontal line, and they sometimes even include a letter after the number. In the case of 1920x1080 you’ll hear it referred to as 1080p and 1080i. the p in 1080p stands for progressive, and this has to do with the way each video frame is recorded. the i in 1080i stands for interlaced, and also has to do with the way each video frame is recorded. Another component that’s related to the resolution you choose is the Aspect Ratio. The aspect ratio refers to the proportional relationship between the width and the height of the frame. In the case of 1920x1080 the aspect ratio is 16:9 or 1.77 to 1. This means that the final image is 1.77 times as wide as it is tall. This aspect ratio is the standard for HDTV, while 4:3 is the standard for SD video. Because nothing in video is ever simple, another factor to be aware of is pixel aspect ratio. Many video formats use square pixels, but some camera’s may employ pixels that are not square. Pixel aspect ratio describes this. For instance DVCPROHD uses a pixel aspect ratio of 1.33. this means that each pixel is 1.33 times as wide as it is tall. This is sometimes displayed as 1.33 PAR. This allows the format to employ a 1440x1080 resolution, while maintaining a 16:9 aspect ratio. Fewer pixels saves on space, but can cause image quality to be degraded. So, now that we know how to interpret the numbers, let’s talk about the most common resolutions you’re likely to encounter, and let’s start at the bottom. 480p or 480i is considered standard definition and typically falls around 720 x 480. This means 345,600 pixels make up your image. This was a very common resolution before High Definition became widespread. These days, there aren’t really any advantages to using this resolution, unless your camera simply can’t shoot at a higher resolution. DVD’s are produced in Standard Definition, but you can downscale higher resolution footage and get good results. Next up we have 720p. This can refer to a resolution 960x720 with a 1.33 pixel aspect ratio, or 1280x720 which uses a 1.0 square pixel aspect ratio. Both of these resolutions achieve the 16:9 HDTV standard, but are not considered to be FULL HD. A 1280x720 image is made up of 921,600 pixels, more than 2 and a half times the number of pixels of 720x480. 720p is a popular choice for cable and satellite providers, as well as streaming internet video, because the quality is good, but the bandwidth required is lower than our next resolution up the ladder. 1080p and 1080i are the standard for FULL HD video. This can refer to a resolution of 1440x1080 with a 1.33 pixel aspect ratio, or 1920x1080 which uses a square a 1.0 square pixel aspect ratio. Both of these resolutions result in a 16:9 image. At 2,073,600 pixels 1920x1080 is more than double the resolution of 1280x720. This is a popular resolution choice with widespread use across television and the internet. Moving further up the ladder, we arrive at 2.5k. Rather than referring to the number of vertical pixels in one line, 2.5k refers to the approximate number of pixels in one horizontal line 2.5k, at 2432x1366 has 3,332,112 pixels, more than 1.5 times the number in 1920x1080. This increased resolution can help the image look better if you’re planning on showing your project in a theater, or give you some ability to scale and reframe your shot if your ultimate destination is 1920x1080. Finally we arrive at 4K. While this has been a mainstay of high end digital cinema for awhile, this resolution is finally working it’s way into affordable cameras for video producers and budding cinematographers alike. 4K is a reference to the number of horizontal pixels in one line of an image. There are two primary resolutions that 4K refers to. UHD, or ultra high definition television refers to a 3840x2160 resolution. This keeps the aspect ratio of 16:9 intact, and gives a whopping 8,294,400 pixel image, which is 4 times the resolution of FULL HD or 1920x1080. There’s also DCI 4K which is 4096x2160, giving it a 17:9 aspect ratio for film projection. Okay, we know the tech specs, but how do we choose which resolution to shoot at? If we all had the right camera, an infinite amount of time and high end computers built for video, there wouldn’t be any reason not to shoot 4K whenever possible. More pixels means more detail in an image. And even if don’t care about 4K as a final output resolution, you can still reframing shots in post production for 1920x1080 output without losing of quality. Plus it will ensure that your footage will remain useable for the foreseeable future. While not everyone has a 4K computer monitor or TV, the pendulum is swinging away from HD and toward 4K. The main limitation to working with higher resolution footage is your computer hardware. Most professional level editing software supports 4K workflows, but you’ll need a powerful computer with a fast hard drive, high end gpu, tons of storage space to accommodate larger file sizes, and an expensive monitor if you want to view it at full resolution. Another factor to consider is if you really want to reveal the extra detail in a scene. Wardrobe, makeup, and set design that looks great in SD typically doesn’t stand up to HD resolution, and likewise, a scene that looks great in HD may need more work to look good in 4K. If your camera is capable of shooting 2.5K, and you’ve got the space and horsepower, it can be a happy medium between Full HD and 4K. . It will be feasible without using the top of the line computer hardware, and requires less storage space than 4K, while still increasing the details in your footage While 2.5k and 4K cameras are fantastic, many of us still have cameras that shoot 1080p, 720p, and 1080i. If your computer can support 1080p footage, and you’ve got a large enough memory card to shoot on, then there’s really no benefit to shooting at 720p or 1080i. Even if your final destination is 720p, you can downscale your footage, and even reframe your shots a bit, while keeping your source footage at the higher resolution. Keeping your project in FULL HD allows more flexibility for delivery options including Blu Ray and Web distribution. 720p is a valid option if you’re concerned about filling up your memory cards too quickly, or you’re lacking in computer power or hard drive space. This is also an acceptable quality for streaming web videos, and even for broadcast television. 1080i should be avoided if your final destination is the web, as all videos are ultimately played back using progressive frames. If you’re ultimate destination is broadcast TV, then 1080i could still be a good option. No matter which resolution you choose, it’s a good idea to shoot some test footage, and try working with it on your computer system. Shoot a test project, work with the footage in your editing software, and export it to a few different deliverable formats. This is the best way to ensure you won’t get any surprises along the way.
