Aspect Ratio and Resolution for ultrawide screen, 21:9 and 16:9

Introduction and Ratio Explained:

Ratio (in reference to an image/frame size for video) is simply height in relation to width. For example, 16:9 is 16 units (of measurement) high to 9 units wide, or 16/9 (16 divided by 9) = 1.78 (1.78 units for 1 unit).

Resolution of an image is its physical size, but it will have a ratio and the ratio is different from resolution. For example, an image can be 1000 by 1000 pixels and that is its resolution, but its ratio is 1:1. So if it’s 2000 by 2000 pixels its ratio is still 1:1. For example 1/1=1 2/2=1 3/3=1 and so on.

World of Filmmaking and Animation:

In the world of filmmaking and animation there are many different types of ratio and resolution (for example see an extensive list here!)

However, there are are several very popular and most commonly used ratios. The most commonly used today is 16:9 and provides a wide screen image. There is also ultrawide screen (ultrawide is an aspect ratio greater than 2. so 2.35:1 for example) of which is sometimes referred to as 21:9 and for a enlightening article (from Empire magazine) that goes into more detail in the history of ratio please click the link here.

An Important note on 21:9:

21:9 is more a marketing term for ultrawide screen aspect ratios and there are numerous ratios that full into the ultrawide image size domain. These ratio’s have changed over the years and are likely to change in the future, but listed below are some of the most popular widescreen formats today.

• 2.35:1
• 2.37:1
• 2.39:1

Many modern movies are made using the aspect ratio of 2.35:1 or 2.39:1 . 21:9 works out as 2.33:1 and there are further details on this below.

Ratios and Resolutions:

Below is a list of ratios and resolutions commonly used.

16:9 Ratio and Resolutions:
HD: 1280 x 720
FHD: 1920 x 1080
UHD: 3840 x 2160

16:9 Further Info:
16/9 = 1.78 (1.78 units for 1 unit).

Ultrawide Screen Ratio and Resolutions:

2.35:1

HD: 1920 x 816
UHD 4k: 3840 x 1634
UHD 8k: 7680 x 3268

2.37:1

HD: 1920 x 810
UHD 4k: 3840 x 1620
UHD 8k: 7680 x 3240

2.39:1

HD: 1920 x 802
UHD 4K: 3840 x 1606
UHD 8k: 7680 x 3212

21:9 Further Info:

21:9 works out as 2.33:1 and is not a ratio commonly used as an ultrawide format. It is though equated with the more common 2.35:1 format – which is an ultrawide screen format. Of course you could use 2.33 or any darn ratio you want! But best to stick to standardised ratios, especially if going to cinema projection, or if not using a common ratio make sure the cinema projector(s) knows what ratio your movie needs to be projected in!

21:9 or 2.33:1 Resolutions (although you may never use these and I would recommend staying with 2.39.1, 2.37.1 or 2.35.1)

HD: 1280 x 549
FHD: 1920 x 823
UHD: 3840 x 1646

(Note: For some unknown reason, Youtube seems to recognise 21:9 UHD at 3840 x 1600 – so if uploading to Youtube, it’s worth testing out both resolutions before you make your final upload).

Something a little confusing:

When looking at resolutions for 2.39:1 for example, you may find some studios/companies reference 2.39:1 UHD 4k at 3840 x 1606 and others at 3840 x 1608. This is because different rounding has been used!

Filming or Rendering:

If you’ve already filmed or rendered your footage in 16:9 then you can crop off the top and bottom of the image if changing to an ultrawide screen ratio, but this will give you borders at the top and bottom of the image. Also there will likely be some cropping of details in the shot that may be required for the movie to make sense.

So this should be avoided, and either shot in 16:9 or a ultrawide screen format to begin with. However, if you plan to shoot 16:9 and then crop to ultrawide screen ratio, then make sure you shoot or render with safety guides on the camera screen, or at least keep it in mind when filming/rendering.

Widescreen Ratios:

Widescreen ratios in most common use are 16:9 (1.78:1) or 1.85:1. Obviously 1.85:1 is wider than 16:9 but not quite at an ultrawide screen ratio. This is a format you may also wish to consider and for a bit more info please see this post from the cinematographer Neil Oseman

What one should you use?

The ratio you should use is a subjective matter and may come down to just the artistic look you are going for. 2.39:1 is great for landscapes and wide cinematic shots, but you may want to go with 2.35:1 to give the film something a little more intermit or even 1.85:1. Of course, if working for a studio or company they may already have a set ratio to film in, or if it’s just for online you may wish to stick with 16:9.