Help Understanding Aspect Ratio?

Recently made my first logo animation for a client. They are happy with it, but it’s in 1080p 1:1 ratio and their projector projects at a 4:3 ratio (this is where it will mostly be shown on). So it shows up as kind of a wide-screen clip instead of filling the whole screen.

I’ve tried to understand the aspect ratios and such in the Dimensions drop down on the render tab in Blender, but I’ve got no luck.

Under the Render Presets I’ve clicked TV NTSC 4:3 but the aspect ratio changes to 10:11. If the preset is TV NTSC 4:3 shouldn’t the aspect ratio be 4:3 instead of 10:11?

tl;dr : Could someone just explain aspect ratios for rendering in blender and the correct camera presets as well?

The Aspect Ratio settings is generally used for TV formats where this is the size ratio of non square pixels

http://wiki.blender.org/index.php/Doc:2.6/Manual/Render/Output

Yeah, but why is TV NTSC 16:9 4:3.3 par? What does the 16:9 mean then?

16:9 is the aspect ratio for wide screen image resolutions, such as 1080 and 720, which can be progressive § or interlaced (i). FullHD resolution is 1920x1080: 1920/16 = 120 and 120*9 = 1080.

Old widescreen NTSC TV is marked to have a 4:3.3 pixel aspect ratio.

Thanks for explaining!

This is different then the aspect ratio shown in render settings, btw. 4:3/16:9/2.35:1 etc are screen aspect ratios. It’s the ratio of screen width to screen height, as in JA12’s example. The thing in render settings is something else, and that is the width:height ratio if each individual pixel. For pre-HD TV formats, pixels are (obnoxiously) not squares, they’re rectangular. The standard NTSC frame is a 4:3 aspect ratio (divides out to 1.333:1, since 4/3=1.333). So the screen is 1.33 times wider than it is tall. But the pixel dimensions are 720x480. 720/480 isn’t 1.33, it’s 1.5. The reason for this is that the pixels are not squares. They are rectangles, their width is only 91% of their height. (this multiplies out to 10:11 if you use whole numbers). Even more fun: 16:9 NTSC is STILL 720x480, they just turned the pixels sideways!

If you’re not having fun yet, it gets even better! The projector probably isn’t 720x480 with non-square pixels, even though it uses a 4:3 frame. It most likely follows the old computer monitor formats from back when most monitors were 4:3. The native resolution of the image chip is probably 1024x768 or 800x600. Same relative dimensions, but totally different pixel grid.

4:3 1080p is 1440x1080, and that’s probably the resolution you want your animation in. (or a smaller res if you want, like the aforementioned 1024x768). You can either re-render or just crop the existing one.

Whoa. That’s obnoxious! Thanks for the explanation! I definitely didn’t realize this.