16x9 Aspect Ratio

[Alberto Larios-Saavedra]

I've read in the past that the frame size for the 19x9 aspect ratio is 1.77:1; however, today I was browsing trough the 8th edition of the A.C. manual and read that the frame size is 1.78:1 (page 19). Which one is correct?

 

Thanks,

 

Al

[Guest dpforum1968]

Not sure, sorry.

 

DC

[David Mullen ASC]

Come on, this is grade school math! Divide 16 by 9 and you get 1.7777777 (don't know how many more sevens...) That is usually rounded up to 1.78 but you could say 1.77 too.

[John Sprung]

you get 1.7777777 (don't know how many more sevens...) 

<{POST_SNAPBACK}>

The mathematically correct answer is infinitely many sevens. So, use as many sevens as you want, just replace the last one with an eight. As a practical matter, though, the difference between 1.78 and 1.778 is a fraction over two pixels in 1920 x 1080 HD, not enough to worry about. The long standing practical tradition is to express aspect ratios to two decimal places.

 

So, it's more correct to say 1.78, but not worth jumping all over somebody who uses 1.77. There's a bigger discrepancy in scope. A lot of people still talk about 2.35:1, although very early on it was discovered that that aperture would put visible edges of negative splices on the screen. The height of the aperture was reduced to hide the splices, which changed the ratio to 2.39:1. Some people also say 2.40, but if you read the standards and do the math, it's really 2.39.

 

 

 

-- J.S.

[Alberto Larios-Saavedra]

Come on, this is grade school math!  Divide 16 by 9 and you get 1.7777777 (don't know how many more sevens...)  That is usually rounded up to 1.78 but you could say 1.77 too.

<{POST_SNAPBACK}>

I know that you can round it up to 1.78, but I asked the question because I didn't know if it made a difference to go either way, besides there's no consistency when people refer to the term and I was a little confused, that's all.

[Alberto Larios-Saavedra]

The mathematically correct answer is infinitely many sevens.  So, use as many sevens as you want, just replace the last one with an eight.  As a practical matter, though, the difference between 1.78 and 1.778 is a fraction over two pixels in 1920 x 1080 HD, not enough to worry about.  The long standing practical tradition is to express aspect ratios to two decimal places. 

 

So, it's more correct to say 1.78, but not worth jumping all over somebody who uses 1.77.  There's a bigger discrepancy in scope.  A lot of people still talk about 2.35:1, although very early on it was discovered that that aperture would put visible edges of negative splices on the screen.  The height of the aperture was reduced to hide the splices, which changed the ratio to 2.39:1.  Some people also say 2.40, but if you read the standards and do the math, it's really 2.39.

-- J.S.

<{POST_SNAPBACK}>

 

Thanks John. That answers my question.

 

Al

[Michael Nash]

"Tomato, tomahto, potato, potahto. Let's call the whole thing off..."