Posted by Chopper3 at dis.ncr-css.co.uk on June 20, 2000 at 12:20:52:
In Reply to: Re: Shouldn't the retails... posted by Kuku on June 20, 2000 at 11:07:10:
When people talk about film ratios all they're talking about is how rectangular the picture is.
Ratios are made up of two numbers the horizontal and then the vertical.
Take a perfect square of one foot wide by one foot high, that would have a ratio of 1:1.
If you had a square that was two foot wide by two foot high they screen is four times bigger but the ratio remains 1:1.
A rectangle that was two foot wide by one foot high would have a ratio of 2:1.
The same is true of a rectangle that is four foot wide by two foot high, the ratio is still 2:1.
The horizontal number is the only number that changes as the vertical ratio is always calculated down to the number one.
A rectangle that is three foot wide by one foot high would therefore have the ratio of 1.5:1
Well that's the basics, in actual fact there are certain ratios that get used more than most. These are;
4:3 - (a.k.a. "Full Screen" & "Full Frame") Most "normal" TV screens use a 4:3 ratio, get your tape measure out and you can see that for ever 4 inches of width there will be 3 inches of height.
"16x9" - This is a particular name for a ratio (actually 16 divided by 9 is 1.7778:1) used on most "widescreen" TV sets and also is the official ratio for the new "High-Definition" TV sets.
1.85:1 - This is a very popular ratio for film work as it's a very easy ratio to shoot with on 16mm and 35mm cameras, you only need spherical lenses to do this. As this ratio is very similar to the 1.7778 of "16x9" many people call this ratio "widescreen" just for the sake of inaccuracy!
2.35:1 - (a.k.a. "Scope" & "Anamorphic") This is about the widest picture you will generally see in production today and uses an "Anamorphic" lens to force a wide picture into the same framespace as a 1.85:1 film. Obviously when viewed directly everything will appear tall and thin, a reverse lens is used to project this film and "correct" the ratio difference. The biggest downside to this format is that you are "matting" (leaving black) around half of each frame. This means that when the picture is projected the grain can be more apparent. It was for this reason that many of the more epic films of the 50's, 60's & 70's chose to use 70mm film (also generally a 2.35:1 format) to more accurately reflect the lighting and detail of a 2.35:1 scene.
2.78:1 - Used rarely and mostly in the 40's, 50's and 60's. This is an extremely widescreen picture used in "Ben Hur" if I remember. The director has to have a very good reason to use this ratio as it's mis-use is bloody irratating to the eyes.
So there you go.
PBM.