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-   -   ASpect ratio (https://www.dvinfo.net/forum/open-dv-discussion/4088-aspect-ratio.html)

Chet Hardin October 3rd, 2002 07:55 AM

ASpect ratio
 
Can someone explain to me this ratio? I shoot with an xl-1. In what aspect ratio am I capturing?

Dave Grey October 3rd, 2002 10:26 AM

That depends...
 
That depends on your setup.

The XL1 shoots both 4:3 ('standard' video aspect... like on your square television) and 16:9 ('wide' aspect like on your rectangular television).

With the XL1 you also have the option of various optical anamorphic (wide) adapters, you lucky dog.

Aspect ratio in general defines the relationship between the X and Y axes of the image; the ratio of width to height.
So a screen 4" wide and 3" high would have an aspect of 4:3, as would a screen 20" high and 15" wide.

Hope this helps.

lyd

Josh Bass October 3rd, 2002 11:16 AM

I got one related to this: What's the deal with the 3 numbered ratios: 2:33:5 or something like that (I know that's not real world example).

Dave Grey October 3rd, 2002 11:40 AM

If you mean numbers like 4:1:1, 4:2:0, 4:2:2, etc, these refer to the sampling rates emplyoyed by different formats.

[I'm deleteing the rest of this post as I was wildly missing the point and generally taking up space -lyd]

lyd

Josh Bass October 3rd, 2002 12:16 PM

No sir. . .had no idea about the sample rates. I just thought I seen people write "This was shot in 2:4:5 or something like that. Mabye not. Probably not.

Jeff Donald October 3rd, 2002 01:10 PM

Josh,

Those are film size aspect ratios, like 2.35:1 or 1.66:1. this site has some simple examples http://www.thedigitalbits.com/articles/anamorphic/aspectratios/widescreenorama.html

Jeff

Chet Hardin October 3rd, 2002 01:30 PM

1.33:1
 
Yes, that is what I was wondering about. Thanks Josh for steering this conversation more in the course I had intended.
Jeff. I went to that site. Is Mini-Dv 1.33:1? It seems like (I asked about this awhile ago) TV safe area, 4x3, cuts off some of the image...
Thanks.

Jeff Donald October 3rd, 2002 01:41 PM

Yes, 1.33:1 is 4:3 ratio, same as NTSC video. Consumer TV sets generally do not display the entire picture. They overscan the image (part of the picture is blocked by the cabnet) as per the NTSC specifications. Early CRT's had quite a curve to them due to manufacturing limitations. The cabnets hid flaws in the CRT. Today, TV sets still overscan and cut off part of the image. Because the spec has some leeway some TV's cut off more of the image than others, but remain in spec. There is nothing you can do except follow safe title and safe action guides.

Jeff

Dave Grey October 3rd, 2002 03:40 PM

Ah-ha.
 
I see... sorry for flying off in the wrong direction. I got excited thinking I might have somthing to contribute. I should have known better. :)

So, is there any historical reason why film uses the unit ratio while television uses the the ratio expressed as integers?

4:3 seems alot more intuitive to me than 1.33:1

lyd

Jeff Donald October 3rd, 2002 03:59 PM

No problem, lyd. I can see you've been to Adam Wilt's site (and it has paid off). If I had to guess I'd say it's tradition. Film has always been referred to in that manner. It might also help deferentiate film and video (video is always whole number 16:9, 4:3).

Jeff


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