in-camera crop is actually 1.66:1 ?
- Thread starter shAi
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Re: in-camera crop is actually 1.66:1
Re: in-camera crop is actually 1.66:1
[quote author=shai link=board=Events;num=1080173677;start=0#2 date=03/24/04 at 23:36:56]should i ask if it's the same in NTSC?
[/quote]
Nope. Mine is 1.8181818181818 based on 1:1 pixel aspect ratio, copied/pasted in photoshop and cropped to active area, or 1.81875 based on NTSC DV Standard .9091 pixel aspect ratio, just looking at either the capture screen or monitor display in Vegas 4.0e ;D
-Rodger
Re: in-camera crop is actually 1.66:1
[quote author=shai link=board=Events;num=1080173677;start=0#2 date=03/24/04 at 23:36:56]should i ask if it's the same in NTSC?
[/quote]
Nope. Mine is 1.8181818181818 based on 1:1 pixel aspect ratio, copied/pasted in photoshop and cropped to active area, or 1.81875 based on NTSC DV Standard .9091 pixel aspect ratio, just looking at either the capture screen or monitor display in Vegas 4.0e ;D
-Rodger
Barry_Green
Moderator
Re: in-camera crop is actually 1.66:1
Re: in-camera crop is actually 1.66:1
Really? Hmmm. Weird.
I'm not in front of that system right now, but from my recollection, in Vegas, my letterbox footage is actually less-letterboxed than the Vegas 16:9 crop mode. Seems like 1.66 should be about right for what it delivers. I'll try to remember to check it later.
Wonder if they tightened it up on the 100A?
Re: in-camera crop is actually 1.66:1
Really? Hmmm. Weird.
I'm not in front of that system right now, but from my recollection, in Vegas, my letterbox footage is actually less-letterboxed than the Vegas 16:9 crop mode. Seems like 1.66 should be about right for what it delivers. I'll try to remember to check it later.
Wonder if they tightened it up on the 100A?
Mike_Donis
Veteran
Re: in-camera crop is actually 1.66:1
Re: in-camera crop is actually 1.66:1
I know that my NTSC model didn't seem like true 16:9...so when I measured it all out (in photoshop) it actually came to 1.72:1...
Now how I noticed that from 1.78:1 (true 16:9) is beyond me. But I did!
Re: in-camera crop is actually 1.66:1
I know that my NTSC model didn't seem like true 16:9...so when I measured it all out (in photoshop) it actually came to 1.72:1...
Now how I noticed that from 1.78:1 (true 16:9) is beyond me. But I did!
Barry_Green
Moderator
Re: in-camera crop is actually 1.66:1
Re: in-camera crop is actually 1.66:1
Okay, letterbox on the NTSC DVX100 (original model) adds 54-pixel bars on the top and bottom of the frame. That leaves a 720 x 372 image in the middle.
Using a strict interpretation of 4:3 (which would mean a basic frame size of 640 x 480) you get 1.72:1. However, DV video isn't a pure mathematical 4:3, because TV screens provide for a few pixels more...
Using the Vegas aspect ratio of .9091 you'd get (655/372) 1.76:1. That's within a pixel or two of being exactly 16:9.
Using the Vegas cropping preset of 16:9, it crops the letterbox bars exactly, and one pixel more (i.e., Vegas thinks the letterbox bars should be one pixel thicker than the DVX thinks they should be).
So, it'd be fair to say that the letterbox bars in the original NTSC DVX100 are almost exactly 16:9, maybe just the tiniest bit taller, at 1.76:1 instead of 1.7777777:1.
So, Rodger (or anyone else with a 100A) it'd be mildly interesting to know how many pixels thick the letterbox bars are on the 100A, to see if they changed it any. (If you're using Vegas, be sure to un-check "simulate device aspect ratio" so you get a pixel-accurate export instead of a scaled/resized export).
Re: in-camera crop is actually 1.66:1
Okay, letterbox on the NTSC DVX100 (original model) adds 54-pixel bars on the top and bottom of the frame. That leaves a 720 x 372 image in the middle.
Using a strict interpretation of 4:3 (which would mean a basic frame size of 640 x 480) you get 1.72:1. However, DV video isn't a pure mathematical 4:3, because TV screens provide for a few pixels more...
Using the Vegas aspect ratio of .9091 you'd get (655/372) 1.76:1. That's within a pixel or two of being exactly 16:9.
Using the Vegas cropping preset of 16:9, it crops the letterbox bars exactly, and one pixel more (i.e., Vegas thinks the letterbox bars should be one pixel thicker than the DVX thinks they should be).
So, it'd be fair to say that the letterbox bars in the original NTSC DVX100 are almost exactly 16:9, maybe just the tiniest bit taller, at 1.76:1 instead of 1.7777777:1.
So, Rodger (or anyone else with a 100A) it'd be mildly interesting to know how many pixels thick the letterbox bars are on the 100A, to see if they changed it any. (If you're using Vegas, be sure to un-check "simulate device aspect ratio" so you get a pixel-accurate export instead of a scaled/resized export).
Re: in-camera crop is actually 1.66:1
Re: in-camera crop is actually 1.66:1
All I did to get the 1.81??? ratio was divide Vegas' capture width which is 873 (or 872 take your pick) by the capture hight of 480 to get the ratio of 1.81??? Fooled around with it in photoshop and got 1.81818181. But either way its not 1.78 more like 1.818. Cropped image size is the same as on the DVX 100 -- 372 pixels high.
I don't know about a 4:3 (640x480) using a different ratio to to achieve 16:9 then you would at 720x480. Seems to me 16:9 is 16:9 no matter what the capture resolution is. But then again, what do I know... Maybe in this regard not too much ;D.
-Rodger
Re: in-camera crop is actually 1.66:1
All I did to get the 1.81??? ratio was divide Vegas' capture width which is 873 (or 872 take your pick) by the capture hight of 480 to get the ratio of 1.81??? Fooled around with it in photoshop and got 1.81818181. But either way its not 1.78 more like 1.818. Cropped image size is the same as on the DVX 100 -- 372 pixels high.
I don't know about a 4:3 (640x480) using a different ratio to to achieve 16:9 then you would at 720x480. Seems to me 16:9 is 16:9 no matter what the capture resolution is. But then again, what do I know... Maybe in this regard not too much ;D.
-Rodger
Bart_Boge
Well-known member
Re: in-camera crop is actually 1.66:1 ?
Maybe I am a complete idiot, but I am not understanding the aspect ratio math here. Please walk me through it.
720/480 =1.5:1, or 4:3
720/372 = 1.93548:1 (how does this equal 1.7777:1?)
Is my math screwed up by the pixels themselves not being perfectly square? What is their ratio, if not square?
I have been told that if I use my 7200G with letterbox I'll get 2.37:1, or just a frog-hair off of old-school CinemaScope aspect. I believe it, but I would like to understand the calculations.
HELP?!
(went to a liberal arts college and only took one lousy math class)
Maybe I am a complete idiot, but I am not understanding the aspect ratio math here. Please walk me through it.
720/480 =1.5:1, or 4:3
720/372 = 1.93548:1 (how does this equal 1.7777:1?)
Is my math screwed up by the pixels themselves not being perfectly square? What is their ratio, if not square?
I have been told that if I use my 7200G with letterbox I'll get 2.37:1, or just a frog-hair off of old-school CinemaScope aspect. I believe it, but I would like to understand the calculations.
HELP?!
(went to a liberal arts college and only took one lousy math class)
Barry_Green
Moderator
Re: in-camera crop is actually 1.66:1 ?
The pixels aren't square. They're .9091:1.
The pixels aren't square. They're .9091:1.
Mike_Donis
Veteran
Re: in-camera crop is actually 1.66:1 ?
Well, I'm too lazy to figure out the calculations...but if you take any 16:9 matted footage, and play in in a 16:9 monitor (with no changes made to the ratio, so you're just 'stretching' the footage) it'll look just like cinemascope.
Well, I'm too lazy to figure out the calculations...but if you take any 16:9 matted footage, and play in in a 16:9 monitor (with no changes made to the ratio, so you're just 'stretching' the footage) it'll look just like cinemascope.
Bart_Boge
Well-known member
Re: in-camera crop is actually 1.66:1 ?
OK, I think I finally get it now. There is a bit of a discrepancy between the theoretical and the actual results. Check to make sure I'm getting this right:
THEORETICALLY:
Regular 4:3 aspect = 1.333333:1
Standard 16:9 aspect = 1.777777:1
Running one on top of the other = 2.37037:1
REAL WORLD:
16:9 Anamorphic using 7200G lens:
480 x (480 x 1.77777) = 480 x 854 when stretched for playback
Using the 7200G + in-camera letterbox (54 pxls off top & bottom):
372 x 854, which comes out to 2.2956989:1
So, if one were "claiming" a widescreen aspect for productions shot this way, which would be more accurate? 2.37:1 or just 2.3:1? In theory the aspect is 2.37:1, but in practice it is slightly narrower. Neither is exactly 2.35:1 like real CinemaScope, but both are extremely close (either 372 x 874 or 363 x 854 would be closer to 2.35:1).
Am I getting all this right?
I know, I know. We are talking about being 9 horizontal lines or 20 vertical lines off, which accounts for a whopping 2.4% of the entire image. WHO CARES?! Well, I just want to have my facts straight. Helps when the lawyers show up on my doorstep to claim "breach of contract" or "false advertizing" for delivering 2.2956989:1 instead of the promised 2.37037037:1.
OK, I think I finally get it now. There is a bit of a discrepancy between the theoretical and the actual results. Check to make sure I'm getting this right:
THEORETICALLY:
Regular 4:3 aspect = 1.333333:1
Standard 16:9 aspect = 1.777777:1
Running one on top of the other = 2.37037:1
REAL WORLD:
16:9 Anamorphic using 7200G lens:
480 x (480 x 1.77777) = 480 x 854 when stretched for playback
Using the 7200G + in-camera letterbox (54 pxls off top & bottom):
372 x 854, which comes out to 2.2956989:1
So, if one were "claiming" a widescreen aspect for productions shot this way, which would be more accurate? 2.37:1 or just 2.3:1? In theory the aspect is 2.37:1, but in practice it is slightly narrower. Neither is exactly 2.35:1 like real CinemaScope, but both are extremely close (either 372 x 874 or 363 x 854 would be closer to 2.35:1).
Am I getting all this right?
I know, I know. We are talking about being 9 horizontal lines or 20 vertical lines off, which accounts for a whopping 2.4% of the entire image. WHO CARES?! Well, I just want to have my facts straight. Helps when the lawyers show up on my doorstep to claim "breach of contract" or "false advertizing" for delivering 2.2956989:1 instead of the promised 2.37037037:1.
Barry_Green
Moderator
Re: in-camera crop is actually 1.66:1 ?
First of all, keep in mind that DV doesn't use square pixels, so your numbers may not be accurate anyway.
Secondly, the "actual" widescreen image has changed many times over the years. It's been as wide as 2.66:1 (like Spartacus) and as narrow as 2.2:1. For a while it was 2.35, but the current spec is actually for 2.39:1. And, the accuracy of that is all determined by the accuracy of the gate in the projector where you're watching the film...
If you're in the ballpark of 2.35, you're going to be fine. At DV resolutions, one pixel one way or the other is enough to change the ratio.
First of all, keep in mind that DV doesn't use square pixels, so your numbers may not be accurate anyway.
Secondly, the "actual" widescreen image has changed many times over the years. It's been as wide as 2.66:1 (like Spartacus) and as narrow as 2.2:1. For a while it was 2.35, but the current spec is actually for 2.39:1. And, the accuracy of that is all determined by the accuracy of the gate in the projector where you're watching the film...
If you're in the ballpark of 2.35, you're going to be fine. At DV resolutions, one pixel one way or the other is enough to change the ratio.
Re: in-camera crop is actually 1.66:1 ?
And there's still an awful lot of 1.85 out there. Shyamalan, I'm looking your way . . .
And there's still an awful lot of 1.85 out there. Shyamalan, I'm looking your way . . .
Barry_Green
Moderator
Re: in-camera crop is actually 1.66:1 ?
Last I heard, I believe the ratio was about 50% 2.39, 50% 1.85. And, of course, 1.85 is only the standard projection gate in America, in Europe the standard is 1.66...
Last I heard, I believe the ratio was about 50% 2.39, 50% 1.85. And, of course, 1.85 is only the standard projection gate in America, in Europe the standard is 1.66...
SoerenM
Well-known member
Re: in-camera crop is actually 1.66:1 ?
At least for PAL I've got some of the regular resolutions composed together in one pic.. for details just hoover your mouse over region of interest ;-P
http://www.all-digital.de/resolutions.htm
(don't ask.. I just don't get the rest of my website finished ;o)
At least for PAL I've got some of the regular resolutions composed together in one pic.. for details just hoover your mouse over region of interest ;-P
http://www.all-digital.de/resolutions.htm
(don't ask.. I just don't get the rest of my website finished ;o)