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-   -   Air show - progressive or interlaced? (https://www.dvinfo.net/forum/sony-xdcam-ex-pro-handhelds/123234-air-show-progressive-interlaced.html)

Simon Frances June 7th, 2008 02:02 AM

Air show - progressive or interlaced?
 
Hi,

Looking for some recommended setting for shooting at an air show, i.e. Shutter Speed, whether to shoot Progressive or Interlaced and what Picture Profile to use.

I was leaning towards; Shutter, 1/50th, Interlaced and Bill Ravens PP True Color. Any other tips welcomed.

Thanks in advance,
Simon

Peter Kraft June 7th, 2008 02:31 AM

Depends
 
There is no ultimate answer, I'm sorry. Depends what you want to do the your video material and what your shooting conditions are.
Fact is that you have relatively fast moving objects (aircraft), which are not MPEG2's strength.
There are two ways to circumvent this situation,
a) if your camera does not move while the aircarft move, shoot from a very tight angle,
b) if you only can shoot from, say, a 90 degree angle, pan with the aircraft, trying to keep it in the middle of your viewfinder while you pan.
Such the background looses sharpness (inherent downside of MPEG 2, but as the main interest of the sequence are the aircraft, this slight loss in sharpness does not really matter.
Shoot at the highest possible datarate which minimizes artefacts due to fast moving objects in an MPEG2 GOP video.

While filming the Paris airshow last year, I opted for 1080i50, so yes, interlaced was my best bet. As other shots from Paris were progressive, I sent my source material through a de-interlacer while in post, which converted the interlace artefacts into motion blur. This made it possible to get both worlds in one movie.

Hope this helps,
P.

Craig Seeman June 7th, 2008 10:45 AM

It may be that 720p50 is your best bet. You'll get good temporal resolution with 50 progressive frames and well as good spacial resolution (compared to 50 interlaced frames which is only showing half the lines at any 1/50th).

Given that the data rate is the same whether 720 or 1080, 720 applies that data over a smaller frame so the codec will hold up better.

Here in the "states" many HD sports channels opt for 720p60 for the above reasons.

Robert Young June 7th, 2008 01:27 PM

I have the same experience as Peter with action shots. I shoot 1080 60i HQ, deinterlace on capture and edit as 30p.
If you shoot 720 30p you will get more data per frame than from 1080 format, but it seems to me shooting 720 60p, you are spreading the data stream over twice as many frames. I don't know what the math is exactly, but you may actually get less data per frame than with 1080 60i/30p. Nonetheless, you should get good action capture and avoid interlace issues.

Craig Seeman June 7th, 2008 04:08 PM

Deinterlacing, by the nature of the beast, generally isn't as good as shooting progressive.

It's not data per frame. It's data spread across the frame size (and frame rate). 1280x720 is 921,600 pixels whereas 1920x1080 is 2,073,600 pixels so at 720 you can have more data per pixel on a given frame. Given interlace for 1080 it would be 1920x540 which is 1,036,800 which is much closer

So at any given 1/60th assuming 1080i60 or 720p60 you have
1,036,800 for 1 field (1/60) of 1080i
921,600 for 1 frame (1/60) of 720p

So 720p60 still looks to be a bit more data per pixel, the same temporal motion (60 units of motion per second), progressive frames. At a given 60th of a second 1080i60 is actually 540 lines compared to 720p60 720 lines.

While one can argue for 1080i60 vs 720p60 one can't say that 1080i60 is "better" than 720p60. In fact they have the same temporal motion. 720 has slightly more data per pixel and it's progressive frames which to some eyes look better than interlaced frames.

Here's an interesting read.
http://www.bluesky-web.com/numbers-mean-little.htm

Gints Klimanis June 7th, 2008 06:00 PM

Quote:

Originally Posted by Robert Young (Post 889672)
I have the same experience as Peter with action shots. I shoot 1080 60i HQ, deinterlace on capture and edit as 30p.
If you shoot 720 30p you will get more data per frame than from 1080 format, but it seems to me shooting 720 60p, you are spreading the data stream over twice as many frames.

At higher frame rates, the difference between frames will be less for material of this type. If the entire frame is animated, you're right.

Robert Young June 7th, 2008 07:05 PM

Craig
You are absolutely right, it is data per pixel I meant to be referring to.

Simon Frances June 10th, 2008 03:30 PM

Thanks guys for all your comments. Just need to get a remote zoom control now. :)

Ben Ruffell June 10th, 2008 04:49 PM

I just worked on this Airshow.

http://www.youtube.com/watch?v=15w3cxXzDzs

We shot it 50i mostly F900's.

Gave lots of options in post.

Dean Sensui June 11th, 2008 04:50 AM

Something to ponder: Prior to the 1950s all aviation footage was shot at 24p: 16mm film or bigger. The movies "Twelve O'Clock High", "The Battle of Britain", "Blue Thunder" and "Top Gun" were shot at 24 fps.

Interlaced is not an essential but an option. Depends on what you want it to look like.

Good luck and enjoy the show!

Steve Connor June 11th, 2008 10:03 AM

Quote:

Originally Posted by Ben Ruffell (Post 891095)
I just worked on this Airshow.

http://www.youtube.com/watch?v=15w3cxXzDzs

We shot it 50i mostly F900's.

Gave lots of options in post.

Great footage - I shoot a lot of airshows and we never get that sort of access for air-to-air filming. Plus the fact the scenery in that area is stunning?

BTW Simon - shoot interlaced, also when you are filming flying aircraft make sure you have the heaviest tripod possible and use auto iris. (100 + Airshows under my belt!)

Ben Ruffell June 12th, 2008 05:22 PM

It was this show: http://www.warbirdsoverwanaka.com/
In New Zealand - I think the next one is 2010.

The aerials were shot with a CineflexHD mounted in the back of a Hercules. (I was up there also, shooting some behind the scenes and cockpit stuff - it was pretty cool).

I would tend towards interlaced. I would also keep manual iris control, maybe Pola on the lens, but it all depends on your camera, your access and what you are shooting for...


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