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to 24p or not to 24p--this is the question


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#1 Ruby Gold

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Posted 04 March 2007 - 08:34 PM

Hi there. I'm relatively new to my DVX100b and have only shot in 60i for my projects with it. Mostly I've chosen this because a) it's familiar; B) 60i handles motion more cleanly; and c) I was scared of the commitment to 24p shooting and editing.

I keep hearing how beautiful the filmic look of 24p can be, and I have a new project coming up, so I went out and shot some test stuff in 24p and 60i just to compare. I do see what everyone is talking about in terms of the creaminess of the colors and the filmic look of the motion. What I also noticed on the stuff I shot is that the 24p looked a bit dark to my eye, somewhat 'slow motion-y' when focusing on a flag waving in the wind, and it seemed as if sharp focus was harder to achieve than in 60i.

My questions to the forum are:
I noticed that the 24p setting has a 1/24 shutter speed. Does 24p 'work' with a faster shutter speed and wd that help with the 'dark' look or does 24p need to be shot at 1/24? Does one typically need to use a lower f-stop with 24p than 60i--or, is the darker image I'm referring to not typically a problem for most folks?

Some of the footage I shot in 24p seemed to be a bit out of focus where the stuff I shot in 60i with the same settings was nicely focused. I had the camera was on autofocus most of the time, so I'm wondering if the difficulty with focus is because of the slower shutter speed in 24p? Or some other factor related to 24p? Or using auto instead of manual focus? I was doing street shots, so it seemed easier to just put it on auto focus while shooting these tests. Any illumination here greatly appreciated.

Last, but not least. I edit in PPro 1.5. If I edit on a 24p timeline, can 60i footage be used on the same timeline as the footage shot in 24p? Conversely, if I edit on a 60i timeline, can 24p footage be used along with 60i? I'm thinking of shooting interview footage in 24p and my outdoor cutaways with more motion in them in 60i, but don't know if you can mix the two on one timeline. Again, any help here greatly appreciated.
Thanks!
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#2 David Mullen ASC

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Posted 04 March 2007 - 08:41 PM

There's no reason why you can't expose 24P to be the same image brightness as 60i. You may have been switching between the two modes but not adjusting exposure for differences in shutter speed, etc. There's no reason why 24P should be any darker.

A film camera at 24 fps has a shutter speed of 1/48th of a second because of the 180 degree shutter. So using a shutter speed anywhere near 1/48th (like 1/50th or even 1/60th, maybe 1/32nd) would match that look the best.

1/24th at 24P, though it gains you another stop of exposure compared to 1/48th, makes the motion smearier. Now that may help you reduce the strobiness of 24P motion, but the smeariness can remind you of 60i interlaced-scan motion since 60i at 1/60th and 24P at 1/24th are both essentially "shutterless" (no dark interval between exposures.)
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#3 Jim Feldspar

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Posted 05 March 2007 - 08:32 AM

Some of the footage I shot in 24p seemed to be a bit out of focus where the stuff I shot in 60i with the same settings was nicely focused. I had the camera was on autofocus most of the time, so I'm wondering if the difficulty with focus is because of the slower shutter speed in 24p? Or some other factor related to 24p? Or using auto instead of manual focus? I was doing street shots, so it seemed easier to just put it on auto focus while shooting these tests. Any illumination here greatly appreciated.

Thanks!
[/quote]

I believe that autofocus responds more slowly
with slower shutter speeds because the camera is getting information less frequently
and thus takes longer to adjust/update.

I'd be careful anyway with autofocus anyway. I like Panasonic cameras but I've had a couple
of soft faces because the autofocus grabbed onto the lines in the brick wall behind the person.



Some of the footage I shot in 24p seemed to be a bit out of focus where the stuff I shot in 60i with the same settings was nicely focused. I had the camera was on autofocus most of the time, so I'm wondering if the difficulty with focus is because of the slower shutter speed in 24p? Or some other factor related to 24p? Or using auto instead of manual focus? I was doing street shots, so it seemed easier to just put it on auto focus while shooting these tests. Any illumination here greatly appreciated.

Thanks!
[/quote]

I believe that autofocus responds more slowly
with slower shutter speeds because the camera is getting information less frequently
and thus takes longer to adjust/update.

I'd be careful anyway with autofocus anyway. I like Panasonic cameras but I've had a couple
of soft faces because the autofocus grabbed onto the lines in the brick wall behind the person.
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#4 Ruby Gold

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Posted 05 March 2007 - 05:21 PM

Thanks a lot for the great feedback you guys!
Ruby
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Media Blackout - Custom Cables and AKS

Rig Wheels Passport

Visual Products

Willys Widgets

Paralinx LLC

Ritter Battery

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