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Sony HVR-Z7 / HVR-S270
Handheld and shoulder mount versions of this Sony 3-CMOS HDV camcorder.


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Old April 26th, 2008, 12:35 PM   #1
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30P Choppy?

I've been playing around with the 30p mode on the Z7. Should it be a little choppy when panning left to right? I don't think this will be a real problem for the Ceremony, but it might not be so great during the reception. Has anyone had any issues yet? Also, do you lose any of the low-light sensitivity when shooting in 30p?
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Old April 26th, 2008, 07:59 PM   #2
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You'll need to slow down your pans. The speed of the pan can make your image fall apart between a certain range. Over it is fine as the streaks it makes are artistic and expected, below and the subject moves slowly enough within the frame that the brain compensates for the changes. There's a range in the middle that the brain can't deal with and it breaks the magic that is cinema.

In the ASC's manual for cinematographers, there are charts for panning speeds. These make it easy for DoP's to figure out how fast you can turn the lens at a given focal length and frame rate to make the image not break. The pretty and silky-smooth images you see in movies have a lot of physics behind them, it's kind of mind-boggling!
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Old April 29th, 2008, 01:42 PM   #3
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I worried about this as I was told the 30p would be great for fast action sports. I'm assuming 60p is what I'm looking for in a camera instead of the 30p. Any thoughts? Would 30p look good with fast moving objects?
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Old April 29th, 2008, 02:52 PM   #4
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Originally Posted by Todd Moen View Post
I worried about this as I was told the 30p would be great for fast action sports. I'm assuming 60p is what I'm looking for in a camera instead of the 30p. Any thoughts? Would 30p look good with fast moving objects?
ALL low frame-rate video is poor at capturing motion. 24p/25p/30p all suffer from "judder" from sampling at long intervals. Yes -- you want 60p!

25p/30p all suffer from strobing from the "eye tracking artifact" that is always seen by the eye+brain whenever the same image is presented twice. This always occurs when 25p/30p are viewed on a flat-panel running at 50Hz/60Hz.

What you describe as choppiness I might call strobing. You'll see motion as a series of jerks. It looks nothing like film. But, used carefully, it can look like "not video" which some may want.

24p has minimal strobing because projectors use 3-bladed shutters, but has two additional kinds of judder:

1) When 3-2 pulldown is added for recording, "mixed" frames are created. These are often called judder frames. Not a good name.

2) When 3-2 pulldown is added AS IT MUST BE for display on most all video displays -- the 3-2 cadence creates an visual pattern also called judder.

ONLY when either true 24p or 60i/24p has it's pulldown removed AND the output goes to film that is projected, will you not see these two types of judder. (You will see only the 24p judder that you see in all film.)

The key for EX1 users to know is that both strobing and judder is a much bigger problem with "prosumer" camcorders than with high-end CineAlta and Varicam units. In fact, these expensive camcorders AND lenses keep strobing and judder to almost the same low level as film. That creates a greater shooting challenge for EX1 shooters.

PS: If you record 24p to BD and play it on a player that feeds 24p to a display that runs at 72Hz can you eliminate these 2 types of judder. This is not a common setup -- and has its own problems.
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Old April 29th, 2008, 06:20 PM   #5
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Awesome reply Steve,
I'm wondering how you would set up the Z7 to shoot a not judder looking image. Fast action motion. Smooth flowing video. Is it possible?
Or am I just kidding myself and should look to the EX1...
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Old April 29th, 2008, 11:46 PM   #6
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Originally Posted by Todd Moen View Post
Awesome reply Steve,
I'm wondering how you would set up the Z7 to shoot a not judder looking image. Fast action motion. Smooth flowing video. Is it possible?
Or am I just kidding myself and should look to the EX1...
The answer is EZ -- jut shoot 1080i60i. But, of course, it's not that simple.

IF you want progressive video then you have 2 choices:

1) get an EX1 and shoot 720p60

2) Use a software app to convert 1920x1080i60 to 1280x720p60.

I documented this procedure for the JVC HD7 so it could be used as a B camera with other JVC 720p60 camcorder.

Do you need progressive video for some reason?
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Old April 30th, 2008, 12:43 PM   #7
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I don't, but its a feature that my FX-1 didn't have. I thought I would give it a try. I'm a wedding videographer, so nothing fast really gets going until the reception. I just thought it would be a better quality picture.
I will be burning some stuff to Blu Ray. I think I will just shoot 60i and let the Blu Ray players and HDTV's handle it from there.
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Old April 30th, 2008, 01:14 PM   #8
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I could be totally wrong here, but it seems I hear all the flat screens will be going progressive in the next year or so. From that, I was assuming I need to be shooting progressive to get the best look down the road. If I'm shooting interlaced frames, will that be fine for the progressive wide screens in the future? Is EX1 60p and the Z7 1080i60i equally as smooth?
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Old April 30th, 2008, 03:01 PM   #9
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Originally Posted by Todd Moen View Post
I could be totally wrong here, but it seems I hear all the flat screens will be going progressive in the next year or so. From that, I was assuming I need to be shooting progressive to get the best look down the road. If I'm shooting interlaced frames, will that be fine for the progressive wide screens in the future? Is EX1 60p and the Z7 1080i60i equally as smooth?
All flat screens are progressive. They deinterlace in the unit.

There's no problem shooting 1080i.
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Old May 5th, 2008, 12:21 AM   #10
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wow Steve, you just keep hitting the nail on the head & I can't say any of it better.

Chad, another big issue could be your shutter rate. the shorter the exposure (ie 1/1000 of a sec) less blur (good for freeze-framing action) but more 'judder.' the longer the exposure (ie 1/60 of a sec) the more blur & less 'judder'

so try slowing down the shutter speed & see if that helps out.

if you have more questions / concerns about shooting progressive feel free to look outside of the Z7 forums as this isn't a camera specific issue. there is lots of info out there on how to make 24p not look bad

& like Steve said before, if you're not sure about 1080p30 or 1080p24, then just shoot 1080i60 & shoot like how you're used to shooting
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