shutter speeds and slow mo

[Vince Manganello]

I'm using an XL-1s and editing on FCP and looking for some good slow motion, my question is: First of all, does anybody have experience with slow mo with these tools, especially if you have something I could see? Also, how will altering the shutter speeds effect slow mo. Would a higher speed make a less blurry shot? Any tips would be great, or point me to a thread/site that explains this. Thanks.

[Adam Lawrence]

theres a program called Reelsmart Twixtor... its available for FCP.

http://www.lafcpug.org/review_twixtor.html

Ive used it for AE and it works pretty well....it makes the footage look like
its actullay shot with a higher frame rate to create real slow motion.

Using a higher shutter speed will sharpen the footage when slowed down..
therefore you have no motion blur, that way every frame would be clear to slowdown in post

[David Bogie]

Twixtor is a valid hack but it's still a hack. It creates pixels by interpolating between frames. Incredibly cool. And expensive. And very render intensive.

Slow motion is achieved by shooting more frames in a given time unit than can be played back. On film, shooting 48 frames per second and playing it back at 24fps produces a smooth slow motion because twice as many frames were used to capture the real time action.
In video, you have only 30fps unless you are renting special high frame rate-density equipment. I think Sony still makes the only 90fps units that are used in sports event coverage. There are more interesting systems that will go up to several thousand frames per second but they capture directly to computer memory and are non-standard formats that must be converted. Boy, are they cool.

Double your video clip's length with time remapping and all you get is the same frame printed twice. Add some frame blending (and the tremendous rendering hit it requires) and you can get some nice smooth playback but you still only have 30 discreet slices of time for every second of captured action. Twixtor can create more discreet slices of time for you at tremendous cost.

If your need for slow motion is critical, you must use slow motion acquisition. You cannot depend on being able to fake it in post. Shoot on film or get special video gear.

Shutter speed is directly related to image sharpness. Shutter speed has nothing to do with slow motion at all except as a creative control. It is far easier to blur an image or extend trails in post than it is to attempt to sharpen an image so go for clrity in the camera.

david

[Nerses Papoyan]

Guys, I have a question, when you see for example Pizza Hut TV Commercial, and the pizza spining very fast then it slows down spining very slow showing the pizza, how do they do that? I have XL h1, and have ability to record in 60Fps, should I use 60 ? 30 or 24 fps to get that effect?
I'm editing in Premiere Pro 2.0 and After Effects 7.0

Any tips, about shutter speed, and frame rate, to achive best slow motion to show food spining, another example you can see in Burger commercials, burger sinning very fast for a sec, then slows down really slow motion , but the picture is excelent.

Thank you in advance

[Dave Perry]

Originally Posted by Nerses Papoyan

Guys, I have a question, when you see for example Pizza Hut TV Commercial, and the pizza spining very fast then it slows down spining very slow showing the pizza, how do they do that? I have XL h1, and have ability to record in 60Fps, should I use 60 ? 30 or 24 fps to get that effect?
I'm editing in Premiere Pro 2.0 and After Effects 7.0

The XL H1 shoots 60 FIELDS per second interlaced which equals 30 FRAMES per second. Two fields make up one frame of interlaced footage. That's what "60i" refers to. You aren't shooting 60 frames per secomd.

[Matt Throop]

So I guessing from the responses. I can't create a good fluid slow mo segment for a music video then with the XL-2. I just don't want the motion blur in the video. Any ideas on how create nice fluid slow mo?

[Glenn Chan]

Shoot 60i, slow it down to 24p or 30p. Start from there.
When people say 60i, they mean 60 fields per second (or actually 59.94).
Map each field to a frame, and you'd get slow motion.

Beyond that, you can use Shake (very cheap now) or plug-ins like Twixtor to do optical flow image processing... it's a better slowmo technique than simple blending fields (i.e. what FCP does).

Optical flow is generally extremely slow. Depending on the subject, you can slow things down by up to 10X (further) or less. Things that have simple motion will work best... smoke, liquids, etc. won't slow down well.

What David is saying is that Twixtor (and similar techniques) are 'faking the funk', since they try to create information that doesn't exist. It generally looks quite seamless, although complex motion will cause weird artifacts that aren't seamless.

- The shutter speed will affect how much motion blur you get, which will interact with how your slow mo with look (and how well the algorithm can guess the motion).

[Cole McDonald]

We're duscussing this over here:

http://www.dvinfo.net/conf/showthread.php?t=68425

[Matt Throop]

Thanks, Glenn, and Cole. Muchly apprecaited.