Slow motion according to barry green

T

thome

Well-known member
hey,
i found a thread where Barry said

For the PAL/EU/AUS/NZ cam, set the recording mode to 720/25pN, then set your frame rate to whichever your chosen fps is. Then adjust the speed of the song according to this table:

12 fps: make song last 2.000x as long as normal; play it at 50.00% speed
18 fps: make song last 1.400x as long as normal; play it at 71.44% speed
20 fps: make song last 1.266x as long as normal; play it at 78.96% speed
23 fps: make song last 1.080x as long as normal; play it at 92.60% speed
27 fps: make song last 0.920x as long as normal; play it at 108.68% speed
30 fps: make song last 0.840x as long as normal; play it at 119.04% speed
32 fps: make song last 0.778x as long as normal; play it at 128.56% speed
37 fps: make song last 0.680x as long as normal; play it at 147.04% speed
48 fps: make song last 0.520x as long as normal; play it at 192.32% speed
50 fps: make song last 0.500x as long as normal; play it at 200.00% speed



1.So what about in the dvx?if i shoot at 50i then use a shutter speed of say 1/120 will i still use this

50 fps: make song last 0.500x as long as normal; play it at 200.00% speed

or will it be different because on the HVX the setting is 720/25pN???
Sorry if this is an obvious question...just need to understand.

2.What happens if you want to shoot slow motion then fast motion like what they do in a movie like matrix?where when a someone throws a punch,its silky slow then it suddenly goes really fast..will you shoot the same scene in two different frame rates?and how will that blend in post?especially in sony vegas?



HELP
 
thome said:
1.So what about in the dvx?if i shoot at 50i then use a shutter speed of say 1/120 will i still use this

50 fps: make song last 0.500x as long as normal; play it at 200.00% speed

or will it be different because on the HVX the setting is 720/25pN???
Sorry if this is an obvious question...just need to understand.
Click to expand...

That chart from Barry is for cameras that can over/undercrank, which means that they can shoot at higher or lower frame rates. The DVX cannot do this. Since you're working with PAL, you are stuck with 25p, 30p, or 50i.

The best you can do is either to:

- shoot at 30p and then conform it to 25p (if this is for a music video, you're looking at approximately 83% - 83.333 to be exact - playback speed of the final video); or

- shoot at 50i and use something like Twixtor to pull out a 25p signal, effectively giving you a half-speed playback.

thome said:
2.What happens if you want to shoot slow motion then fast motion like what they do in a movie like matrix?where when a someone throws a punch,its silky slow then it suddenly goes really fast..will you shoot the same scene in two different frame rates?and how will that blend in post?especially in sony vegas?
Click to expand...

It's called time remap, and it is usually accomplished with one continuous shot. Essentially, the scene is shot in overcrank so that the slow-mo portions are smooth. Time remap changes the playback speed of the clip over time. But again, the DVX can't overcrank, which means that you won't get silky-smooth slow-mo.
 
Thanx alot C2v

- shoot at 30p and then conform it to 25p (if this is for a music video, you're looking at approximately 83% - 83.333 to be exact - playback speed of the final video)
How did you come up with 83.333?whats the calculation?

Think its time to jump to a hvx so that i can get more options
 
thome said:
How did you come up with 83.333?
Click to expand...

At 25fps, one frame = 1/25 of a second. At 30fps, 1 frame = 1/30 of a second. When you conform a 30p clip to 25p, it doesn't add or delete frames, but adjusts the playback time of each frame, meaning that it stretches the playback time out and makes the source video play slower.

25/30 = 5/6 = 83.333%.
 
you can shoot 50 for 25 with a pal DVX
Difference is you conform the 50 to 25 in post (with cinema tools if you are on a mac).
This is the best way to get slow motion as opposed to a software solution.

EDIT: see you said basically said that C2V. Skimmed your 1st post, thought you were saying there was no way initially.
 
Thanx....so i shoot 50i at 1/120 shutter speed then then the playbak at 50%?is that right?
 
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