Slow motion in camera vs. post

Phil Bloom · December 28th, 2007, 03:43 AM

It means the best years of your life are over

Stelios Christofides · December 28th, 2007, 03:46 AM

Quote:

Originally Posted by Phil Bloom

It means the best years of your life are over

Phil, Thanks for the quick reply, but if the guy in the video is you, then the best years are still to come.

Stelios

Phil Bloom · December 28th, 2007, 03:50 AM

ha ha! its not me...would have been hard to film. its my dad. he is just the actor but i will forward him the comment! he will like that!

Ray Bell · December 28th, 2007, 09:15 AM

Quote:

Originally Posted by Phil Bloom

twixtor is great but the biggest problem with it is the long render times and the lack of preview.

Phil, Would you recomend the standard version of Twixtor or the Pro version....

I have been wanting this plug in for a while now...

Thanx....

Also, do you use the fields kit deinterlacer with twixtor???

Stelios Christofides · December 28th, 2007, 09:50 AM

Quote:

Originally Posted by Phil Bloom

ha ha! its not me...would have been hard to film. its my dad. he is just the actor but i will forward him the comment! he will like that!

Phil please tell your dad this true story:

Once they asked Zorba the Greek, why he is always vibrant and happy and enjoy life so much. He then told them this: " When I wake up is like everyday is the last and like everyday is the first day in my life at the same time".
Get your dad the book " Zorba the Greek" He will thoroughly enjoy it.

Stelios

P.S. here is another thing from Zorba
"God always forgive everything wrong we did in our lives. But He never forgives a man if a woman desires him and this man doesn't offer her the satisfaction she needs. This is the only thing according to Zorbas that God doesn't forgive to men..."

Phil Bloom · December 28th, 2007, 04:18 PM

Quote:

Originally Posted by Ray Bell

Phil, Would you recomend the standard version of Twixtor or the Pro version....

I have been wanting this plug in for a while now...

Thanx....

Also, do you use the fields kit deinterlacer with twixtor???

i dont have the pro version or know about the deinterlacer

Mike Barber · December 31st, 2007, 04:39 PM

I have never played with a camera that can do any variable speeds, so I am completely in the dark about this (and the resulting workflow in the editing room). So the only slomo (or fastmo) I have ever done has been done from the timeline (in my case FCP). I understand the principals of why slow motion done in camera (film) has a different look than slow motion done from the timeline (in camera = object appears to be "moving through a denser medium than air", as Herb Zettl puts it; in post = time slows down). What I am curious to know, is the over/under cranking features of the EX1 analogous to that of film cameras? Do you get the same frame density and seemingly absence of gravity that film overcranking gives us?

Also, what would the workflow be from shoot to post?

Bernard Racelis · December 31st, 2007, 10:40 PM

I played around with the slow motion in-camera and I confirm what Eric described.

Example (1) - Record at normal speed 30p (720p30)

The file size for 1 second = 5MB.

1 second realtime = 1 second in the Editor timeline/playback:

Code:

            
|        30 frames   |
|------------------->|                        (Editor Timeline)
                  00:01

Example (2) - Record at 60 frames over 30p (slow motion in-camera)

1 second realtime becomes 2 seconds in the Editor timeline/playback:

Code:

|        30 frames   |   30 frames       |
|------------------->|------------------>|     (Editor Timeline)
                   00:01              00:02

* The file size is doubled (the camera recorded twice the normal bitrate -- 35Mb/sec times two)

10 MB = 1 second realtime = 2 seconds in the editor timeline/playback.

Therefore, each second in the timeline/playback is still 5MB (35Mb/sec).

Example (3) - Record at native 60p

Drop the 1 second clip on a 30p editor timeline,
and stretch it to 2 seconds (slow down 50%) in the Editor timeline:

Code:

|         30 frames  |   30 frames       |
|------------------->|------------------>|        (Editor timeline)
                   00:01              00:02

* File size = 5MB (Although native 720p60 has double the framerate of native 720p30, they're both recorded at the same 35Mb/sec bitrate.)

Because 5MB of video is streched in the timeline, there is now only half (2.5MB) of data per second (bit rate is halved).

Eric Pascarelli · January 1st, 2008, 12:20 AM

Bernard,

Very well explained.

Mike,

Yes, it would be virtually identical. There are many samples of the 60 frame overcrank on these forums (and linked from this forum). Phil Bloom has some lovely examples on his blog.

The only thing to mind is your shutter speed. If you keep it in "angle" mode and set to 180° then you will have a very convincing film cadence.

Workflow is seamless because, when you overcrank or undercrank in camera, the camera still tags the file at a predetermined *playback* speed. Just drop it in the timeline and you are done.

So if you are in 24p mode, those clips will play back at that rate in the timeline regardless of how you over or undercranked them while shooting - and this is exactly how film behaves.

When you speed up or slow down in post (assuming you do it as a simple speed change and do not use Twixtor or Kronos or something like that) you will see a change in playback frame rate. 24 sped up to 60 in post looks fast motion but also takes on a "video" look because the screen is updating at 60 frames (or fields) per second. It gets a more present "live" look that does not cut well with other footage. Or, if you drop frames (because your timeline does not display 60fps) you get a strobier look. When you slow down in post you start to see a choppiness because you are repeating frames to fill the time.

There are many plugins that alleviate the above mentioned choppiness or strobiness (they are described earlier in this thread) that do "in betweening" and redraw th motion blur to remove the appearance of choppiness. The plugins track the movement of each pixel and synthesize frames where there are none. They work great for smaller speed changes, but start to show their limitations for larger changes. They are easily fooled by random motion (fire, water) and objects appearing and disappearing (moving behind one another). They also start to get confused by compressed footage with lower color sampling (like DV or HDV - haven't done much testing with XDCAM).

By far the best software for this is Kronos by The Foundry (who have uniquely solved many of the pitfalls associated with this process). Expensive, but amazing results.

With this software, post speed changes can approach the look of in camera speed changes. But still the best way to do it to maintain the look we all associate with "high quality" is to do it in-camera. And the EX1 does this very well.

Mike Barber · January 1st, 2008, 03:22 AM

Quote:

Originally Posted by Eric Pascarelli

Yes, it would be virtually identical. There are many samples of the 60 frame overcrank on these forums (and linked from this forum). Phil Bloom has some lovely examples on his blog.

The only thing to mind is your shutter speed. If you keep it in "angle" mode and set to 180° then you will have a very convincing film cadence.

Workflow is seamless because, when you overcrank or undercrank in camera, the camera still tags the file at a predetermined *playback* speed. Just drop it in the timeline and you are done.

So if you are in 24p mode, those clips will play back at that rate in the timeline regardless of how you over or undercranked them while shooting - and this is exactly how film behaves.

Many thanks for the reply Eric. I don't know anything about altering the shutter axis, but it is good to know I should be mindful of that detail.

So I guess the only bugger about the overcranking feature is that the EX1 only does 1-30fps in 1080p (while doing 1-60fps in 720p). Overcranking options whilst shooting in 720p are great, but for 1080p the limit is 30fps, which would only allow one to "reduce" the apparent speed of the action (in camera) to -- uh, I can't even begin to try to do the math on this one -- 80%, is that correct? (My math skills are embarrassingly horrible.)

I guess this posses the filmmaker with a choice between: a) shooting in a resolution that is ideal to film outs, but with limitations on in-camera slo-mo; and b) having greater in-camera slo-mo options, however shooting at a smaller resolution and having to blow your image up for film out. Is that right?

Ray Bell · January 1st, 2008, 08:57 AM

Another option for 1080 is to shoot at 60i and convert the footage to 60P
in post....

no other way to get 1080p60 with this camera...

One software plugin to help with this is Fieldskit

Steven Thomas · January 2nd, 2008, 10:55 AM

Quote:

Originally Posted by Ray Bell

Another option for 1080 is to shoot at 60i and convert the footage to 60P
in post....

That's not a bad idea for those who want to stay in 1080P.

Eric Pascarelli · January 2nd, 2008, 05:28 PM

But it effectively halves your vertical resolution and adds some vertical jitter in the process. I would prefer up-resing 720p - I think in the end it will look better. Haven't tested it with this camera but I have seen the results with other HD cameras.

December 28th, 2007, 03:43 AM	#16
Phil Bloom Trustee Join Date: Aug 2006 Location: London UK Posts: 1,939	It means the best years of your life are over __________________ Philip Bloom Cinematographer, Director, Filmmaker www.philipbloom.net

December 28th, 2007, 03:50 AM	#18
Phil Bloom Trustee Join Date: Aug 2006 Location: London UK Posts: 1,939	ha ha! its not me...would have been hard to film. its my dad. he is just the actor but i will forward him the comment! he will like that! __________________ Philip Bloom Cinematographer, Director, Filmmaker www.philipbloom.net

December 31st, 2007, 04:39 PM	#22
Mike Barber Major Player Join Date: May 2006 Location: Toronto ON Canada Posts: 731	video overcranking identical to film overcranking? I have never played with a camera that can do any variable speeds, so I am completely in the dark about this (and the resulting workflow in the editing room). So the only slomo (or fastmo) I have ever done has been done from the timeline (in my case FCP). I understand the principals of why slow motion done in camera (film) has a different look than slow motion done from the timeline (in camera = object appears to be "moving through a denser medium than air", as Herb Zettl puts it; in post = time slows down). What I am curious to know, is the over/under cranking features of the EX1 analogous to that of film cameras? Do you get the same frame density and seemingly absence of gravity that film overcranking gives us? Also, what would the workflow be from shoot to post? __________________ Mike Barber "I'm laughing to stop myself from screaming."

December 31st, 2007, 10:40 PM	#23
Bernard Racelis Regular Crew Join Date: Dec 2007 Location: New York City Posts: 82	I played around with the slow motion in-camera and I confirm what Eric described. Example (1) - Record at normal speed 30p (720p30) The file size for 1 second = 5MB. 1 second realtime = 1 second in the Editor timeline/playback: Code: \| 30 frames \| \|------------------->\| (Editor Timeline) 00:01 Example (2) - Record at 60 frames over 30p (slow motion in-camera) 1 second realtime becomes 2 seconds in the Editor timeline/playback: Code: \| 30 frames \| 30 frames \| \|------------------->\|------------------>\| (Editor Timeline) 00:01 00:02 * The file size is doubled (the camera recorded twice the normal bitrate -- 35Mb/sec times two) 10 MB = 1 second realtime = 2 seconds in the editor timeline/playback. Therefore, each second in the timeline/playback is still 5MB (35Mb/sec). Example (3) - Record at native 60p Drop the 1 second clip on a 30p editor timeline, and stretch it to 2 seconds (slow down 50%) in the Editor timeline: Code: \| 30 frames \| 30 frames \| \|------------------->\|------------------>\| (Editor timeline) 00:01 00:02 * File size = 5MB (Although native 720p60 has double the framerate of native 720p30, they're both recorded at the same 35Mb/sec bitrate.) Because 5MB of video is streched in the timeline, there is now only half (2.5MB) of data per second (bit rate is halved).

January 1st, 2008, 08:57 AM	#26
Ray Bell Regular Crew Join Date: Nov 2004 Posts: 1,414	Another option for 1080 is to shoot at 60i and convert the footage to 60P in post.... no other way to get 1080p60 with this camera... One software plugin to help with this is Fieldskit Last edited by Ray Bell; January 1st, 2008 at 01:46 PM.

January 1st, 2008, 12:20 AM	#24
Eric Pascarelli Major Player Join Date: Nov 2007 Location: Los Angeles, CA Posts: 498	Bernard, Very well explained. Mike, Yes, it would be virtually identical. There are many samples of the 60 frame overcrank on these forums (and linked from this forum). Phil Bloom has some lovely examples on his blog. The only thing to mind is your shutter speed. If you keep it in "angle" mode and set to 180° then you will have a very convincing film cadence. Workflow is seamless because, when you overcrank or undercrank in camera, the camera still tags the file at a predetermined playback speed. Just drop it in the timeline and you are done. So if you are in 24p mode, those clips will play back at that rate in the timeline regardless of how you over or undercranked them while shooting - and this is exactly how film behaves. When you speed up or slow down in post (assuming you do it as a simple speed change and do not use Twixtor or Kronos or something like that) you will see a change in playback frame rate. 24 sped up to 60 in post looks fast motion but also takes on a "video" look because the screen is updating at 60 frames (or fields) per second. It gets a more present "live" look that does not cut well with other footage. Or, if you drop frames (because your timeline does not display 60fps) you get a strobier look. When you slow down in post you start to see a choppiness because you are repeating frames to fill the time. There are many plugins that alleviate the above mentioned choppiness or strobiness (they are described earlier in this thread) that do "in betweening" and redraw th motion blur to remove the appearance of choppiness. The plugins track the movement of each pixel and synthesize frames where there are none. They work great for smaller speed changes, but start to show their limitations for larger changes. They are easily fooled by random motion (fire, water) and objects appearing and disappearing (moving behind one another). They also start to get confused by compressed footage with lower color sampling (like DV or HDV - haven't done much testing with XDCAM). By far the best software for this is Kronos by The Foundry (who have uniquely solved many of the pitfalls associated with this process). Expensive, but amazing results. With this software, post speed changes can approach the look of in camera speed changes. But still the best way to do it to maintain the look we all associate with "high quality" is to do it in-camera. And the EX1 does this very well.

January 2nd, 2008, 05:28 PM	#28
Eric Pascarelli Major Player Join Date: Nov 2007 Location: Los Angeles, CA Posts: 498	But it effectively halves your vertical resolution and adds some vertical jitter in the process. I would prefer up-resing 720p - I think in the end it will look better. Haven't tested it with this camera but I have seen the results with other HD cameras.