GH3 Please help me understand Slo Mo on the GH3

I

Ianscreations

Well-known member
Can someone please help me understand Slow Motion on the GH3 and the workflow to achieve the best results?

For example, why is 60fps needed for slow motion? Does it just achieve a smoother look? I assume to achieve proper slo mo in post, you shoot in 60fps and edit in a timeline of 30fps, slowing the footage down by 50%?

What is the difference between doing this and just choosing the 40% frame rate within the camera?

Thanks for your help understand thing.
 
The camera can either shoot natively up to 60fps with sound just as it does with 24/25/30p or it can do a clip in native 24/25p with the footage at -40% to +300% without sound.

I would look upon the 60fps mode if you need to have smoother fast motion at normal speed and the -40% to +300% if you want to do real slowmotion.
 
You don't get sound, but it technically it shoots at 60fps then automatically converts it 40% (24fps). Make sure you set your shutter speed to 1/125 for accurate motion blur.
 
So are there any disadvantages to shooting at 60p and then editing that in a 24fps timeline - to record sound as well in the event you need it?
 
No - in fact, if you have the right editing suite, that's probably the better way to go. Just a little more labor intensive.
 
Osslund said:
The camera can either shoot natively up to 60fps with sound just as it does with 24/25/30p or it can do a clip in native 24/25p with the footage at -40% to +300% without sound.

I would look upon the 60fps mode if you need to have smoother fast motion at normal speed and the -40% to +300% if you want to do real slowmotion.
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I usually shoot at 30fps b/c I do a lot of event videography and 24fps has too much motion blur for what I want to achieve.
That being said, do you recommened not usng the camera's frame rate to achieve slow mo since it is effectively 24 fps?

For example, if I know I want something to be slow mo in post, but I am shooting at 30fps, should I switch to 60fps with a SS of 120?
 
If I knew something to be a slowmotion clip I would use the slowmotion embedded recording rather than 1080p60. Then I can play the clip in camera with slowmotion. It also has the advantage that when you edit slowmotion with your normal speed footage both shutter and framerate stays the same. Use 180 degrees shutter always and you are good unless it's green screen, then use 90 degree shutter.
 
Osslund said:
If I knew something to be a slowmotion clip I would use the slowmotion embedded recording rather than 1080p60. Then I can play the clip in camera with slowmotion. It also has the advantage that when you edit slowmotion with your normal speed footage both shutter and framerate stays the same. Use 180 degrees shutter always and you are good unless it's green screen, then use 90 degree shutter.
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You can do in camera slow motion even with the regular 1080p @ 60 FPS footage with sound. Just play the video and then hit pause. Then hold the right arrow button down. It will playback in extremely nice slow motion.

There is NEVER a reason to use the in-camera slow motion. It simply is never better than slowing down in post plus you always have the audio with the 1080p @ 60 FPS mode.
 
mpgxsvcd said:
There is NEVER a reason to use the in-camera slow motion. It simply is never better than slowing down in post plus you always have the audio with the 1080p @ 60 FPS mode.
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I subscribe to this method also. I don't like limiting my choices and sometimes like to smoothly ramp footage from normal motion to slow and need the sound. the 1080/60p is really nice on the GH3 and a welcome addition to me.
 
mpgxsvcd said:
There is NEVER a reason to use the in-camera slow motion.
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You've stated this before, & I debunked it then, but here we go again.

There are major advantages to shooting over/under-crank in-camera & for MY WORK it's the only way to roll. But I work with Sound Persons, & Editors, so this may not be appropriate for YOUR NEEDS.

One major advantage is the ability to check playback for strobing. This is huge! Your method plays back footage at an unknown framerate so useless for this task.

Another major advantage comes when handing off raw footage to Editors. They are instantly able to identify what footage is recorded at standard speed & which if off-speed. That is also huge, & saves valuable time in post.

Lastly by deciding to over/under crank when filming we're able to select the optimal shutter speed/angle for capturing the desired motion blur.
 
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Bern Caughey said:
Lastly by deciding to over/under crank when filming we're able to select the optimal shutter speed/angle for capturing the desired motion blur.
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Because you mention it: How do you set the shutter speed when using the GH3 percentage values?
When I shoot 50p, I know I will use 1/100 - or is shutter speed set automatically when using in-camera slomo?
 
Bern Caughey said:
You've stated this before, & I debunked it then, but here we go again.

There are major advantages to shooting over/under-crank in-camera & for MY WORK it's the only way to roll. But I work with Sound Persons, & Editors, so this may not be appropriate for YOUR NEEDS.

One major advantage is the ability to check playback for strobing. This is huge! Your method plays back footage at an unknown framerate so useless for this task.

Another major advantage comes when handing off raw footage to Editors. They are instantly able to identify what footage is recorded at standard speed & which if off-speed. That is also huge, & saves valuable time in post.

Lastly by deciding to over/under crank when filming we're able to select the optimal shutter speed/angle for capturing the desired motion blur.
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Fair enough. But you still lose out on a significant amount of leeway with the final slow-mo clip by choosing to do in-camera rather than 60P. In a NLE, I can slow a 60P clip down anywhere between 40% and 100% of the original speed and get a nice, smooth effect. With the in-camera mode, you have lost the additional frame information and are stuck with whatever speed you shot it at.

As for the editor flagging - proper clip labeling is a much better workflow approach than relying on the actual speed of the clip.

Let's face it - both approaches have their advantages and disadvantages. But for most users, 60P is a wiser and more flexible option than using in-camera slow-motion.
 
Bern Caughey said:
Another major advantage comes when handing off raw footage to Editors. They are instantly able to identify what footage is recorded at standard speed & which if off-speed. That is also huge, & saves valuable time in post.
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Professional editors should be able to spot immediately when material is 25p,50p,60p,60i or any other. If they don't check what material they get, they are amateurs. Good NLE's show the material's properties immediately, even while editing.
 
Bern Caughey said:
One major advantage is the ability to check playback for strobing. This is huge! Your method plays back footage at an unknown framerate so useless for this task.
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This is major. Glad you brought it to attention. I had a minor strobing issue on a short because of the wrong shutter angle. Very good point.

That being said though, When shooting under practical fluorescent lighting I think the best way would be to check the strobing with overcrank in camera then shoot the final scene at 60p to retain sound in needed.

I find motion blur not really an issue and if it becomes one it is possible to insert more with AE
 
Another thing to look at when choosing to record slow motion with either 40% in camera or using 60p mode and slowing it down in post is the the overall codec quality.

In AVCHD mode in camera 40% records at an overall bit rate of 24.0 Mbps - High @L4.0 profile, while 60p mode records at an overall bit rate of 28.0 Mbps - High @L4.2 profile.

In MP4 mode in camera 40% records at an overall bit rate of 22.9 Mbps - High @L4.1 profile, while 60p mode records at an overall bit rate of 29.0 Mbps - High @L4.2.

In MOV mode in camera 40% records at records at an overall bit rate of 23.7 Mpbs - High @L4.1 profile, while 60p mode uses records at an overallbite rate of 72.5 Mbps - high @ L5.0

MP4 and MOV offer higher bit rates compared to AVCHD but it reveals more noise from the sensor. AVCHD in 60p mode is the cleanest in terms of noise and offers slightly better quality over using AVCHD 40% mode.
 
rigs said:
Another thing to look at when choosing to record slow motion with either 40% in camera or using 60p mode and slowing it down in post is the the overall codec quality.

In AVCHD mode in camera 40% records at an overall bit rate of 24.0 Mbps - High @L4.0 profile, while 60p mode records at an overall bit rate of 28.0 Mbps - High @L4.2 profile.

In MP4 mode in camera 40% records at an overall bit rate of 22.9 Mbps - High @L4.1 profile, while 60p mode records at an overall bit rate of 29.0 Mbps - High @L4.2.

In MOV mode in camera 40% records at records at an overall bit rate of 23.7 Mpbs - High @L4.1 profile, while 60p mode uses records at an overallbite rate of 72.5 Mbps - high @ L5.0

MP4 and MOV offer higher bit rates compared to AVCHD but it reveals more noise from the sensor. AVCHD in 60p mode is the cleanest in terms of noise and offers slightly better quality over using AVCHD 40% mode.
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1080 60fps on MOV might show more noise, but the beautiful bit rate allows for better post processing. Personally I can live with a little noise and use a denoiser. Great information though and something people should be aware of.

On a side note I really Love the GH3, mine is currently out of the country being fixed and can't wait to get it back!
 
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