GH4 GH5 180FPS Workflow Question

[Ianscreations]

This is the first camera I have ever used/owned that allows 180fps shooting and I have been super excited about that.
Today I filmed my son and his friend sprinting up the sidewalk as a test and the footage looks great in camera. I had the lens wide open at f1.8 and jacked up shutter speed to make sure I was well beyond the 180 degree rule.

In camera, the footage looks fantastic on playback. But I am struggling with the workflow in post.

When I import the clip into Premiere, it recognizes the clip at 60fps.
When I place the clip on a 24fps timeline it plays back nicely at a reduced speed, but I can't tell by how much. If I try to reduce the speed of the clip by more than 30%, it starts to get pretty jumpy and no longer has smooth motion.

What is the proper editing workflow that allows me to slow this clip down as much as possible without frame drops or with a smooth playback?

 

[-griffy-]

If it's showing up as 60fps, that means you turned on VFR for a 1080p 60fps format on the GH5. The camera will automatically conform the footage to the framerate of the mode you turn VFR on for. So if you want it to be 24fps, you need to turn on VFR when you are in a 24fps format. Then the clip will just be conformed to a normal 24fps and you can drop it into a 24fps timeline and it will behave normally. You don't have to do any additional tweaking.

If you want to get the most out of the 60fps footage you already have without it getting choppy, then right click on it in the project window, select "Interpret Footage" and set the framerate to 23.976/24 (whatever your timeline is).

 

[filmguy123]

What was your rec quality set to? FHD 60p, 30p, or 24p?

Sounds like FHD 60p which is your BASE frame rate. This means all clips will play back at 60fps regardless of how much it was overcranked. So, a 180p clip would represent a 3x overcrank/slow down (33% speed slow motion). If you used a base time of 24p, your effective slow motion rate would be much slower - about 15%.

So yes, Premiere should recognize the clip at 59.97 (60p) and that is CORRECT. If it was shot on a 24p base, Premiere should also recognize it as such. Your editing software knows nothing of what VFR rate you shot it at, and it doesn't need to. VFR conversion happens IN-CAMERA. Those 180 frames you shot are now displayed and saved as 60 frames a second, so that every second you were filming is recorded as 3 seconds in camera and will import to premiere as 3 seconds of 60p footage. It will already looked slow down in editing, because it was recorded that way.

DO NOT slow down VFR footage in post. That is artificially adding frames in software which is very different than overcranking and can create a juttery effect, because at 30% speed in software you are basically artificially holding every single frame 3x as long - not creating new frames (for that, you need special software plugin such as Twixtor).

If you want to shoot cinematic looking slow motion, set your in camera capture rate to FHD 24p, choose your VFR mode in camera, shoot, import, and then edit the clips as they are. They are already accurate in their display of time.

Regarding cranking your shutter rate well past the 180 degree rule to be safe, I think you misunderstand the 180 degree rule. That is not a safety net to give yourself extra margin on - anything in either direction is a creative choice at fundamentally changes the motion blur properties. Leave it at 180 for proper cinematic motion blur. Also, when you say you increased the shutter, do you mean you moved it upwards toward 240 degrees? Or downward toward 120? Making your shutter angle smaller, say 120, will give you sharper and crisper motion (less motion blur) but moving it upwards toward 240 will increase your motion blur and make things potentially too blurry.

There is nothing inherently wrong with changing your shutter angle, but it's not a matter of giving the camera extra safety margin, it's a specific creative decision. Increasing shutter speed (which is a decrease in shutter angle) can give you the gladiator effect, but if you don't want that, can give an odd juddery appearance to motion.

 

[Ianscreations]

Griffy and Filmguy....excellent feedback. Thank you for all the helpful information! I'll have my son run again today. LOL. He walked up and down the sidewalk about 20 times yesterday testing the various autofocus settings that work well for situations where I will use it. He's a patient one.