Shooting in 24fps Vs Exporting to 24fps? (Also high frame rate related 120)

[BamBamBigelow]

Hi,

I am relatively new to video editing and so if I have said anything that doesn't make sense or that isn't correct, then please forgive my inexperience.

I want to shoot some video content in 24fps. However. I am concerned that should I shoot at this frame rate I may lose the opportunity to capture something spare of the moment at a higher frame rate such as 120fps that would look effective in slow motion.

I understand that in post, it is possible to export a video to a lower frame rate but I imagine a problem with that is the editing software is going to have to choose which 96fps (120 - 24) to lose and this could cause quality issues.

Any suggestions?


Kind Regards,

BBB

[manono]

but I imagine a problem with that is the editing software is going to have to choose which 96fps (120 - 24) to lose and this could cause quality issues.

It won't choose anything but delete them in a constant and repeating pattern:
1xxxx2xxxx3xxxx4...


But that's not how you make a slow motion video anyway. You just slow it from 120fps to 24fps. No frames are deleted unless you do another sort of slowdown.

[BamBamBigelow]

So are there any benefits to shooting in 24fps as apposed to 120fps? Or is it irrelevant whether you shoot in 120fps and slow it down to 24fps?

Thanks for the help

BBB

[jagabo]

You can decimate by every N'th frame, keeping the running time. So:

120/2 = 60
120/3 = 40
120/4 = 30
120/5 = 24
120/6 = 20
etc.

What you lose at high frame rates is motion blur. This can be somewhat alleviated in software. Without motion blur you will get flickery video at 24 fps.

The shorter exposure time required to shoot at 120 fps leads more noise in the images.

[newpball]

I want to shoot some video content in 24fps. However. I am concerned that should I shoot at this frame rate I may lose the opportunity to capture something spare of the moment at a higher frame rate such as 120fps that would look effective in slow motion.

Then the first question you should ask yourself why 24fps?

Why not consider 50p/60p instead? (and completely stay away from interlaced, it is a pest).

Also if you have scenes you know you want to show in slow motion record them at a higher framerate and then render them with a lower framerate.

[BamBamBigelow]

A lot of my shooting will be off the cuff spare of the moment . I will have the settings already set up so that this spontaneity can be filmed and will be changed throughout the day at regular intervals for changes in the environment such as lighting.

120 fps isn't essential and just a hypothetical example of a higher frame rate. So 50/60p is fine.

As you may have fathomed. My preference for 24fps is the 'filmic' look. The majority of the content will be ran in 'real' time with the odd shot here and there in slow motion to extenuate a certain shot. Problem is. I aren't going to always know said shot until post.

Again. If anything I said sounds out of place or wrong then please excuse the lack of knowledge.

I thank you all for your help. You're filling the void.

BBB

[poisondeathray]

Also, consumer level cameras that shoot 120FPS usually have lower effective resolution or lower quality at that framerate, or bandwith issues compared to the lower fps modes. Often in camera processing isn't fast enough, and they subsample the sensor, or the bandwidth is too low and the recording quality is low. You need more expensive camera models and external recorders to do it properly

[newpball]

As you may have fathomed. My preference for 24fps is the 'filmic' look.

May I ask what camera do you think is going to give you this filmic look because I fear you are setting yourself up for delusion and/or disappointment?

[sophisticles]

Granted I am not a professional but I would shoot at 24fps or possibly 48fps.

The thing to remember is that the higher the frame rate you are shooting at, the lower the per frame quality will be at any given bit rate, all other things being equal.

What kind of camera and lens will you be shooting at?

The important thing to remember is that the slow mo effects you see in movies are not done in one take in real time, it's a combination of shots, that are edited separately and then combined in software and rendered out as one movie.

[BamBamBigelow]

Just a bit of background so it doesn't sound like someone who throws money at something whimsically. I am a photographer and have a degree in photography but it is only recently where I have also discovered an interest and engaged in video. The artistic side of video has many cross overs to photography and as such it is easier to bridge that gap, with there being similarities in the fundamental principles.

Admittedly. When it comes to the technical side of video I am found wanting. So I am paying some due diligence and doing the research.

Cameras available for me to use - Sony RX100 mkIII - Lumix ZH100 - Lumix GH4


Correct me if I am wrong but I was under the impression that 24fps was an agreed compromise between image quality and film usage. With 24fps being the slowest it could be acceptably played at. 24fps then goes on to largely be the industry standard and the aesthetic becomes rooted in our subconscious and conscious. 24fps also having a good divisibility. This is the kind of aesthetic I am trying to emulate.

BBB

[newpball]

Lumix GH4

That is a pretty decent camera especially if you decide to capture with an external device!

J
Correct me if I am wrong but I was under the impression that 24fps was an agreed compromise between image quality and film usage.

Nope, 24fps come from the fact that 18fps could not carry sound well enough, the minimum was 24fps.

[poisondeathray]

Well that explains the mindset. In photography, some of the best award winning shots are spur of the moment, "right time, right place" almost "lucky"

In contrast, in cinematography (theatrical, dramas) nothing is spur of the moment. Everything is scripted, planned well in advance, every little detail.

Even with "high budget" productions, you don't shoot high speed for everything. It's reserved for special shots, and those are planned well in advance

However , if you are shooting something like wildlife, or sports, then high speed acquisition might be useful

[BamBamBigelow]

Well that explains the mindset. In photography, some of the best award winning shots are spur of the moment, "right time, right place" almost "lucky"

In contrast, in cinematography (theatrical, dramas) nothing is spur of the moment. Everything is scripted, planned well in advance, every little detail.

Even with "high budget" productions, you don't shoot high speed for everything. It's reserved for special shots, and those are planned well in advance

However , if you are shooting something like wildlife, or sports, then high speed acquisition might be useful

Yes. I completely understand what you are saying.

Decisive moment/Lucky Moment Vs Rigorous Planning

I aren't recording anything that is scripted/drama or theatrical. It will be a combination of a few things: street videography, nature and documentary.
There are going to be times during the genres I mentioned when I can plan every little detail in advance but equally there are going to be plenty of moments when I will see something I need to start recording immediately.

Thanks

[BamBamBigelow]

I have tried to find a video which demonstrates what I am trying to create in terms of the fps/slow motion.

This isn't my channel nor do I know the guy whose channel this is.

https://vimeo.com/107191927

[Cornucopia]

From what I can see there, this is an example of (original) 48 or 60 -> 24 (final), not 24 -> 12 duped to 24 or any other fudged method.
Just what pdr, et al., have been telling you.

Also, the motion doesn't look so slow as to have come from a 120fps source.

Scott

[BamBamBigelow]

So In conclusion 50p/60p would be the solution to my query. Then in post slowing it down to 24fps ?



Thanks

[jagabo]

So In conclusion 50p/60p would be the solution to my query. Then in post slowing it down to 24fps ?

That's ok for slow motion effects. But for shots where you keep the normal speed with a lower frame rate (ie, you just want to decimate) that will give you jerky motion. Because 50 and 60 aren't integer multiples of 24.

[BamBamBigelow]

So really there is no real option other than alternating quickly in camera between 60fps and 24fps?

How about if it was shot at 25fps which is a feature on some cameras?


I really appreciate the help from everyone on here. It is great there is a vibrant community that can quickly respond.

[Cornucopia]

You're in the UK, so yes, shooting at 50, slowing down to 25fps playback for the slomo shots, should work. However, if you are going to be using a mix between the 2, shoot at 50, slow down to 25fps for those special shots, then duplicate each of the frames and then run it again at 50fps. Or (shortcut), just duplicate frames (A,A,B,B,C,C,D,D,E,E...) during the "slomo" portion, leaving the native framerate at 50fps.
You will not get the same smooth look for both slomo and regular footage if you start by shooting at 24 or 25.

Scott

[smrpix]

Only you can determine if shooting everything in slomo is worth the cost in lowered resolution, higher bitrates, and increased post-processing. Certainly that video you linked to (or at least the parts I watched) would have allowed more than enough opportunity to switch between slomo and normal modes during shooting.

[jagabo]

In the comments the guy said he shot a mix of 24 and 60 fps.

[smrpix]

In the comments the guy said he shot a mix of 24 and 60 fps.

If that was a response to me, what I'm trying to say is BimBam ought to do some experimenting. All of the suggestions here yield different results and all of us came to this knowledge through trial, error, failure and serendipity.

[Cornucopia]

Might have been for me. Yeah, I didn't time the slomo or try do a 2x speedup test or anything. Was just eyeballing it, and it looked like the slomo stuff was either 48 or 60. If 60 was truly shot, that assures me I'm not going blind. I failed to mention in the 2nd previous post about some of the shots being standard 24, but I though that was obvious so I didn't comment on it.

Scott