Other: Motion Cadence

J

JCummings

Well-known member
With the release of the latest Blackmagic Ursa Mini Pro G2, I've been hearing a lot people commenting about it's perceived superior "motion cadence" compared to other cameras. I assume that means a more cinematic feel of 24p.
It's not something that's really been on my radar and I've rarely seen it discussed fully, but I swear I've owned other cameras that I thought handled it better than my current F5.

Is it something real to you or is it one of those intangible things you might think you notice but can't quite identify? How could it possibly differ between cameras when the settings are identical?

Or is the discussion rather like audiophiles debating the different sound characteristics of speaker wire...
 
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It's intangible but I believe in it. Rent a RED and see if it confirms your thoughts.

And of course it will differ between two cameras because they are completely different machines.

There's also no BMCC MK2...lol. You're combining BM's first camera with Japanese nomenclature.

It's the UMP G2 or BMPCC 4K.
 
NorBro said:
It's intangible but I believe in it. Rent a RED and see if it confirms your thoughts.

And of course it will differ between two cameras because they are completely different machines.

There's also no BMCC MK2...lol. You're combining BM's first camera with Japanese nomenclature.

It's the UMP G2 or BMPCC 4K.
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Corrected, thanks.
 
It depends on who you ask. Some people swear they can see it, some people swear that it doesn't exist. Online discussions often become very heated about this topic in particular and words like "magic" and "mojo" start popping up. It can be difficult to remain objective. Here's a previous thread about it: http://www.dvxuser.com/V6/showthrea...cadence-compares-to-others-in-its-price-range

For me it's real, but with the caveat that I think there are two visual characteristics in play:

1) Smooth motion: Does 1/48 at 24fps look oddly staccato, kind of like it was shot at 1/120? This can be a tricky one if you are looking at footage shot by other people because a lot of YouTubers will speed up their shutter to manage exposure rather than carrying around an ND, and then make no mention of it in the video description (which is their prerogative).
2) Pleasing motion: This one is harder to put a finger on. Sometimes there is no staccato, but the moving image just doesn't look quite right. Some have theorized that it has to do with the sharpness and micro-contrast of the individual frames because using softer lenses or blurring the image slightly in post seems to improve things.

The litmus test I am always looking for is a shot of a busy city street shot at 1/48 in 24fps. Do the moving pedestrians look pleasing, or does something look off?
 
I remember my 5d2 - as well as the famous slanted fence posts - I could clearly see people in motion having 'saggy' faces.

Clearly every 24/5p frame is not the same.

Is this just rolling shutter or more?

I do believe that compression can do wierd stuff especially the funky compressions (anything but tif, raw, prores)

Im not sure that at the higher end one could tell one camera to the next.
 
I had some issues around this years ago when I first got an EX-1. A friend hated the camera compared to his HVX200 because he swore the motion was choppy at 24P. Eventually i concluded I could see the issue on both cameras but it stood out more on the EX-1 only because it was much sharper. The only time it was an issue was shooting moves on classic model boats with rigging and lots of detail against a black background and I think that was with an F3. It bothered the hell out of me but the client didn't notice anything at all and was thrilled with the sharp footage. I tried reshooting similar shots at home with different shutters and speeds and a few different cameras and never was able to get rid of what I saw. I eventually just threw up my hands and forgot about it. Have never noticed any issues since then. Beats me what was going on but I am interested if you learn anything. Could have been related to the monitors rather than the camera.
 
LennyLevy said:
I had some issues around this years ago when I first got an EX-1. A friend hated the camera compared to his HVX200 because he swore the motion was choppy at 24P. Eventually i concluded I could see the issue on both cameras but it stood out more on the EX-1 only because it was much sharper. The only time it was an issue was shooting moves on classic model boats with rigging and lots of detail against a black background and I think that was with an F3. It bothered the hell out of me but the client didn't notice anything at all and was thrilled with the sharp footage. I tried reshooting similar shots at home with different shutters and speeds and a few different cameras and never was able to get rid of what I saw. I eventually just threw up my hands and forgot about it. Have never noticed any issues since then. Beats me what was going on but I am interested if you learn anything. Could have been related to the monitors rather than the camera.
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Of course back in the days of the EX1 and F3, many monitors and electronic viewfinders didn't have as many display/resolution options -- and much of what was being shot at 24p might have been output by the camera in such a way that it integrated a 3:2 pulldown into the output. As I recall when shooting in 24p, the F3 would only output to HDMI using a 3:2 pulldown. At the same time, its dual link bnc's would output 4:4:4 at actual 24p for external recording.
 
Pulldown means that you are seeing an irregular frame cadence. First of all, you are watching at 30fps rather than at 24fps. So your sense of visual refresh rate is different.
Also, the pulldown is how the camera makes 30 frames out of 24 -- which as you recall is irregular, essentially making some of your 24 frames stay visible longer, and others less so. So once you split each of your 24 frames per second into 2 fields each (thus 48 fields/second), every other frame becomes 3 fields rather than 2, thus adding 12 fields. Because of the way this is done, some resulting frames (remember, each frame is 2 fields) end up being a combination of two different frames, while others stay the way they were originally.
Thus motion displays differently than it would if the monitor is running at 24 instead of 30...

https://en.wikipedia.org/wiki/Three-two_pull_down

Of course the DVX100B created an alternate kind of pulldown, slightly different motion duplication and no 'combined' frames...
 
JCummings said:
Or is the discussion rather like audiophiles debating the different sound characteristics of speaker wire...
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Haha, we’re starting to get there.

The motion cadence is a thing. Just like a flourescent bulb can be annoying. 24fps is not that fast. Fast enough to create the illusion of motion, but it does fall apart when pushed.

How different is the flicker on your tv with the flicker of a cheap LED bulb? Idk, but it is annoying.

Even film projection in movie theaters project at flicker rates of 48 or even 72 strobes per second.

If you capture 24p digitally and play back digitally at 24hz, why are we surprised it looks odd?

Try setting your screen to 48hz, or 72. Or any exact multiple of 24. (Make sure motion smoothing is off) If that doesn’t improve it, then try frame double, not interpolated frames, but exact duplicates of each frame, and export a 48fps video. and then set the screen to 48hz, and see if that improves anything.

But an issue could be that 23.98fps doesn’t play well with the round numbers of 24hz, 60hz, 120hz, and 240hz that tv’s commonly scan? Idk.

The other aspect is does the video look “video-y”. If it does, that may influence our ideas of trhe motion cadence.

People have been complaining about digitally sourced 24p since the Varicam at least.
 
You question reminds me of this thread.

Here's one plausible answer from that thread:

Kholi said:
YES.

You are not crazy, it is not your computer screen, you're just sensitive to it. I am as well, and so are some of my friends. High End digital cinema cameras are tuned to make sure cadence is similar to film. DSLRs are mishaps.

I've posted this since I started using Canon DSLRs, but only a few people actually go out and try it:

USE 1/45(CANON) or 1/40(GH2)

As much as I want 1/48 settings, I actually don't care anymore. 1/40 on GH2 looks right. 1/45 on Canon looks great.


http://vimeo.com/38260236

(Video's from DVXuser: LIN3ARX, someone else who tried 1/40 after the suggestion and is sticking to it now)


http://vimeo.com/33016592

Ignore my shakey hands... coming off of shooting 30lb MX setups and Epic GH2 is way too light to try and hold. xD


http://vimeo.com/12284829

7D @ 1/45


http://vimeo.com/37406049


5D @ 1/45
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That was a good read!

This was another good semi technical post:

j1clark@ucsd.edu said:
If I understand the 'argument'... there is a very slight blurring effect due to the shadow of the shutter on a Real(tm) Film camera. In the case of the 'digital' camera, that shadow is 'lost', and the 'edge' is much
sharper... so, by going to 1/40 rather than 1/50 (I think those are the only options for the GH-1. Other cameras may have other intervals...), one gets a slight bit more blur, which for some people apparently is a significant effect.

As I've said elsewhere, if one looks this close to 'film film' movies, one will find out all manner of manipulations of shutter speed, framerate, and eventual screen presentations... not to mention loose sprockets and worn sprocket holes on the film, as well as dust and scratches, in the 'traditional film film' projection theater... and that's assuming the projectionist has focused the projector correctly... got the right lens on... and any number of 'problems' I've seen setting in theaters...

I would also hazard that any slight effect like the motion of the shutter, relative to bluring a moving object, exists only in certain situations, and at specific distances and angles of travel relative to the camera, and perhaps even angles of travel of apparent motion across the film plane relative to the shutter motion...

This sort of effect has been well known. Old 4x5 view cameras that used a rolling slit shutter across the film plane, would result in distorted images of things that move across the film plane as the slit rolled up or down. The result was seen mostly in race car wheels and would make them look somewhat oval.

This 'effect' actually became a indication of speed where a person drawing a 'racing car' would distort the wheels in the same way...

As I recall most people didn't notice at all, or emit cries of 'it's not real', when a leaf shutter between the lenses became more popular and did not have this sort of effect... And while 35mm Real(tm) film SLR cameras also had a slit shutter, the effect was minimized by just being able to move the shutter elements faster... but it was still detectable... in some situations.
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Well this thread quickly went over my head but I will say I once owned an Panasonic SDX900 (a very early 24p standard-def camera) that used some sort of pulldown scheme (24pA?) that resulted in a very pleasing motion look. Or maybe it was the 3 CCD's?
Anyway, I can honestly say I've haven't owned a camera since then that produced 24p motion as nicely. But looking at some of the latest footage from the newer Ursa Mini G2 camera, I was reminded of that SDX camera I had.
Sorry I didn't see that earlier thread. I know it may all be in my head, or I maybe I'm sensitive to it. Mojo indeed.
 
James0b57 said:
Haha, we’re starting to get there.

The motion cadence is a thing. Just like a flourescent bulb can be annoying. 24fps is not that fast. Fast enough to create the illusion of motion, but it does fall apart when pushed.

How different is the flicker on your tv with the flicker of a cheap LED bulb? Idk, but it is annoying.

Even film projection in movie theaters project at flicker rates of 48 or even 72 strobes per second.

If you capture 24p digitally and play back digitally at 24hz, why are we surprised it looks odd?

Try setting your screen to 48hz, or 72. Or any exact multiple of 24. (Make sure motion smoothing is off) If that doesn’t improve it, then try frame double, not interpolated frames, but exact duplicates of each frame, and export a 48fps video. and then set the screen to 48hz, and see if that improves anything.

But an issue could be that 23.98fps doesn’t play well with the round numbers of 24hz, 60hz, 120hz, and 240hz that tv’s commonly scan? Idk.

The other aspect is does the video look “video-y”. If it does, that may influence our ideas of trhe motion cadence.

People have been complaining about digitally sourced 24p since the Varicam at least.
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Which brings up something I’ve been wondering for a while... Why haven’t we gotten rid of the “non-whole number” frame rates, yet? I understood the reason for them ‘back in the day’, but now, it should be an historical oddity. Obviuously it couldn’t just be done away with, equipment, software, etc. would have to be able to handle existing footage, but moving forward, it should all be whole frame rates(24.00, 60.00, etc.), just like all 4K/UHD is progressive scan, no more interlace.
 
Run&Gun said:
Which brings up something I’ve been wondering for a while... Why haven’t we gotten rid of the “non-whole number” frame rates, yet? I understood the reason for them ‘back in the day’, but now, it should be an historical oddity. Obviuously it couldn’t just be done away with, equipment, software, etc. would have to be able to handle existing footage, but moving forward, it should all be whole frame rates(24.00, 60.00, etc.), just like all 4K/UHD is progressive scan, no more interlace.
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Tell the networks that broadcast 1080i -- not to mention the rest of them that choose to stay at 720p.
Though perhaps the manufacturers would like the idea of selling all that new gear!
But realistically, how much are you actually gaining by switching from 23.976 to 24, or 59.94 to 60 ? Is it worth scrapping your old cameras that don't shoot at 'even numbers?'
 
OnSet said:
Tell the networks that broadcast 1080i -- not to mention the rest of them that choose to stay at 720p.
Though perhaps the manufacturers would like the idea of selling all that new gear!
But realistically, how much are you actually gaining by switching from 23.976 to 24, or 59.94 to 60 ? Is it worth scrapping your old cameras that don't shoot at 'even numbers?'
Click to expand...

Did you read my post?
 
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