Motion Cadence

[jonpais]

We've heard a lot from forum members claiming to see stark differences between cameras in the way they render motion, so this thread is for all those who wish to post comparisons. I'll start things off with a comparison between an $800 smartphone and a $50,000 cinema camera. I believe the two cameras were both set at 4K UHD 24p. It would of course be best if the posted videos were all shot at 24p.

Edit: Side-by-side tests only please!

[markr041]

I don't have a post, but I watched that video.

How does one achieve the 180-degree shutter rule on the cellphone in bright daylight? In the screen shot of the cell phone, the shutter speed was 1/800th for 24P. The cellphone has no ND filter and in fact no aperture either - so it is wide open in sunlight. If the "motion cadence" at 24p with a 1/800th shutter is ok, something is wrong. Somewhat off-topic, I do not see any log gamma setting for cell phones in Resolve Studio (unlike for Slog or Vlog. etc.), so it is not clear that ACES or Resolve Color management can be used with the cell phone clips. Nor is the LUT he used designed for any cell phone log gamma, leaving aside color space.

[jonpais]

@markr041 If in fact the shutter speed was 1/800th sec on the cellphone, great! Then we should see an enormous difference in motion cadence, but I don't. Preferably, the clips members post will be at 24p with shutter angle at 180 degrees.

[markr041]

2 minutes ago, jonpais said:

@markr041 If in fact the shutter speed was 1/800th sec on the cellphone, great! Then we should see an enormous difference in motion cadence, but I don't. Preferably, the clips members post will be at 24p with shutter angle at 180 degrees.

I didn't see a movement difference either - but the real point is we don't know what he did for the shutter - if he did something, he is hiding that fact. If he did nothing, it suggests the 180-rule is bogus. A scientific principle is you don't reject established theory with one badly-documented experiment. I would love it for the 180-rule to be wrong, since neither action cams nor cell phones can easily adhere to it and it would eschew the need for ND filters on serious cameras. Hardly likely.

[jonpais]

I chose this clip at random. Cellphone probably not the best idea for the reasons you cited. But it's good you pointed it out, since it would be preferable for posters to be able to ascertain the frame rate and shutter angle. I'm hoping to see comparisons with the mirrorless cameras that so many here claim have atrocious, deal-breaking motion cadence.

[BTM_Pix]

I'm not suggesting he did anything to mislead but the screen shots of him adjusting WB etc were of a completely different scene to the actual comparison footage with the RED.

Can't see an ND filter on it (as they're usually clip on with smartphones so would be visible on the stuff where he's showing it on the gimbal with the RED).

However, perhaps the most salient point here is that neither can you see any ND on the lens on the RED, so that would suggest they would both be on 1/800 hence why they aren't showing any difference.

[Inazuma]

For me it's only really noticeable with handheld (shaky) footage where cameras that have slow readouts will have a wobbly image. IBIS can negate this but can also end up introducing artifacts of its own. Plus there's the weird feeling of lag as you pan the camera, the image is always slightly behind where the camera is exactly pointing - although the end viewer won't know.

[jonpais]

I'm not really interested at all in the LG vs Red comparison, as I have no immediate plans to shoot a film with either. This topic was started to allow readers to post comparisons between different mirrorless cameras.

[jonpais]

57 minutes ago, Inazuma said:

For me it's only really noticeable with handheld (shaky) footage where cameras that have slow readouts will have a wobbly image. IBIS can negate this but can also end up introducing artifacts of its own. Plus there's the weird feeling of lag as you pan the camera, the image is always slightly behind where the camera is exactly pointing - although the end viewer won't know.

Exactly. Often I think it's either the IBIS or AF-C pulsing, or sometimes strobing effects due to fast panning that are mistakenly attributed to whatever motion cadence is. The rest are probably because of incorrect shutter speeds.

[TwoScoops]

I remember reading the ASC guideline for how fast you should pan 90 degrees is something insanely slow (like a minute or more.) This rule was around in the film days, so it's a digital thing, but someone new might think their fast pans looking strobey = the cameras fault. Obv some still handle it worse though.

[Inazuma]

There are some people that are extra sensitive to motion cadence though. @Oliver Daniel (who does a lot of professional work) was talking about this stuff way before most people on this forum

[jonpais]

If that is so, at least a few of the hundreds of camera reviewers out there must also be sensitive. But they’re not. Pretty much only in these forums. Anyhow, maybe some of those who claim to see these differences can contribute video comparisons. 

[markr041]

5 hours ago, jonpais said:

I'm not really interested at all in the LG vs Red comparison, as I have no immediate plans to shoot a film with either. This topic was started to allow readers to post comparisons between different mirrorless cameras.

Yes, but we learn from this one example that such "comparisons" need to be completely described as to settings. I think we would notice if a 24P action video was shot at 1/800th shutter even if we are completely skeptical about the concept of motion cadence. And, to maintain a 1/50th shutter when the aperture is at F1.6 (!) and the ISO is high as in log gamma would require one heckuva ND filter - 32X? I know of no such thing that attached to cell phones. On the ARRI, you can close down the aperture a lot. I think the comparison was faked.

I have left a comment at the video site, inquiring about the shutter speed issue.

[jonpais]

I think he used the same camera for both.

[mkabi]

5 hours ago, markr041 said:

If he did nothing, it suggests the 180-rule is bogus...

I would love it for the 180-rule to be wrong...

I never really questioned it. I myself only disobey it for when I need to use Twixtor.

Then again, I have also seen videos where the videomaker disobeys it and it still looked good. But, really.... It depends on what you are filming too.

In any case, all talk and no action doesn't mean anything to most. So here is a video, explaining and showing (with an example) why most follow the 180 degree rule:

 

[jahwah]

Doesn't the perception of motion cadence result from a combination of factors including compression, camera movement, contrast, lighting, shutter technology, shutter angle, foreground/background action and on and on. I remember the guy who made the digital Bolex felt that the global shutter allowed the camera to capture motion better than a camera with a rolling shutter. Here's a video that they made with a dancer who claims the digital Bolex is the only camera that replicates the way her movements look live (not sure what that means in relation to the idea of "cinematic motion cadence" but it's still an interesting idea):

 

[webrunner5]

I don't know. I grew up and shot with Wind up Film movie cameras that got slower as the spring wore down, battery powered ones that sort of got slower as the battery wore down, and I don't think anyone noticed or even cared if they did. And they got wonky as hell the worse they got, and the older the camera got.

It still is story is king and if you are entranced by the story, looking at motion variances is probably the last thing on your mind unless it slows down to a crawl, and hell you probably thought that was part of the movie to begin with. Man that was pure genius.

I think we all worry too much about the small stuff. Content is the whole point, not engineering perfection. Sure try to get most of it right, but I don't think Motion Cadence is up there at the top of my must do list.

Also if that dancer thinks she did that whole routine at perfect timing perfection I have a bridge to sell her.

.

[KnightsFan]

16 minutes ago, jahwah said:

Doesn't the perception of motion cadence result from a combination of factors including compression, camera movement, contrast, lighting, shutter technology, shutter angle, foreground/background action and on and on.

I'll add to the list: pulldowns and artifacts from watching a 24 or 23.976 fps file on a 60hz monitor.

If we bundle those factors as "motion cadence," I think we all agree that they are verifiable, measurable differences. However, many of them are produced by the scene and compression, not the camera itself. Comparing motion cadence based on compressed files streaming over the internet might not work so well, I think.

[jonpais]

@jahwah First, Pina Bausch - what a brilliant choreographer! Still, from what I've read, rolling shutters actually perform better in low light than global shutters. I've got no idea, since I've never shot a camera with global shutter. I'm still waiting for someone to share a side-by-side comparison between the most popular brands of mirrorless cameras. 

[jahwah]

I forgot to add "psychology of the viewer" to the list too. When these sorts of tests are done blind the results are often startling to the viewer. All of the camera fan/hater stuff goes out the window and people's minds open and change. Geoff Boyle has done some great tests this way on CML and very accomplished DPs often are surprised by what they like/dislike when they don't know what the tools are that were used to produce the image and have to judge the image alone without any of the tool allegiances/preferences we all carry around.