RED ONE Jello effect

[Marcel André Morin]

Hello all,

I will be in shooting a shortly heli to boat, boat to boat and underwater to boat. We will be shooting all red and yesterday i got a mail from the client w/ a few concerns. He has recently come across some info. regarding the "wobbly" or "Jello" effect caused by single CMOS cameras.

I was wondering if any of you have experienced this and if you have if there are any work-around's that you would be willing to share.

below is a portion of the mail i received:

______________________

What you lose in the deal

As always, there are some trade-offs and the Canon EOS 5D Mark II is no exception. The first issue is recording time. The Canon 5D uses CF (CompactFlash) memory cards. These are formatted as FAT32 and have a 4GB file limit. Due to this limit, the maximum clip length for a single file recorded by the 5Dmk2 is about 12 minutes. Unlike P2 or EX, there is no provision for file spanning. The second issue is that the camera records at a true 30fps – not a video friendly 29.97 and not the highly desirable film rate of 23.98 or 24fps.

Audio is considered passable, but for serious projects, double-system, film-style sound is recommended. This workflow would be the same as if you were shooting on film. Traditional slates and/or software like PluralEyes (Singular Software) or FCPauxTC Reader (VideoToolshed) make post syncing picture and sound a lot easier.

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Example of the rolling shutter effects used for interesting results

One major limitation cited by many is the rolling shutter that causes the so-called “jello” effect. The Canon 5D uses a single CMOS sensor and nearly all CMOS cameras have the same problem to some degree. This includes the RED One. This image artifact arises because the sensor is not globally exposed at the same point in time, like exposing a frame of 35mm film. Instead, portions of the sensor are sequentially exposed. This means that fast motion of an image or the camera translates into the image appearing to wobble (http://vimeo.com/4041788) or skew (http://prolost.com/blog/2008/11/5/subway.html). In the worst case, the object in the frame takes on a certain rubbery quality, hence the name the “jello” effect. It can also show up with strobes and flashes. For example, I’ve seen it on strobe light and gun shot footage from a Sony EX3. In this case, the rolling shutter caused half of the frame to be exposed and the other half to be dark.

Skew or wobble becomes most obvious when there are distinct vertical lines within the frame, such as a lamp post or the edge of some furniture. Fast panning motion of the camera or subject can cause it, but it’s also quite visible in just the normal shakiness of handheld shots. If you notice many of the short films on the web, the camera is almost always stationary, tripod-mounted or moving very slowly. In addition, lens stabilization circuitry can also exacerbate the appearance of these artifacts. Yet, in other instances, it helps reduce the severity.

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Note the skew on the passing subway cars

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any help would be really appreciated =)

marcel

 

[Stuart English]

Jello

Jello

Your answer back lies in this comment

"nearly all CMOS cameras have the same problem to some degree. This includes the RED One"

But it's also true that film cameras do this too. It's the degree (speed of sequential scan) that is the critical issue.

 

[Darren Orange]

Your answer back lies in this comment

"nearly all CMOS cameras have the same problem to some degree. This includes the RED One"

But it's also true that film cameras do this too. It's the degree (speed of sequential scan) that is the critical issue.

Hey Stuart,

Do you have any film examples? That might be cool to see or helpful or know where to get some? Maybe David Mullen might have some or know of some?

 

[Marcel André Morin]

So is it a degree or shutter speed that can be changed to avoid this or does it happen at random times when frequencies meet w/in a frame?

 

[Kaku Ito]

I was the Mr. Afraid of the Jello effects on video cameras before and believed in CCD based cameras and I raised my voice for warning people about CMOS camera like EX1. That is because when I shoot my own, I shoot hard action mountainbiking and street sports type of things. I think many know me as early adopter of HVX100.
Then after got involved in treating R3D footages and thought, well, I do see the jello effects here and there but RED ONE is not a video camera. You have to shoot like the film camera and many many o†her characteristics and the features that I can't get on other cams that don't have the jello picture problems, I switched all of my work to RED ONE. Imagine this, I was just a videographer type of guy then now, I got involved in three major feature films and many many TV ads and music videos.

The bad jello video are coming from EX1 and 5DmkII. I've done tons of comparisons shooting the same thing with 5DmkII and RED ONE then I'd rather not include clips from 5DmkII just because of the bad jello picture.

 

[Graeme Nattress]

The read/reset time (the time that directly effects skew) is much less on the R1 than on the 5D2 for instance. That means for any given amount of camera or scene movement, the amount of skew is always less on the R1.

It's also worth noting that tube cameras of old also scanned the image sequentially in a rolling shutter manner. And this is also not a CMOS issue, but a sensor readout issue that can effect any type of sensor. You can get CCD with rolling shutter, and as Stuart mentions, Film with it's mirror shutter has an equivalent.

Graeme

 

[Denis Buhot]

wombat...

wombat...

real name ?? )

However, I d'love to think of it as an irrelevant issue, but...

I'm in the wildlife shooting field... Panning rules are all very fine, trouble is : wild, fast moving animals are poor readers, and some need big lenses. All I could find about fast moving animals shot with a red one were slo-mo shots. If Gibby or anyone can prove me wrong on that, I'd be very, very happy. To me, that would be quite a relief.

Because what I get at regular fps/shutter speed (i.e 25 fps/1/48s), are shots that are stuttering terribly against any fixed background, whenever the background is not totally blurred and out of focus. However smooth the camera move is, in order to follow the subject, the shot does stutter. Distance is comfortable, relative speed moderate, focal length quite usual - if not rather small - in my field (300mm). Stutter all the way.As said in this board by others than me : you'd better switch off the opengate option of your viewfinder in order to get an approximate idea of what the footage will look like. In my case : almost unusable.

I recently sent a usb stick to the people at Red, containing stuttering shots of an eagle flying against a rocky background. Hardly bearable... Even a brisk reframing against a grey sky causes the image to stutter. Question is simple : is the stuttering "normal", meaning it can't be avoided but can be adressed either by post or monitoring options.. Then what ? Is it a simple monitoring issue ? Can a solution similar to opengate be used in post, so you can get a smooth rendering ? or when monitoring, or broadcasting ? I haven't got a satisfactory, simple, straightforward answer yet.

In case the stuttering I see can't be worked around, then the answer is simple : the red one simply can't be used to capture moving subjects, even at moderate speed, when the background is not totally out of focus. Slo-mo is the ONLY solution at hand (sigh...)

However, the fact is that soderbergh's che includes many fast moving action scenes, with smooth rendering, and I truly wonder how it has been made possible.

So please, red people, prove me wrong !!

 

[Graeme Nattress]

Stuttering is a different issue to skew. So let's tackle stuttering: It's directly related to the fps you shoot. If you shoot 24fps and pan fast you will get stutter. It's not something unique to RED, but directly related to the fps. Shoot fps on any other camera and the stuttering is there.

24fps only really "works" due to a combo of factors - controlled camera moves, putting the background out of focus and keeping edge contrast low (as in no electronic edge enhancement) which makes it easier for RED and Film to not stutter at 24fps (due to large sensor and no electronic enhancement) than a smaller sensor video camera. Make all things equal though, and you're back to stutter.

Graeme

 

[James Brundige]

buhot (got a name?) I'd love to hear what happens with the footage you sent to Red. The only time I have had stutter (on pans) is when I shot 24 fps and played back on a 30 fps timeline. FCP does not tell you, but it does a really bad pull up in background. I fixed the problem by converting in cinema tools (producing a 6 fps speed up) which looked great. clearly not good for sync scenes.

 

[Mark Wilkinson]

I had rolling shutter skew issues when shooting with my Red from camera car to picture car - with no gyro - the circumstances created a very dynamic wobble.

The Foundry plug did a pretty good job removing it:

http://www.thefoundry.co.uk/pkg_overview.aspx?ui=47C4AB50-4636-4326-87D1-FB380B2119EF

 

[Stephen Pruitt]

Hey there, James. . . Buhot IS his name. . . he's from the same family as the French impressionist printmaker/painter Felix Buhot (whom we collect).

Stephen

 

[Denis Buhot]

thanks Graeme...

thanks Graeme...

24fps only really "works" due to a combo of factors - controlled camera moves, putting the background out of focus and keeping edge contrast low (as in no electronic edge enhancement) which makes it easier for RED and Film to not stutter at 24fps (due to large sensor and no electronic enhancement) than a smaller sensor video camera. Make all things equal though, and you're back to stutter.

Graeme

Clear answer this time.

However, I've used rather small sensor video cameras on birds in flight against even sharper backgrounds (small sensor, big lenses not needed, plenty of DOF). No stuttering.

What I get from your answer : if you shoot scenes you can't be in total control of, then you'll have to use slo-mo. Sad end, to me.

What I don't get : if open gate works in the red viewfinder, why no such similar technique for other monitoring options ?

 

[Graeme Nattress]

With open gate shooting at 24fps you're effectively seeing 48fps. If you shot at 48fps, all would be the same. When you shot with smaller cameras, did you shoot interlaced video at 50i or 60i or did you shoot 24p?

Graeme

 

[Denis Buhot]

Graeme, you're right...

Graeme, you're right...

With open gate shooting at 24fps you're effectively seeing 48fps. If you shot at 48fps, all would be the same. When you shot with smaller cameras, did you shoot interlaced video at 50i or 60i or did you shoot 24p?

Graeme

I was shooting interlaced.. that must account for the difference. Just one more question : If I get you right, I'd better shoot 48fps, but then (apart the fact I have to forget about 4K) , how do I avoid slo-mo ? Do I have to choose a 48fps base frame rate for my project ?

 

[Denis Buhot]

thanks Stephen...

thanks Stephen...

Hey there, James. . . Buhot IS his name. . . he's from the same family as the French impressionist printmaker/painter Felix Buhot (whom we collect).

Stephen

Buhot is my name indeed Sad thing my ancestor was not a specialist in computer science...

 

[Graeme Nattress]

Well, for TV work you'd shoot 50fps or 60fps, and that would mean dropping to 3k on RED1. Interlaced video runs at 50 or 60 fields per second, which is why you didn't see the stutter - the camera was taking over twice as many pictures per second.

Graeme

 

[Denis Buhot]

Yes... very clear

Yes... very clear

Well, for TV work you'd shoot 50fps or 60fps, and that would mean dropping to 3k on RED1. Interlaced video runs at 50 or 60 fields per second, which is why you didn't see the stutter - the camera was taking over twice as many pictures per second.

Graeme

thanks again... if I shoot at a 180° angle, I'm in bad need for a new 800 iso sensor...

 

[Blaire Johnson]

You don't need to shoot 60P which isn't a standard format, if your were shooting interlaced then yes, but the Red One does not shoot interlace. 60i is the same as 30P.

So that means your Project Timebase should be 29.97, if you doing a TV finish. Shoot 4K 2:1 30fps which eliminates what you feel as unacceptable stutter and should also help with any rolling shutter artifacts, since it is a smaller sensor area which is the reason for the artifacts. In my tests/experience 3k does not have the absurd rolling shutter artifacts that 4k or 4.5k can have.

 

[Graeme Nattress]

Blaire - 60i is not the same as 30p! 60i shoots 60 images per second which get assembled into fields. 30p shoots 30 images per second. 60i is twice as smooth as 30p.

30p is indeed smoother than 24p, but not "that" much smoother.

Graeme

 

[Denis Buhot]

thanks Blair,

thanks Blair,

So that means your Project Timebase should be 29.97, if you doing a TV finish. Shoot 4K 2:1 30fps which eliminates what you feel as unacceptable stutter and should also help with any rolling shutter artifacts, since it is a smaller sensor area which is the reason for the artifacts. In my tests/experience 3k does not have the absurd rolling shutter artifacts that 4k or 4.5k can have.

thanks all, it helps a lot !