C100 Mark II & Sachtler FSB 4 : Jittery Footage

[Wayne Smith III]

Hello,

I recently purchased the C100 Mark II and Sachtler FSB 4 Tripod. I've been using this camera for months at work with limited problems in terms of picture quality. However on my personal C100 Mark II, I have noticed that when I perform any type of movement (particularly pans and tilts) the camera produces a strobing effect similar to interlacing. I can’t tell if the strobing is a mechanical error derived from the tripod or a setting within the C100 Mark II. As I began to take on new clients this type of behavior can not persist.

I have attached two examples of the problem filmed in two separate environments.
Please help so I can get the most out of my investment.

EX : 1

C100 Mark II & Sachtler FSB 4 : Jittery Footage - YouTube

EX : 2

C100 Mark II & Sachtler FSB 4 : Jittery Footage - YouTube

[Nate Haustein]

Shutter speed and frame rate being used?

[Wayne Smith III]

Everything is pretty open. 1/24 & F3.5 in the bedroom clip. Frame rate 23.98 frames. But even when i adjust those things its still pretty strobe-y. Is it just me? Is this normal?

[Dan Brockett]

Very normal. Wayne, I am going to refer you the ACS (American Society of Cinematographers) manual on panning speeds. You are shooting footage at 23.98 fps using a an S35 imager. The simple explanation is you are panning way too fast for your frame rate. If you want to pan and avoid strobing, which is what I am seeing in your video clips, you either shoot at a faster frame rate or you slow your pans way the heck down. Or you will get strobing. This has nothing to with your camera settings or your tripod head, it's the way you are operating that is causing it. Another variable is your shutter angle.

Panning Speeds for frame rates at 180° shutter

[Michel Edelenbosch]

180degree shutter is 1/48 not 1/24 that is the reason for the strobing

[Wayne Smith III]

Originally Posted by Dan Brockett

Very normal. Wayne, I am going to refer you the ACS (American Society of Cinematographers) manual on panning speeds. You are shooting footage at 23.98 fps using a an S35 imager. The simple explanation is you are panning way too fast for your frame rate. If you want to pan and avoid strobing, which is what I am seeing in your video clips, you either shoot at a faster frame rate or you slow your pans way the heck down. Or you will get strobing. This has nothing to with your camera settings or your tripod head, it's the way you are operating that is causing it. Another variable is your shutter angle.

Panning Speeds for frame rates at 180° shutter

Thank you!
I get it!

I'll slow it down.

[Wayne Smith III]

Originally Posted by Michel Edelenbosch

180degree shutter is 1/48 not 1/24 that is the reason for the strobing

Interesting, can you explain a bit further?

Also guys, I noticed there was a section in the "camera setup" menu that said "shutter" with four different options including "speed" "angle" and "off". Could this be part of my perceived issue?

[Wayne Smith III]

Hey guys. So this time I'm shooting F2.8 ISO 400 & 180 degrees. I hear what you guys are saying but something still isn't sitting right with me. After reviewing this clip again, it appears almost like the frames are freezing (digitally) at certain parts making the footage even more choppy. I'm very confuse about this. Do you guys have any other guesses?

https://www.youtube.com/watch?v=GJuZ...ature=youtu.be

[Michel Edelenbosch]

are you using an lens with IS (image stabilizer)? some versions wont work well on tripods.
As a rule it's best to turn them off on a tripod move.

The 180 degree rule is that what ever your framerate is, your shutter speed should be double that.
I live in PAL land so when shooting 25p my shutterspeed will be 1/50 when shooting 50p it would be 1/100 etc..

[Dan Brockett]

Does the footage on a monitor have the same skipping as your YouTube clip? I see it. It could be IS on tripod artifacts, YouTube compression or your compression to make it manageable size to upload to YouTube? It seems to be worse when you move faster, less when your moves are slower?

[Wayne Smith III]

Originally Posted by Dan Brockett

Does the footage on a monitor have the same skipping as your YouTube clip? I see it. It could be IS on tripod artifacts, YouTube compression or your compression to make it manageable size to upload to YouTube? It seems to be worse when you move faster, less when your moves are slower?

Yeah,
It's in the monitor, footage and the compressed export. I'm sending it to Canon tomorrow. They think it might be a sensor issue or something internal. It really sucks because I have a shoot on the 8th and they're quoting me a two week turn around. I tried it with 3 different lenses and two different tripods. Just my luck, I would be given the defect of the litter. :(

At least its still under warranty.

[Dan Brockett]

Please report back once you get your camera back from them, it would be helpful for others to hear what the cause was.

[Barry Goyette]

Originally Posted by Wayne Smith III

Hey guys. So this time I'm shooting F2.8 ISO 400 & 180 degrees. I hear what you guys are saying but something still isn't sitting right with me. After reviewing this clip again, it appears almost like the frames are freezing (digitally) at certain parts making the footage even more choppy. I'm very confuse about this. Do you guys have any other guesses?

https://www.youtube.com/watch?v=GJuZ...ature=youtu.be

Looking at this on youtube...on a very old slow computer...I get some of the lagging frames you're talking about...but when I play through it again, everything looks fine...(meaning in my case, it's on my machines end). Other than typical motion "judder", I don't see anything wrong. Quite often viewing 24p on a field monitor or even the camera LED, especially if you're indoors under flourescent lights...will look a little jerky...a slow cadence really.

Depending on your intended output, you may find that shooting in 29.97 is a better option. We all want to project our projects on the big screen, but realize that the rest of the US (tv, internet) works in a 60hz world...so 29.97 will always look smoother due to both the increased frame rate and fewer issues with flickering lights, and playback frequencies. Or go "cinematic" and discipline yourself to play by those rules, or simply be a rock star and flout them :-)

[Gary Huff]

Originally Posted by Barry Goyette

Other than typical motion "judder", I don't see anything wrong. Quite often viewing 24p on a field monitor or even the camera LED, especially if you're indoors under flourescent lights...will look a little jerky...a slow cadence really.

I have to agree with Barry here. I think your issue is stemming from moving the camera around too fast in 24p. You can send your camera off if you want, but I think Canon will say it's operating normally and you'll be out time and money.

[Jon Fairhurst]

Before sending it to Canon, I recommend some more scientific tests. If you have access to a turntable or other smooth moving thing (maybe even the turntable in a microwave, if the glass is clear enough), then put an object on it, lock the camera down, and record at various shutter speeds. Next, review the footage one frame at a time. You can look at the length of the motion blur and measure the gaps.

To do it accurately, use a small object with high contrast like a white line over a black background. You don't want the line to be, say a silk thread. If it's too small, it will disappear with motion blur. If it's too wide, it will be hard to find where the object stops and the blur starts.

Frankly, I don't think that there is a problem. Put a subject in the frame and move the camera smoothly, and the results should look good. Inconsistent motion with no subject to look at is just begging for us to see flaws.

All that said, there is a dirty little secret with digital video cameras - the response during the shutter interval isn't necessarily even. As the electronic shutter opens and closes, there can be variations in the gain. That can potentially cause a sharp leading or trailing edge. If this happens, the shutter interval might be exactly right, but we will see a bit more strobing because of that hard edge. Think of it like an organ note vs. a plucked string. When you press the key of the organ, the note starts and plays evenly until you lift the key. That's how a shutter should work. Now consider the plucked string. It has that moment of sharp attack, followed by a decaying note. You can pluck the next note at the exact moment that the previous note stops, but we will easily detect the change. On the other hand, with a pure organ tone, if the notes play back to back to back, it will just sound like one long note.

So the camera might be working properly - and yes, there might be a bit of an artifact from the camera. The key is to use good, smooth moves while following a subject, and the problem will disappear. Note that you can also do a whip pan as it's so fast and disorienting that you won't notice the strobing. But please use whip pans sparingly.