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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Strobe ?

R

Rodrigo Lizana

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One of the major issues I´ve noticed when shooting with HD cameras is the strobe effect when panning. I never knew if it was due to the absence of an optical shutter or the all-in-focus characteristic of 2/3" chip size (which makes vertical lines in the background [specially bright ones] to remain in focus and strobe harder) or something else. Japanese manufacturers said the electronic shutter worked exactly like the optical one and there was no difference when comparing theirs with the optical one of film camera. People at Arri told me that they have noticed this effect when they tested some HD cameras along with film ones before the development of the D-20.
I´m wondering what´s the experience/opinion of the Red team in this subject ?.
 
Are you shooting in a progressive frame rate? There are two things you could be seeing, a progressive strobing or an interlace flicker, caused in ares of fine detail in interlaced footage. I'm guessing your seeing the progressive frame strobing though and sometimes if your not used to it, it can require an eye adjustment. There are several other factors you cuould research that would help minimize the strobing sush as watching your pan speeds.
 
Rodrigo Lizana said:
One of the major issues I´ve noticed when shooting with HD cameras is the strobe effect when panning. I never knew if it was due to the absence of an optical shutter or the all-in-focus characteristic of 2/3" chip size (which makes vertical lines in the background [specially bright ones] to remain in focus and strobe harder) or something else. Japanese manufacturers said the electronic shutter worked exactly like the optical one and there was no difference when comparing theirs with the optical one of film camera. People at Arri told me that they have noticed this effect when they tested some HD cameras along with film ones before the development of the D-20.
I´m wondering what´s the experience/opinion of the Red team in this subject ?.
Click to expand...

Hi,

IMHO the D20 strobes like other video cameras. I have only played with it at IBC several years running, but that was my initial reaction. I commented on CML and did not get flamed, so I guess that is accurate. Arri looked at my website and made no comment!

Stephen
 
With film, I often notice a stutter effect when panning at 24fps, but not at 30fps. When panning with any d-cine camera (F900,Varicam,Genesis etc.) it does look video-ish to me (IMHO), which I hate! :angry03:

Maybe the RED will eliminate this terrible side effect of shooting digital, I don't know? :unsure:
 
a one chip progressive digital cinema camera should not have any more strobing than a film cam panning at the same speed.
-A
 
Poi Boy said:
a one chip progressive digital cinema camera should not have any more strobing than a film cam panning at the same speed.
-A
Click to expand...

It shouldn't! But when you look at it, it does!

a one chip? You mean a cmos?

I see film stutter and digital strobe (or ghost?). What do you see?
 
Funny you guys bring that up, cause last night I was watching "Marabunta" a bad C serie TV movie shot in HD, and I was really annoyed at this stuttering wich was really videoish.
The whole time I was praying for the Red One to be exempt of such disease, wich would make the whole thing useless.
Of course, I can't imagine the Red team settling for that kind of crap.

Emmanuel
 
I guess that what I see is that stutter or strobing are more or less equally annoying. So if you are panning at 24fps with film or video you have to plan or adjust accordingly. I think the biggest culprit in making something look "videoish" is the deep dof that is inherent in three chip cameras.
Aloha
-A
 
Strobing is a factor of edge sharpness and DOF. HD and other video cameras have lots of added fake sharpness which adds to strobing, and find it had to get shallow DOF which really helps avoid strobing. After that, it's down to how fast you pan.

Graeme
 
If you pan with a subject, the studder, or strobe in this case, is much less noticeable. If you need to pan a shot with no subject to follow, the studder/strobe is much less apparent if the pan can last for about 7 seconds for any object to cross the screen. In other words, if you are panning to the left and there is a tree on the far left side of the frame, if it takes about 7 seconds for the tree to pass through the frame and disappear on the far right side of the frame, the studder/strobe will not draw attention to itself.

Hope that helps.
 
LighthouseMEdia said:
and sometimes if your not used to it, it can require an eye adjustment. There are several other factors you cuould research that would help minimize the strobing sush as watching your pan speeds.
Click to expand...

My observation was beyond basic technics. The strobe effect is something noticeable at "legal" panning speeds with or without a "subject" in the foreground. It helps to have something to use screen space and block the objects that are strobing but that doesn´t mean the strobe is gone.

Graeme posted an answer that´s new to me.
 
Panning speed is really a big part of the strobing equation when you shoot progressive.

If the HD cameras adding of sharpening adds to the problem, I can see the point, but to get a nice pan, you'll have to pan real slow and smooth, follow a subject (doesn't take away the strobing, but sure makes it less painfull) or pan real fast.

I see this in film, too.

It's easier with interlaced images.

Gunleik
 
gotta say, in the "milkgirls" clip, the girl's movement looks... well... there is no panning going on... it looks like a fast shutter kind of effect. if you look at it frame-by-frame, there doesn't seem to be much motion-blur on the girl's movement. I'm wondering what the settings as far as shutter speed were for that test.. it would be nice to know because I for one don't think it looks that great, I'm afraid. It's worried me a bit since ther first time I saw the clip
 
Sharpening in post will make strobing worse?

Sharpening in post will make strobing worse?

markp said:
gotta say, in the "milkgirls" clip, the girl's movement looks... well... there is no panning going on... it looks like a fast shutter kind of effect. if you look at it frame-by-frame, there doesn't seem to be much motion-blur on the girl's movement. I'm wondering what the settings as far as shutter speed were for that test.. it would be nice to know because I for one don't think it looks that great, I'm afraid. It's worried me a bit since ther first time I saw the clip
Click to expand...

When the "milkgirls" clip was first available, I pulled it into Final Cut to view it on our Sony PVM-20L5 monitor, test some color correction, etc. As I was playing it back again and again, I also noticed a little bit of storbing in their motion. Curious to see what it would look like with some sharpening, I used Final Cut's sharpen filter to harden up the edges. Now that was stroby! I don't consider that a very scientific test, but it certainly makes the case for avoiding any sharpening on high motion or fast pan footage.

You can also see this effect from in camera processing quite easily, if you take a Sony F900 or other camera that can shoot progressive and shoot the same pans and higher motion shots with the detail on and then with the detail off.

I think (and hope) your guess about high shutter speed is probably right, since I'd imagine they were anxious to show the shallow depth of field and wanted to keep the lens close to wide open. Depending on the amount of ND they had in front of the lens, if it was a bright day perhaps the shutter was a little higher than what most people would use on that shot so that they could keep the aperature open. But that its just a guess.

I've also played with some single CMOS cameras with rolling shutters and have found that sometimes I really needed to play with the shutter settings for each type of shot to get exactly what I wanted. We don't know what the actual shutter will be for RED yet, but with rolling shutters I found I needed to go with a higher shutter than I wanted to keep the effect of rolling shutter at bay in shots with higher speed motion in the frame. This particularly true for motion that is verticle or if the thing in motion is tall in the frame. Now there are certainly times you want that high shutter speed look on fast motion, but I hope we'll be making that choice for artistic rather than technical reasons.

Finally, just in case someone feels like I'm attacking Red (a common response here sometimes) I have very high hopes for the camera and do have a reservation. Like everyone else I'm very excited about the resolution, shallow depth of field and the potential for very great dynamic range ... I'm just very curious to see how motion and shutter play out in the footage.
 
Stepping frame by frame through the milk-girls clip, the motion blur does look more like what you would expect on film with a 90 degree shutter angle than a 180 degree one. Maybe this is the case. Can anyone from RED comment what the shutter angle (equivalent) was on that shot?
 
I definately noticed judder with the milk girls stuff. I took it as it was early on in the proccess and that red would fix it. I did not hear any complaints from anyone at the LA showing so I assumed it had been fixed. If there is motion issues like this it will be a huge problem. Anyone want to comment on what the LA footage demo looked like?

Can anyone with red comment on this?
 
I feel bad for mentioning it "only now" that other people start talking about it,
but only two days ago I was checking the "milkshot" again for that very same reason.
There seemed to have been an issue then, but like others I haven't got a clue why.
Any comment would be apreciated of course.

Emmanuel
 
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