Red strobe effect when panning... please help !

[Etienne Caron]

I saw a 2k projection of Red footage with a lot of strobing on the vertical lines on slow panning. This was enough to give a cold shower to producer and DP who were before so excited to see the resolution and the dynamic range of the camera.

The project is a short that we will blow to 35mm. Producer and DP call me today to tell me that for monday they want footage to go to 35mm as test of that problem.

Ive said to the producer that we dont know how they shoot the footage that we saw at projection... it could be anything that create the strobe !

I know the skew effect and that Red dont have a global electronic shutter, blah blah blah. But i'm wandering if i shoot 3k, 60 fps and after that in post, i speed the footage to look it was shoot in 24 fps (with audio sync) i could smooth the strobing/skew effect on fast panning, since they will be more shutter refresh on the CMOS sensor per frame.

please tell me that it make sense or tell me what should i do to stop the strobing effect on panning !

thanks

 

[lib]

This the the one thing that still really bothers me. On shots with vertical lines or area areas of high constast when panning too quickly stobing occurs. This also occurs on film cameras but the effect seems less pronounced, even when shutter is set to 360 it doesn't seem to soften the edges of the stobing area. It has been discussed before on this thread.

http://www.reduser.net/forum/showthread.php?t=17042

I think it would help if the red camera had a bit more motion blur when shutter is set to 360.

 

[Etienne Caron]

Hi lib,

Ive just finish reading the thread you refer me... Exactly what i saw at the projection. Clipping windows inside a church judding like hell on a very slow pan ...aaarrrgghhhh man!

Ive been told that in a scene where a woman walk left-to-right alone, there was no srobe... but when their is a lot of movement (ohter peoples walking left-to-right) there a lot of stobing of the caracter doing the same left-to-right walking.

Its a compression issue when there is too muh information in the shot ?, use Redcode 28 ? do slow motion in 48 fps and speed up 2x in final cut to have smoother pan ? use 1/40th shutter speed ?!

Got my Red today and have 48 hours to do tests that will convince people that this camera can do the job for a short blow in 35mm. Dont want to be bump by a HVX/Redrock M2 on this ! ;-)

Red is the most beautifull girl in the place and you realize at the last minute that she got something between her teeths... and you have to tell her !

 

[Filipo]

I have stobe effects when panning and I understand that, but I saw many RED footage without it.

It bothers me every day.

 

[reality]

This is very similar to what you'd see in film and other camera. There was a long thread about this elsewhere. the main difference seems to be in the contrast/highlight contrast and digital needing a bit more exposure time.

I've solved it for my shoots by going to 1/40th when the panning rates are likely to strobe or sometimes 1/30th for more extreme rates.

 

[jimhare]

This is very similar to what you'd see in film and other camera. There was a long thread about this elsewhere. the main difference seems to be in the contrast/highlight contrast and digital needing a bit more exposure time.

I've solved it for my shoots by going to 1/40th when the panning rates are likely to strobe or sometimes 1/30th for more extreme rates.

Exactly, I saw this on Genesis footage when I was watching projection tests. A slow pan across boat masts. They jumped and jiggled like crazy.

I was in a room of really talented and experienced operators and DOPs and when I asked about it, no one else said they noticed it, and that it looked great.

There are volumes written on pan speed ratios and the such. Be worth researching the science.

 

[James T Mather]

If you've come from using interlaced video cameras this will be a "problem" for you, if you've shot film for years it will be something you're used to. It's been around for years. There is no reason that a Redrock will perform differently than the Red camera.

Red's panning strobe looks the same as film IMHO.

There are rules for shooting to control strobing - avoid striped shirts, herringbone jackets, take care on panning shots with heavily contrasted vertical lines etc (exactly like yacht masts), observe panning speeds to avoid "stepping", etc . This is, amongst other things, what learning your craft is about: Managing visual problems. No format is bulletproof.

If I were the original poster I would insist on shooting the test myself rather than agreeing to third party stuff.

 

[Etienne Caron]

Thanks everyone for your respond

I come from both industry, video and film. We were at the 2k projection room at Technicolor and producer, dp and staff saw the stobing in all the highlights/high contrast area moving. All those persons have many years in experience with film and video.

Here a exemple of the stobing. You do a slow pan downtown and a building have vertical line, they will appear ok. But in your pan, when you arrive at the edge of the building and the sky, there is too much contrast and the edge is stobing too much.

And we all agree at the projection that thoses shoots were not usuable. But i'm not here to do bashing, i'm here to find solution because its my job and have 48 hours to do tests that will go to film print to see if stobing is a big issue.

I will try 1/40th and 1/30th today, those are flicker free at 24 fps ? And i might do 3k, variable speed: 48 fps on a 24fps time base project setting and speed up 2x in final cut to smooth pan and skew. That make sense ?

Thanks

 

[reality]

We did test with Genesis, film, and D20 independently about a year ago also and saw very much the same thing across all the cameras as we see on Red right now. I will say quite confidently there is nothing to be surprised about here.

Now I have heard stories of some rental facilities hyping up the strobing to move people from Red to higher priced cameras. (where they end up seeing the same thing, ha ha ha

 

[Etienne Caron]

I will rent some of thoses movies made by other digital camera and see by my self...

It must have a solution to this, beside waiting for sensor upgrade!

thanks

 

[reality]

It's a 24fps artifact. That's why some people prefer 60i or 48P.
You won't see it much on many films because pan rates are constrained
to limit the effect.

 

[Kjetil Haugen]

I will rent some of thoses movies made by other digital camera and see by my self...

It must have a solution to this, beside waiting for sensor upgrade!

thanks

Watch the "Everybody Hates Chris" series. Shot with F23. You'll see alot of it there. I think this is one of those downsides to the new superclean images on all the new cameras. Every frame is a perfect still image and put in sequence the strobing effect is more noticable. I hope there is something that can be done, though. When you first notice it, it is all you see from that point on... My suggestion: Dont point it out to people. It seems nobody really notice it unless they're made aware of it.

 

[Ariana]

Watching Oceans 11 in hotel last night I noticed lots of strobing on both action moving across frame and panning. I think people become hypersensitive and lose perspective on what are natural limits to shooting 24p. Strobing is actually one of the things that defines the 'film look' and induces the abstraction from reality.

There definitely seems to be something related to the size of the film or sensor. 16mm vs 35mm has a similar difference in strobing as large sensor vs small sensor.

 

[Etienne Caron]

35mm Camera recommended Panning Speeds:
http://www.gecko-cam.com/HTML/KNOW-HOW/panning-speed.htm

ex: 24f.p.s. with 50mm lens should take 29 sec. to pan 90° sweep !

There is tricks, like using smaller dof to blur the background during pan, avoid high contrast edges on verticals lines, blah blah blah...

got to deal with it i guess!

thanks

 

[Uli Plank]

While I didn't have the opportunity to test them side-by-side, I'm under the impression that the D20/21 can handle this a bit better, obviously due to the softer attack/release of the mechanical shutter.
According to my experience, all others with electronic shutters have the same problem.

 

[Kenn Michael]

Went to see 'Traitor' the other night. Shot 35mm and strobing all over the place. All the same motion stuff I've been seeing in the Red footage.

 

[Etienne Caron]

I send a hard disk today to the lab of our week-end test. Producer with check 2K digital projection and decide if they go with Red.

The strobe is obvious when panning accross building and you get to the dark edge of the building with the bright sky in background. I did 1/48th, 1/40th and 1/30th. 1/30th help, but its little too video. After we try handheld in a run and gun situation and was perfect... no judding from verticals lines who were not too exposed to high contrast and the skew was just alright, not too much eye disturbing

I said to the producer that Red, like any video or film camera, should use panning tricks to avoid judding. But seem to me that CCD cameras dont have that much of this issue and the Arri D-20, with his mechanical shutter, dont have that much judding to.

We will see... cross my fingers!

thanks again

 

[reality]

CCD, film, and CMOS all have the same issue which is directly related to 1/48 of a sec exposure at 24 fps. The main difference that people see are due to the fov differences between different cameras and how fast something travels across the frame.

 

[Patrick Tresch]

I also saw some panning problem but they where more a 2k projection problem as a RED one... wich refresh rate does the dlp have, 50/100hz? What connection RGB/HDMI?...?

Panning speed/focal length choice are always problematic... in some cases:shifty: .

I wouldn't go for a RED compression problem.

Hope to see the results of your test.

Patrick

 

[Monteiro]

To get back to the strobing issue. I have been very disturbed by it as I do architectural videos and panning across building interior and exteriors at anything other than a crawl makes the video virtually unusable even using a 360 degree shutter. I did some tests today and came across an interesting setting in the "Monitor" called "Open Gate" it virtually eliminates the strobing problem on the monitor but has no effect on the recorded footage. I am wondering if there is any way to route this setting to the recorder? I am no expert on film but in my understanding an "open gate" would mean the same thing as a 360 degree shutter which provides a 100 percent exposure of the frame while it is in the film gate. Someone correct me if I am wrong but maybe 360 degree or (1/24 sec) on the Red really doesn't mean the same thing it means in film. After all since the sensor is progressive scan and writes the image from top to bottom as opposed to a film exposure which exposes the entire film frame simultaneously a given pixel on the sensor only gets a tiny fraction of the exposure time (ie. 1/10,000 of a second or the equivalent of a very narrow shutter) so it would deem to me that the only thing that would help this strobing problem would be some kind of motion blending or motion blur setting. Is that what this mysterious "Open Gate" setting does? If so let's rout it to the recorder.

Thank