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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 :)

Rolling Shutter - how concerned should I be?

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Peter Plevritis

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Hello all.

Been carefully reviewing this forum to get info from the pioneers that got in early. Thank you all for sharing what you've learned.

Images look fantastic. So many pluses to the camera but with new things there are problems to be worked out.

I've been trying to keep up with a few of them: blue channel noise, ergonomics issues, highlight edges, lack of multiple outputs, camera (fan) noise, QC, and a few others discussed here. Most seem addressable.

But the one that's got me the most concerned is the rolling shutter skewing.

Michael Hastings' Nasa Chopper footage reveals quite a bit of it during the fast pans. Is this just a fact with a CMOS camera? Can there really be anything done to minimize or eliminate the skewing (besides not panning fast)?

Unless I missed something - I haven't heard if this issue was even addressable.

Thanks
Pete
 
Pete said:
Hello all.

Is this just a fact with a CMOS camera?
Click to expand...

No, rolling shutter is not necessarily tied to CMOS sensors. Though, currently, many CMOS sensors in digital cameras employ rolling shutter. But CMOS can have global shutter.

Please see the following article:

Martin Wany and Georg P. Israel, "CMOS Image Sensor with NMOS-Only Global Shutter and Enahnced Responsivity,", IEEE Transactions on Electron Devices, Volume 50, Issue 1, pp. 57- 62, Jan 2003.
 
This has already been talked to death. You can find rolling shutter skew in film cameras as well. Its something that's there and can be worked around. If your going to be throwing your Red camera down a flight of stairs and its flipping end over end...or side to side. Then yes you will get some skew.
 
Drew599 said:
If your going to be throwing your Red camera down a flight of stairs and its flipping end over end...or side to side. Then yes you will get some skew.
Click to expand...

A simple quick pan across vertical objects will reveal it as well. And I oughtta know...
 
It must surely be pure oversight on the DP's part that so many feature films are now being shot on RED with this HUGE skew problem.

Try it. If it is a problem for you, don't shoot RED. If it isn't a problem... there you go. We have not had one camera returned because of skew.

Jim
 
skew is no big issue with red after all i have seen.
more RS problems are flashlights and gunfire, so you have to know about this when planing shots with these content.
 
Maybe it's just the way I'm reading some of the posts but perhaps I hit a sore spot. Didn't mean to do that. I was just asking a question.

And I got an answer to my basic question. Is this just an inherent characteristic of the camera? It seems it is. Thanks for clearing that up.

Pete
 
If skew is a problem highly depends on what you are doing with it. In most situation you wouldn't notice it. In some you would and then in some cases you can fix that in post.

No camera is perfect and RED is no exception. But you learn to accept its shortcomings because of the beautiful images you get.
 
Let me clarify. When I do a fast pan I see skew on vertical objects. However, what I am seeing is not cause for alarm, nor do I think it would be noticeable to most viewers. I do not consider it to be an issue with the camera, but it is good to be aware of. I just wanted to point out that you don't have to throw your camera down the steps to see it.

Here's a still frame of a fast pan across a railing. I should add that when the move is done at a speed that would be considered acceptable for 24fps the skew is not noticeable.

8131_1204979335.jpg
 
filmcameras are similar to this. for me skew is definitely no problem with red,
 
The skew is not a serious issue. . . but the REAL issue, related issue, and it IS a HUGE issue, is the inability to film emergency vehicles with their strobe lights a-flashin'. I have not received our camera as of yet (MONDAY!), but the emergency vehicle issue is going to turn out to be very constraining to a lot of people. It's just going to prove plain impossible to film police, firemen, or an ambulance with this camera.

Stephen
 
Stephen Pruitt said:
The skew is not a serious issue. . . but the REAL issue, related issue, and it IS a HUGE issue, is the inability to film emergency vehicles with their strobe lights a-flashin'. I have not received our camera as of yet (MONDAY!), but the emergency vehicle issue is going to turn out to be very constraining to a lot of people. It's just going to prove plain impossible to film police, firemen, or an ambulance with this camera.

Stephen
Click to expand...

I shot a cop chase the other day (night)...what was the problem with strobes that I was supposed to get?
Pic's were perfect, Match the 35mm camera that was used on the other side of the road. So good were the images in fact that we opted to drop the takes from the film camera because the grain was a bit rough.

I think you shot wait till you get your RED camera before you judge.
You will be (Like all of us who have one) pleasantly surprised. :glare:
 
I'd like to see how this camera handles motorsports like motocross specifically.

Picture being on the floor of a supercross standing 5ft from where the bikes fly by. Can you say in-cred-i-bly fast pan?
 
To be honest, at first I was really concerned with this issue. However, I have really studied a lot of the material that everyone has been providing (thank you all so much for doing that by the way!!!) that I really feel this is not an issue to me anymore. Rolling shutter is there on fast pans and I have seen it in some of shots posted. I have seen it with a subway train going by upclose as well. (Which personally, I thought looked cool)

Now you guys are going to think this is nuts, but in some ways, I actually liked it in some of the shots. With a natural mixture of motion blur, I don't think any viewer is going to pick up on anything.

I agree- film cameras have it as well. As DPs we just need to know limitations of our tools, and I don't think this is an extreme limitation for the RED. I think it was Macgreggor (sp?) who showed a pretty extreme example of it in one of his fast moving shots. I agree that this camera may not be the best for a Borne Identity kind of look. Crazy handheld shots with whip pans and things of that nature should most likely be avoided if you don't want the rolling shutter effect to kick in.

I just finished sending RED my money for this camera because I really think this is an outstanding tool, and I really like what these guys are doing. I really do believe in their vision, and I am ready for the wild ride!

Jim, I do have a quick question though- I remember reading a while back that the sensor will be around 10 percent faster on build 15. Is this still the case? I am just curious.
 
Skew doesn't seem like much of a problem; it's only really noticeable when the camera moves so fast motion blur would hide it anyway (unless you were specifically looking for it...)

But a bigger one deals with 60hz discharge lamps....

On film (or with a CCD) you can shoot HMIs, flourescents, sodium vapor, etc. at 1/48th, 1/60th, etc.

Apparently, with a rolling shutter, not only is 1/48th unusable, but some people can't even get 1/60th to work; there's major banding. This is definitely a problem, since not everyone can afford flicker free HMIs or replace all fluorescent lights with kinoflo fixtures (or avoid shooting outdoors at night where there are streetlights!)
 
Policar said:
Skew doesn't seem like much of a problem; it's only really noticeable when the camera moves so fast motion blur would hide it anyway (unless you were specifically looking for it...)

But a bigger one deals with 60hz discharge lamps....

On film (or with a CCD) you can shoot HMIs, flourescents, sodium vapor, etc. at 1/48th, 1/60th, etc.

Apparently, with a rolling shutter, not only is 1/48th unusable, but some people can't even get 1/60th to work; there's major banding. This is definitely a problem, since not everyone can afford flicker free HMIs or replace all fluorescent lights with kinoflo fixtures (or avoid shooting outdoors at night where there are streetlights!)
Click to expand...

There were a few scenes in Jumper (not the ones shot with Red) where the lights flicker quite a bit, I didn't hear anyone complain about it in the theatre.
 
Read/reset will be 10% faster in Build 15. Faster is better.

Jim
 
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