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Old November 20th, 2007, 04:34 PM   #1
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Rolling Shutter?

Has anyone (or can anyone) taken a look at some of those fast pans in the tennis or office footage? What's the general feeling about the severity of the rolling shutter, based on the real footage we've just gotten?

I have no way of single framing yet to judge this, until I can actually import the files successfully into FCP...
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Old November 20th, 2007, 04:45 PM   #2
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I looked but did not see anything. This stuff may not be the right place to "try" to find it.
The office stuff was 25P so quicks pans, or real close fast motion shows the expect motion blur associated with these frame rates.
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Old November 21st, 2007, 07:13 AM   #3
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When using shutter speed at 50 and shooting in 720/25p I can confirm the the rolling shutter effect is quite apparent if you go out of your way to make it happen. I pointed the EX at a fence panel and panned rapidly back and forth, the result was the the vetical posts seem to bend slightly away from the direction of the camera. I haven't noticed it yet with normal shooting. There are loads of shutter options on this camera though, not only can you set speed settings, but you can define the shutter parameters using another three methods so it may be possible to reduce the effect.

Personally I didn't find it that much of a problem, it kind of mimics what happens if you pan your head fast too and almost enhances the sense of motion. When would this be a problem during normal shooting to the point that it would be noticeable?
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Old November 21st, 2007, 09:20 AM   #4
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Well, I'm not sure what slight means, but it doesn't sound like much.
Also, I would NEVER take a cam and pan it back and forth rapidly and use that footage, especially at 24 or 25P.
First of all, it would be nothing but motion blur.
But, having said that, I would of done the same thing to look for the rolling shutter skew.
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Old November 21st, 2007, 09:36 AM   #5
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It reminds of the effect you get when you put a pen between your fingers and wobble it from side to side making the pen look like it's bending.

Here's a couple of grabs. As I said though, this may be due to a setting I was using or it might be possible to reduce the effect by changing settings.
Attached Thumbnails
Rolling Shutter?-roll1.jpg   Rolling Shutter?-roll2.jpg  

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Old November 21st, 2007, 09:40 AM   #6
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I'd be curious to see how it looks at 720p60 (or p50 in PAL land). That's the rate people may use to shoot sports and slow down to 24, 25, 30fps. One might try this at various shutter speeds too.
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Old November 21st, 2007, 09:45 AM   #7
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I'd be curious to see how it looks at 720p60 (or p50 in PAL land). That's the rate people may use to shoot sports and slow down to 24, 25, 30fps. One might try this at various shutter speeds too.
Why would somebody shoot at 50p and then reduce it to 25? I guess for slow motion but surely at normal speeds it wouldn't make any difference. I know the frames would only be exposed for half as much time so there wouldn't be as much blur, but would that be the same as just doubling the shutter speed at 25p?
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Old November 21st, 2007, 09:47 AM   #8
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Paul, thanks for the images.
How did you perform this experiment, holding the camera and moving side to side, or was it on a tripod?
If you believe you stayed on axis, there's no doubt it's there.
Will it be a problem with normal shooting, I seriously doubt it. But, it may be a concern for some.

There's trade-offs in all these sub 10K cameras, as can be seen in the still frame comparison shown earlier. For me, it's the footage I'm looking at 99% percent of the time, not the occasional 1%. Not to mention, anyone interested in shooting 24 or 25P are extremely careful in camera pans.
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Old November 21st, 2007, 09:59 AM   #9
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How did you perform this experiment, holding the camera and moving side to side, or was it on a tripod?
It was done on a tripod, so the camera stayed level throughout. I have shot some footage showing cars on the road which may prove to be more useful in terms of a real world test, I've asked Chris if he can host the mp4's.

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Old November 21st, 2007, 10:16 AM   #10
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Specifically for slow motion. 50p and 60p are often used for sports to get nice slow motion shots (short of using special high speed cameras).

Quote:
Originally Posted by Paul Joy View Post
Why would somebody shoot at 50p and then reduce it to 25? I guess for slow motion but surely at normal speeds it wouldn't make any difference. I know the frames would only be exposed for half as much time so there wouldn't be as much blur, but would that be the same as just doubling the shutter speed at 25p?
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Old November 21st, 2007, 10:16 AM   #11
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What are seeing with the cars? The car footage that went up this morning did not show any issues.
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Old November 21st, 2007, 10:28 AM   #12
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No issues with the cars themselves, the only time I see the effect (and it's difficult to make out) is when panning back to reset the shot past some lamp posts and a fence. As you say, it's hard to imagine a time when you would be panning at such high speed during a take.
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Old November 21st, 2007, 10:48 AM   #13
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True, and even then you're using it as an effect at which I could care less if it's a tad cantered.
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