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"Wobbly" scrolling on new iPad

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paulisme

macrumors 6502
Original poster
Dec 15, 2008
408
9
Charleston, SC
Has anyone else noticed this? When scrolling a web page or similar content in other apps, touch the screen and move your finger up and down repeatedly at the speed you might use to scroll quickly to the bottom of a page. When I do this, especially on a page with a lot of text and images, I can see that the page content skews with the left side of the screen scrolling slightly ahead of the right side of the screen causing a "wobbly" effect when scrolling up and down. I can only compare it to the rolling shutter effect you get with some digital cameras when panning quickly while shooting video.
 
You can see it on this page by rapidly scrolling up and down. Isn't particularly great, a limitation of the insanely high screen resolution?
 
The iPad 2 does the same thing, although the new iPad might be slightly worse. It probably has to do with the refresh rate of the LCD being slower than the frame rate of the GPU during scrolling. After a while you don't notice it.
 
That's funny you say that because I that my eyes were screwy at first! But I kept going back and forth with the scrolling and it kept doing it. It's like the screen isn't keeping up on one side causing a crooked distortion...
 
All LCD displays do this, they don't update the entire panel at once.

Plasmas, for example, don't do this, because the entire panel is updated at once.
 
Surf Monkey said:
Link us to a page where it does this and we'll see if we can replicate the behavior.
Click to expand...

Try http://www.cnet.com/. Watch the gray header bars on the right side of the page, and don't scroll so quickly that everything is a blur. The bars will look like they're bent while scrolling up and down.

I also just realized I can only see it in portrait mode. When holding the iPad in landscape orientation I don't notice it.

I only previously owned the 1st gen iPad and never noticed it on that device, but it could be the higher resolution of the new iPad that's now making it obvious to me.
 
admanimal said:
The iPad 2 does the same thing, although the new iPad might be slightly worse. It probably has to do with the refresh rate of the LCD being slower than the frame rate of the GPU during scrolling. After a while you don't notice it.
Click to expand...

Agreed. My iPad 2 does the exact same. I'm actually quite impressed the iPad 3 isn't worse.
 
paulisme said:
Try http://www.cnet.com/. Watch the gray header bars on the right side of the page, and don't scroll so quickly that everything is a blur. The bars will look like they're bent while scrolling up and down.

I also just realized I can only see it in portrait mode. When holding the iPad in landscape orientation I don't notice it.

I only previously owned the 1st gen iPad and never noticed it on that device, but it could be the higher resolution of the new iPad that's now making it obvious to me.
Click to expand...

Nope.

Not trying to be short. I don't see this effect at all.
 
paulisme said:
I only previously owned the 1st gen iPad and never noticed it on that device, but it could be the higher resolution of the new iPad that's now making it obvious to me.
Click to expand...

It's not as noticeable on the iPad 1 because it has a slower GPU than the 2 or 3, so there isn't as much of a disparity between the frame rate and how quickly the LCD can refresh.
 
I've seen it on long text emails. You have to scroll up and down really quickly to notice it. It is not a problem, it's just the display trying to keep up. If you want to see it, email yourself the end-user license agreement from Apple and scroll up and down quickly
 
By swiping between the homescreens in landscapemode i noticed that the top app icons are faster on its places then the bottom Icons. Also noticed that Pictures transforms to parallelograms when swipe to an other.
 
I noticed that to.....

It's pretty subtle but I notice it the most when scrolling my timeline in Tweetbot. At first I thought my eyes were play tricks on me. It appears that it is simply a refresh issue, like having Vsync disabled.
 
Its very noticeable yes, but I cant say I'm too bothered by it at all.

In fact, if you use your thumb to scroll on the left hand side of the screen, it actually looks like your thumb dragging that is causing the effect :)
 
Tom359 said:
It's pretty subtle but I notice it the most when scrolling my timeline in Tweetbot. At first I thought my eyes were play tricks on me. It appears that it is simply a refresh issue, like having Vsync disabled.
Click to expand...
You beat me to it. It's probably a VSync thing. They may not have VSync enabled when not in a 3D app. Basically the refresh rate of the screen is slower than the fps trying to be displayed on it, so it drops part of the frame and replaces it with a new one. For most LCD's this is 60Hz or 60FPS. So if the scrolling speed is exceeding what can be displayed at 60FPS it will drop and substitute parts of each frame giving you that "wobbly" or chopped effect.
 
The older iPads do this as well. It has to do with the display itself reprints it's pixels. It does it from one side to the other, not all at the same time. It's not a vsync issue as there isn't actual tearing, just wobbly images.
 
arterio said:
You beat me to it. It's probably a VSync thing. They may not have VSync enabled when not in a 3D app. Basically the refresh rate of the screen is slower than the fps trying to be displayed on it, so it drops part of the frame and replaces it with a new one. For most LCD's this is 60Hz or 60FPS. So if the scrolling speed is exceeding what can be displayed at 60FPS it will drop and substitute parts of each frame giving you that "wobbly" or chopped effect.
Click to expand...
No, LCD displays do not update the entire panel at once. it's not a framerate or v-sync issue.

You can see this effect on any LCD. Just try moving around large windows side-to-side on your computer display for example. Most people just don't notice it, the effect is just far more obvious with a touchscreen device, and at the speeds the iPad lets you scroll.
 
This is normal, sadly. Does it on my iPhone 4S, and I've noticed it on my iPad 1, 2, and 3. Bit of a bummer, but just the way it goes..
 
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