What happens if you layer an iPhone 4 with an iPhone 4S in a locked grip, then go walking and stumbling around to see how both behave as hand-held images?
Throw in some indoor / outdoor transitions in a long, continuous shot, and you might be able to see some behavioral differences that identify how Apple's HD video tech has grown in a year.
First off, the new iPhone 4S is 1080p30 at maximum. If you start shooting in dim light, it can drop to 1080p24 in an attempt to get more light. In dark areas, it sees better with less grain, but it doesn't tell you it has changed the frame rate.
If you shoot with the FiLMiC Pro app, you can force the iP4S to shoot 720p30. Aha!
I made very little attempt to shoot stable shots here. I was more interested in seeing how the internal "stabilization" of the iPhone 4S looked compared with a camera that had zero stabilization.
More importantly, I wondered how the average hand would behave with the new stabilization idea.
By slamming them up against each other, the iPhone 4 shows you what the full level of instability really looks like, and the iPhone 4S image shows you how much, or how little, the always-on stabilization accomplishes.
As you can tell, the iPhone 4S is actually a much, much better camera. Even when shot using Apple's rudimentary Camera app that's included on every iPhone.
The comment toward the end about the gold floor producing a blue cast works like this: The older iPhone 4 seeing the extra gold would tend to flatten it to neutral, artificially introducing blue into shadows and neutral grays. That was in my mind, but not well articulated by my mouth. At any rate, the iPhone 4S handled the late golden hour rays much better than its predecessor.
Apple uses gyro and accelerometer info to help stabilize the image, but they've kept the effect down to a low degree of correction. To do this sort of stabilization correction, one usually crops into the image slightly, then compares sequential frames to each other, performing slight pixel shifts to better align them, one to the next.
More shake reduction requires more cropping. That would be hard on the image. Obviously Apple has done the minimum to make the shot a little better, but not tremendously better.
You can freeze the image and compare detail on frames that are not motion-smeared or defocused. The 1080p30 image has a lot more going for it.
One could conceivably zoom into the shot to 67% scale without losing detail, compared to images shot in 720p. Certainly the images will require a lot less shading, correcting and grading. We expect FiLMiC Pro to come out with a much-improved Version 3.0 of that app for greater control.
Apple's iMovie and FCP X both have post-stabilization options. Those would allow you to crop to a greater degree and make much more smooth results. Maybe in a future video?
The iPhone 4S fits the Steadicam Smoothee camera holder made for the iPhone 4, and does it perfectly with both colors of iPhone 4S.
Here's a test video showing what typical shake is like with only the internal Stabilization, then with the addition of a Steadicam Smoothee.