@ChainsawFilms you'd (theoretically) have identical "slants" in both normal and ETC

Please see the 720p grabs. The ETC and non-ETC slants are the same.

@mpgxsvcd

Please take a look at my drawings of the angle of skew grabbed from your truck shoot. As you say, the 1080 shots at 24 fps are a bit too blurred to extrapolate a true angle. - yet I've had a go at it anyway. Do you really want to bother trying 1080 again?

Thanks for your work.

As Jamie says, to Adam, "Yes, I think we can say, 'This myth is busted."

@Roberto. Busted? Actually not, unless you provide us a proof that all the trucks moved AT THE SAME SPEED. This might be just speed fluctuation. A scientific test requires panning two GH2s hard mounted on top one another, one in normal the other in ETC mode against a vertical line. Or you shoot with one GH2 twice but you have an object that moves at a fixed speed (a toy train for instance). The basic point is that only angles measured at the same speed of camera/object interaction are relevant. Which is unfortunately not the case with your test.

@brianluce

Same again. The more of us testing this, the better.

Here's the test I made. The idea is fairy simple. I fixed a slider with metal roller wheels truck against the bar of the shelving unit. The truck has holes with thread where I fixed a long enough bolt.

Same exposure ISO 640, F/4.5, 1/100 in both shots. I made dozens of attempts to be sure that I can catch the frames with the truck position as close as possible. Remember this is free falling, so it's essential. I also chose the beginning of the fall frames where acceleration is low. I missed the focus in ETC off attempt, but it doesn't matter for this test methodology.

No need to measure angles, it is CLEARLY visible that ETC mode suffers less from rolling shutter skew.

So much for our myth busters.

I don't know why you guys keep testing this stuff with high shutter speeds when no one shoots like that. Sorry for being snarky, but it just seems like this is a dead horse, shooting in a real world situation easily shows that ETC has less skew.

zigizigi, your results will be more accurate if tested near the bottom of the fall, not the top. Under constant acceleration due to gravity, change in velocity with respect to change in time is constant, which means that change in velocity with respect to change in position is minimized when the velocity is maximized. Accounting for wind resistance, change in velocity with respect to change in time or change in position is also lower when the velocity is higher.

Using a faster shutter speed will give a clearer image without changing the magnitude of the rolling shutter skew.

I just aligned them and pumped the shadow details. Isn't it perfectly clear now that there's quite a substantial difference in skew?

Roberto, what were you saying about perception earlier in the thread? :-)

I am personally determined to apply the best science here. The paint is drying on my rotating-cylinder system and I hope to use it on both jello and shutter tests.

As scientists, we must be perfectly at ease with a state of uncertainty. As individuals, we feel a pressing need for closure.

We all have to suppress our desire to see any particular outcome. It's not a football-match. I hope we don't see any more "science by mob rule" here, or "science by vote".

I was prepared to stop experimenting here because until @ziggiziggi most comments were at best, unsubstantiated by any experiment or at worst, gratuitous. Now I'm enthused to see what's happening. I just can't believe it all hasn't been done before by Panasonic.

Roberto, it's good that you doubt your own opinions and that of others. Love to know what pixels you are choosing to align your yellow line on ziggiziggi's frame grabs, seems they are selected biased towards your own theory.

@zigizigi

One more thing: I'm now calibrating my spinning barrel using a household incandescent light at 50hz. I will be shooting tests in non-strobing daylight and I think that would be a good idea for all of us.

I hate to bring this up again, but there's a very good case for some experiments with higher frame rates or shutter speeds. At present we're seeing jello skew which then gets motion-blurred and it's hard to tell the two apart.