If you referring to yello as a problem than there is a simple solution. Use some polarizer filter or ND to lower shutter speed. With shutter at 1/1oo and lower yello is almost completely not visible compared to faster shutter speeds.

I routinely use 1/50 second on the GH2/GH3 and Canon DSLRs and jello is totally visible. Shooting with slower shutter speeds does not solve it at all.

@gizmo high shutter speeds do not at all stop the artifacts produced by rolling shutters, though motion blur may help to mask it. But then if you're gonna stabilize in post that motion blur is gonna look awful.

For helicopter shooting, definitely go for a global shutter camera with a good optical stabilizer.

EDIT: I just realized I just repeated what was in the last few posts before mine, sorry about that..

@balazer I don't see how lowering motion blur will do anything for any moving image. Motion blur is essential for video. Motion Blur is the only way to produce the illusion of motion out of a series for still images As @Roberto said,

"A tight shutter angle will constrict motion blur. A wide shutter angle will allow it. A 180° shutter angle is considered normal. ..Tight shutters create a stuttering stop motion animation look.."

from http://www.personal-view.com/talks/discussion/comment/55924#Comment_55924

Motion smear on the other hand, can be produced from excessively slow shutter. Not a good look.

Motion blur isn't essential, but it's desirable.

Using a fast shutter speed is a compromise. Normally you would like a shutter speed around 1/50 or 1/60 s. The problem is that ordinary optical image stabilization technology doesn't work very well in a helicopter. The technology is designed for shaky hands, not intense mechanical vibration. Just look at the kinds of stabilization solutions that are out there for helicopters: they're highly specialized, utilizing gyros and damping. Even if your camera has a global shutter, you're still left with the stabilization problem.

Software-based image stabilization works well for frame-to-frame movement of the camera, but it can't correct for motion within frames. The blurry frames are obvious and look bad in the context of video that is smooth and sharp otherwise. Using a fast shutter speed can alleviate that. There's even software to add motion blur back in to simulate a slower shutter speed. (Twixtor)

I'd suggest testing cameras in a car. Mount the camera to or hold it against the dashboard or some rigid part of the car to increase the vibration.

Hello, if necessary, you can use "RollingShutter" by the foundry ( http://www.thefoundry.co.uk/products/rollingshutter/ ) It for sure not gonna fix your shot at all (don't expect miracles) but if the rolling shutter is soft, it may help you a bit to get the look you want.

There are also a few tricks available with compositing software to "reduce" rolling shutter. They are not extraordinary, but they can help.

If you can wait a bit, you have the possibility to rent a Black Magic Cinema Camera 4K with global shutter and if you can't wait I suggest you to take a look at Sony F5 and F55.

I know this is pointless but the Nikon J1 is probably a good choice it has minimal rolling shutter especially at 60fps in 720p, or 60i 1080.. Its a great camera and very small so very useful.

If your budget is tight, use an unmanned drone/quadcopter and mount something like this on it.

If your budget is not tight, there's of course some great cinematic cameras around... ;-)

I assume @janis meant faster shutter speeds, when he said lower. Shooting at 1/100 or even faster would definitely help with rolling shutter. Think about it: you are forcing the full sensor read-out to occur in less time, in other words increasing your scan rate. Rolling shutter is the result of a slow sensor read-out / scan rate, so faster shutter speeds reduce it.

If you want a camera with no rolling shutter how about a blackmagic production camera (4k) it has global shutter.