Canon C70 jittering

utisz wrote:

do you have any idea what is causing that terrible jitter of antialiasing in the footage that I recorded with my C70?
Is the digital stabilization which is messing up my clip or something else?

Almost certainly related to the digital stabilisation, yes.

I did use a 50mm prime for the shot.

So no lens IS, right?

I was wondering however what is the purpose of Digital IS on C70 as the IS version of the RF lenses doesn't necessarily require any additional Digital IS.

If you handhold the camera with an IS lens, there is no way to stabilise for roll (rotation of the image about the centre of the frame). Lens IS can’t do that. So there is more and more shake as you look toward the corner of the image. The corners often show visible rotational jitter. Unlike pitch and yaw shake, this rotational shake does not depend on focal length, so you can’t make it look smoother by using a shorter focal length. You need the digital IS to correct that, but as you’ve noticed, there are downsides to digital IS. IBIS works much better because it can rotate the sensor to correct for this shake properly.

I am still convinced that the problem is not lens related, but it is due to the line-skipping algorithm of the 4K sensor in Digital IS mode.

Does the C70 really line-skip in digital IS? Even if it doesn’t, there will be unavoidable rolling-shutter artefacts.

The solution for all of this is a tripod or gimbal. But obviously IBIS is a useful feature for this kind of handheld shot. Lens IS would be better than nothing, though. Lens IS in combination with a monopod would be worth trying. The monopod would stop rotational shake, allowing the lens IS to correct the pitch and yaw shake.

Thanks for your answer.

As a matter of fact, I was using a non-IS lens. Most of the time I grab the 50mm EF 1.2L and this particular footage was also recorded with that lens.

The other thing that I noticed is that C70 exhibits more moiré artifacts than R7 or R5 cameras, even when Digital IS is turned off. This sound absurd as C70 is using a 4K native resolution and not a line skipping or downscaling method like the above-mentioned cameras. (Yes, I am always using my C70 in its native resolution.)

Only my copy is affected, or this is a common phenomenon with the C70?
Thanks.

utisz wrote:

The other thing that I noticed is that C70 exhibits more moiré artifacts than R7 or R5 cameras, even when Digital IS is turned off. This sound absurd as C70 is using a 4K native resolution and not a line skipping or downscaling method like the above-mentioned cameras. (Yes, I am always using my C70 in its native resolution.)

I have a Panasonic GH5S that, like your C70, has a 4K native resolution. It too has more moiré than I would expect, sometimes more than non-video-specialist cameras that record more pixels and downsample (e.g. my Olympus E-M5 Mark III). I think it is caused mainly by the impossibility of making perfect optical low-pass filters (anti-aliasing filters) and the need to preserve as much detail as possible (in other words, the OLPF cannot be strong or other users would complain the picture is soft).

Of course there are big benefits to the C70 and GH5S having fewer pixels, mainly higher frame rates without throwing pixels away and much less rolling-shutter artefacts (because the readout speed is higher).

Only my copy is affected, or this is a common phenomenon with the C70?

I don’t have the C70 but doubt there is anything wrong with yours from your description. Digital IS causes artefacts, and (separately from the digital IS problem) moiré is sometimes unavoidable because of low pixel count and weak / non-cliff-like OLPF.