Stuttering 4K Footage

[Jeremy Gadd]

I bought a Sony Z150 a few months ago. I am only filming in HD at the moment but was quite disappointed with my first test shot in 4K. The more I looked at it, the more I thought that it must be a camera issue as I can't believe that it should like this. I contacted Sony, who advised me to find someone near me that has the same camera so I could compare footage from both. That's not very practical as I really don't know anyone else near me that has one. Could someone have a look at a short clip I have uploaded and tell me what you think. I have uploaded it to Dropbox for download as I don't want to get any compression from Vimeo or YouTube. It's a .mxf file AVCLong codec, 56mbps 3840x2160 35fps progressive. I've added an HD file for comparison.

https://www.dropbox.com/sh/n8brdl95o...9VgwwVoXa?dl=0

Thanks.

[Cary Knoop]

I assume you realize that the HD version is 50p versus the UHD version being 25p.

I don't see anything technically wrong with it.

Obviously you have to limit your panning speed with 25p footage to get a smooth transition.

What was the shutter angle you used?
Is your monitor refresh rate set at a multiple of 25?

[Jeremy Gadd]

Ok thanks for taking the time to look at it. I'm not sure where to find shutter angle. Do you mean shutter speed? If so, it was 1/50 second.

I was doing a more exaggerated pan to compare it to the HD footage, which is 1080p 50fps.

Please forgive my technical ignorance when it comes to 4K as it's very new to me.

[Noa Put]

I also don't see any issues with the footage, looks normal to me when I view it in Edius. Like Cary said, if you shoot in 25fps instead of 50fps you need to do slower pans.

[Dave Blackhurst]

Didn't have time to check the clip, but a few things I learned quick about 4K - keep your shutter speed in manual, and keep it closer to the 30p (25 in your case?) frame rate, or you'll get very "stuttery" looking results from the motion in each frame being "frozen" (if you let the camera auto set to higher shutter speeds) - you actually need a little motion blur in the frames to prevent it looking like a bunch of really sharp stills. Be careful with camera motion...

And depending on your monitor, turn OFF any "sharpening" (my cheap 4K TV made everything look horrible, with shimmering everywhere...).

Once you get 4K sorted, you won't want to go back to HD...

[Noa Put]

And depending on your monitor, turn OFF any "sharpening" (my cheap 4K TV made everything look horrible, with shimmering everywhere...).

That shimmering effect is also what I see in high detail scenes like a wide shot with hedges in the background which produce a very noticeable shimmering effect probably caused by a too high shutter and a tv that is not able to deal with all the fine detail.

[Paul Kellett]

Look like normal 25p to me. You say HD is fine, i presume you were shooting HD at 50p
Does that camera not shoot 4k-50p (or 60p) ? If so that could be why.
Clip 2 is 50p, it's plain to see.
Sounds to me you want a camera that does 4K-50p


Paul.

[Jeremy Gadd]

Yes, I shoot HD at 50fps and have never used 25p before even with HD so this may be the issue. I just tried switching the camera to HD 25fps and it has that same 'stuttery' look. Horrible! As I mostly shoot handheld with my eye to the EVF that would give me a migraine as that's what I see in the viewfinder. As the camera doesn't do 50fps 4K it looks like I'll be staying in HD land for a while!! Very disappointing.

[Paul Kellett]

The lack of 4K-50p is why i didn't buy that camera, i bought the Panasonic HC-X1 instead, 4K-50p.

Paul.

[Jeremy Gadd]

Yes, in some ways I wish I had done the same now but having other Sony cameras it seemed the best choice for mixing multicam in terms of matching profiles for colour grading etc.

[Jeremy Gadd]

I think it was this that made me go 'Wow!' make sure you change playback settings to UHD.

Sony PXW-Z150 Test Footage - 4K VERSION - YouTube

[Paul Kellett]

No quick pans though, that would show the 25p stutter.