GH4 GH4 in the park with Cinevate Duzi

[jaypass]

Hey everyone! I just picked up a Cinevate Duzi slider, so I decided to take it to the park for a test run...here's some footage! The slider is super smooth. Almost too smooth, I found it challenging to keep my moves slow enough because of how smooth it is.

https://vimeo.com/125751018

Used the 12-35mm Lumix lens, shot a combination of 4k/24p and 1080/60p. Cine D Flat mostly, graded using Film Convert.

On a side note, I've been reading a ton about the "judder" on panning at 24p with this camera. There's a plethora of complaints about it on different forums. I understand the concept of panning speed and the effect on motion at 24p, but I'm curious as to why it's so much more prevalent on the GH4 then any other camera I've used. I can do some pretty smooth pans on my AF100, but when I try a similar pan with my GH4 at the same speed, the image is juddering across the screen. I'm going to start playing with shutter angle a bit more to combat this. I usually shoot with it at 180.

I left several shots from this shoot out of my edit because the judder was driving me nuts. It's actually a little bit present in the shot of the trees at about the 1:00 mark, on the trees in focus in the background. Just bugs me, looks very unnatural.

 

[Batutta]

On a side note, I've been reading a ton about the "judder" on panning at 24p with this camera. There's a plethora of complaints about it on different forums. I understand the concept of panning speed and the effect on motion at 24p, but I'm curious as to why it's so much more prevalent on the GH4 then any other camera I've used. I can do some pretty smooth pans on my AF100, but when I try a similar pan with my GH4 at the same speed, the image is juddering across the screen. I'm going to start playing with shutter angle a bit more to combat this. I usually shoot with it at 180.

You should watch the footage on a native 24hz monitor or projector. When I plug my camera into my projector and watch footage at native 24hz , motion looks much, much smoother than on my 60hz monitor. On a 60hz monitor it's repeating frames in an uneven cadence that exaggerates the judder. You could also try a refresh rate that's a multiple of 24 if your monitor supports it (72hz is fairly common).

 

[jaypass]

Interesting. I definitely agree that my computer monitor isn't helping things, but I don't think I can change the refresh rate on my iMac. I tried playing back some footage on my HDTV, seemed to look the same.

The only thing is, this doesn't explain why the GH4's judder is so much worse then the AF100(At least to my eyes). That's the part that has me stumped...Shouldn't the judder be pretty much the same at the same frame rate, shutter speed and panning speed? What is the AF doing to smooth that out? Does the OLPF have anything to do with it? Sometimes it seems like the judder is more present in high-detailed areas.

I've also seen some GH4 videos that don't exhibit this judder in situations where I feel like my camera would. What are people doing to get rid of it? High shutter speeds? 60p?

Now that Panny doesn't seem to be upgrading the AF100 at all, I'm trying to rig out the GH4 for use as my main cam, at least until I can budget for a whole new kit with a FS7, c300ii or whatever else comes out in the next year. Hopefully selling my AF100 helps fund that...but this frustrating judder keeps holding me back from committing to the GH4 full time.

 

[Batutta]

Only variables I can think of that might change judder if all other things are equal are compression, and rolling shutter. If the AF-100 has worse rolling shutter than the GH4, that might ironically help reduce judder a tiny bit, but I'm just guessing. Play with shutter speed. Some people like 1/40 on the GH4 vs 1/50. The extra detail in 4k footage might be a factor as well. Did you shoot in 1080p 24p on the GH4 and compare it?

 

[jaypass]

I have tried 1080/24p in the past, and I do think that motion on that looks a little smoother, but not a ton. That's also a much higher bitrate and I-frame which may be helping things.

I used to shoot at 1/40, but now I've been using shutter angle instead of speed and I keep it at 180 degrees. Maybe I'll go back to 1/40, it should be a little smoother.

FWIW, I never experienced this much of an issue on my GH3 either. There's a few other threads out there with the same complaint, so I don't think it's just me that's picking up on it.

http://www.dpreview.com/forums/post/54748072
http://www.eoshd.com/comments/topic/6680-panasonic-gh4-jitters-strobe-effect-when-panning/

I've definitely read more, but that's the first two I could find on google. There's a lot of reasonable explanations out there, from monitor refresh rate to editing software playback issues, maybe even that it's typical 24p motion cadence...but still no explanation for why it's so much more annoying on the GH4 then my other cameras. Nor does it explain why I can find several GH4 clips on Vimeo that look great compared to what I'm getting.

Batutta do you have a GH4? Have you experienced anything like this? Maybe I'll mount my GH4 on top of my AF100 with the same focal length and do a few pans and see how they look side by side. I just want to figure out if what I'm seeing is normal or if I'm going crazy over here.

 

[jaypass]

it the sensor read-out , basically the speed of it. there are no problems with a (say) sony F55 . this is now becoming one of the tools they use to promote faster and way more expensive cameras. then there is also the combination of the frame rates used, for example the ea50 that I had was terrible @24p but less terrible @60p. a smaller sensor (usually) helps as long as they put a decent processor to read it, for example I'm having surprisingly smooth pans with a jvc gy-h200 even at 4K (night and day compared to the jerky pans of the AX100 that I had before).

Gotcha. I've been shooting at 30p more often lately, and that definitely helps. Just wish I could go 24p without having to worry about that judder...I'm probably more sensitive to it now then I ever was before because I'm looking for it on everything, but I've been following the GH4 Vimeo User Group and it seems to be present on a lot of clips there. Not all, but a lot. Maybe the ones that don't have it are using 30p? Who knows.