GH3 GH3 Jitter during pans and other camera moves

E

ericsf

Member
Hey folks,

I have a GH3 coming in the mail and have been watching a lot of GH3 user videos and footage. I've noticed in many videos during pans or slider moves that the motion isn't smooth. Instead there is jitter or stutter in the movement. I've seen some people comment on it in various places but have never seen any explination of why this is happening or solutions. Could it be that the moves are too fast for 24p? Anyone have any insight? This is a pretty major issue if all movement like this turns out jittery.

Here is an example of what I'm talking about. This video is full of jittery slider moves...

www.vimeo.com/60515737
 
Without seeing the original footage, its hard to judge.
From this clip, it looks like it could be a Vimeo compression/playback issue, or perhaps a frame rate conversion issue (slider shots may have been taken at a different fps, perhaps over cranked to give speed options in post?).
 
TheDingo said:
The "pulsing" in the movement makes me wonder about the slider they used. ( it looks too slow to be a camera issue )
Click to expand...

It doesn't look to me that it's a bad or un-smooth slider. There's not uneven acceleration and deceleration. It seems more of a choppiness that feels electronic in nature. I don't know enough to know if it's a frame rate or codec issue or what...
 
kinda looks like longGOP compression issues to me. but i dont think the gh3 uses any longGOP formats...?
 
wgzn said:
kinda looks like longGOP compression issues to me. but i dont think the gh3 uses any longGOP formats...?
Click to expand...

I second that, I don't think it has anything to with the slider movement. I've seen similar issues in footage shot at 24p then slowed down. Vimeo of course never makes footage look any better either.
 
This came up a lot a when the GH2 and the AF100 came out... or at least something similar.

Lots of threads on it and Barry posted quite a few times if I remember.

Gneral consensus (if I remember - I mat be wrong ) was that increased edge detection or contrast between light and dark exaggerated the in-camera processing, ending up with a choppy effect (irrespective of frame rate). I remember an AF100 demo of a slow pan across a window (with dark areas and burnt out glass) and another one that was a GH2 in a sunny street (Europe I thin) that had dark vertical bars in the windows and strobed a bit when the camera was panned over the stone walls surrounding it.

Maybe a thread search is in order... gulp!
 
I shot it in IPB @ 24FPS. I noticed in the more compressed version that there's less jitter. However, best stuff is the lower contrast shots. Moves were a lot smoother there. The jitter appears to be stronger with the higher contrast shots, especially with the skateboards. That tells me that the compression has something to do with it.

I also shot it with a dolly (10-12ft. ish(?)), not a slider.
 
i wonder if it has anything to do with sensor size and the way the camera processes the image? as i seem to recall seeing this kind of thing primarily in apsc and m43 clips than in 5d stuff... just a thought. absolutely no scientific knowledge supporting it.
 
IPB is interframe, ALL-I is intraframe. If you test both you might be able to determine whether it's a codec issue. Another option is to record the 60i to 24p pulldown to a Ninja and see if that affects the cadence. I've heard that the GH3 does have cadence issues but hopefully someone will figure out a workaround.
 
Would the speed of your memory card factor into this? If you're shooting 50mb/s would you need a card that writes faster than that? Getting jitter from a card that's too slow? Sorry if that's a dumb question but memory card speeds and what speed cards cameras actually need have always puzzled me a bit... Panasonic's site says only that the GH3 is compatible with class 10 UHS-I and doesn't specify anything about the handful of diff speeds within that category.
 
heyrobert said:
I shot it in IPB @ 24FPS. I noticed in the more compressed version that there's less jitter. However, best stuff is the lower contrast shots. Moves were a lot smoother there. The jitter appears to be stronger with the higher contrast shots, especially with the skateboards. That tells me that the compression has something to do with it.
Click to expand...

Thanks for chiming in on this. What profile settings did you use? If high contrast seems to make the jitter worse, I wonder if shooting with contrast at -5 would help.
 
I shot it at -2 everything. It seems just like things with high contrast edges hurt it a little more than anything.
 
You must log in or register to reply here.
Back
Top