@LPowell Yes, thanks for that - light strobing's a big one. Another case for 25fps in PAL land as well as shutter considerations. 24fps almost needs another workflow.

@LPowell - then, do you think 1/30 shutter in NTSC land should work more safely given that it is exactly 2x 60Hz ?

I personally am afraid that it will give TOO MUCH of a motion blur though?..

@rozroz "What's the cons of using a 1/40 shutter?"

With on-set lighting, there's always the risk of getting strobing effects when shooting at a shutter speed that doesn't match the power line frequency, i.e. 1/60 in NTSC 60hz regions, or 1/50 in PAL 50hz regions.

Here's a simple A/B test.

The original GH2 footage which I thought exhibited unpleasant strobo effect, has been treated with CC Force Motion Blur in AE.

I then labeled original and motion-blurred versions with letters A and B. I then looped the A/B roll six times in the same video, to give the viewer enough time to analyze it.

Now, in which one the motion looks more pleasing, A or B? Just your subjective opinion, please.

(obviously footage is crap, camera was waved around to establish the shot, settings: 14-42mm kit lens at 42mm telephoto, shutter 1/50.)

The file is downloadable here:

https://docs.google.com/open?id=0B8-e5MfdPT29VkkzR2NlMU9PWXc

@mo7ies 2)Shutter speed, which on this camera is not slow enough to produce nice blur even at 1/50 (regular 180deg shutter)

Once again, my own 1/40 shots blur movement nicely so I cannot reproduce the problem. But If you post grabs of the offending stuttering frames, I'm willing to bet they're under-blurred.

Now please everybdy, post just one of these stuttering frames and we can confirm this. If you post two consecutive frames, we can see if the action is close enough for smooth motion or else if somehow a frame has been doubled or missed (another, rare problem).

The story of the rolling shutter may hold true, but hey, if it's blurred movement, I could squeeze a blurry Bugs Bunny into that moving sequence and you'd you'd never know. [except by osmosis - you wake up longing to chew on a carrot]

@mo7ies I meant not just pans. Anything that moves in the frame

Yes, of course; failure to motion-blur prevents us from using a whole armoury of film making techniques including the one where a bus sweeps across the entire frame, the fun, zip-pan accompanied by that "whoosh" sound -and more. If you shoot everything at 1/30 you'll also end up blurring shots you want to show only slight movement in. 1/40 is considered normal and is what almost all films use. (When Bolex Reflex came out with a variable shutter it was mainly for sport & scientific purposes). You've shown how we can salvage short stuttering sequences in post by painstakingly applying motion-blur. So a worst-case scenario might be that we keep the shutter on 1/40 whenever shooting at 24 fps and live with it. Let's hope we can find a better solution.

Here is an interesting article about all this: http://nofilmschool.com/2011/06/tessives-time-filter-brings-films-dreamy/

@yeehaanow

Since it scans from the top down, the bottom image gets skewed  . . .

Relative to what you’re viewing on the screen, it’s the other way around—bottom up.

My theory is that it's due to rolling shutter. At 24p it takes about 25ms to scan the frame, which is the same speed as a 1/40 shutter. Since it scans from the top down, the bottom image gets skewed and then the next frame "jumps" at the top relative to where the bottom of the previous frame was. Subtle, but there.

@Roberto >> Sorry, only see nice, smooth motion-blurring with f8.0, 160 ISO 30 shutter

I chickened out and didn't go as slow as 1/30 shutter. I started with the "proper 180 deg" 1/50 shutter, then backed down to 1/40 and that seemed to help smoothing out the motion a bit.

By the way. By strobing/stuttering I meant not just pans. Anything that moves in the frame, produces the same unpleasant/unwatchable effect with GH2 - apparently more so than with other cams. Think wide outdoor shot of a street, with a person walking at normal speed. Major strobing on that person!

I gather 1/30 shutter would help even further! I just didn't try it yet. And of course it'd also help with light sensitivity indoors with slow lenses, exposing GH2's sensor to even more light.

So can we say that two major contributing factors to the exacerbated stuttering on GH2 are:

1. Scenes with High-contrast edges and
2. Shutter speed, which on this camera is not slow enough to produce nice blur even at 1/50 (regular 180deg shutter)

1) may not be avoidable/controllable, but 2) by dropping shutter speed to 1/30 we may re-gain the pleasant motion blur with GH2.

Is this a current consensus?

@Roberto

If that screen-grab is grabbed from the middle of the strobing/judder you mention, I’m not surprised; it should be blurred.

This is frame #1 out of 168 frames while the columns are in the filed of view. The pan is fairly even, and each frame has approximately the same amount of blur as the one I posted.

Perhaps I wasn’t clear enough in the post. My point was that strobing and judder are not something unique to the GH2 as some people seem to suggest, but rather the inherent artifacts created by the 180º shutter, 24fps, and faster-than-recommended pan speeds. It’s true that while it’s not always an easy process, one can change the shutter angle in a film camera. I have no information whether it was the case for that particular scene in Life of Brian, but I think it’s a safe bet to say they shot at 24/180.

@mo7ies OK, re-formatted fast SD card and installed Sanity 4.1 to match your settings (and eliminate the artefact red-herring problem) Sorry, only see nice, smooth motion-blurring with f8.0, 160 ISO 30 shutter, Nostalgic and 14mm pancake. Nice blurring = smooth playback. @Rambo - I'm not sure what @Lpowell was specifically referring to - but at present @mo7ies seems to have cured stuttering with motion-blur in post. So I'm personally looking for under-blurred frames which would cause stuttering. @Mr_Moore - If that screen-grab is grabbed from the middle of the strobing/judder you mention, I'm not surprised; it should be blurred. I sometimes find it hard to make sure the GH2 shutter stays locked on the "normal" (180 deg) setting. If it were somehow slipping into high shutter speed, that would be a simple reason!