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Areas of foliage, gravel etc. causing shimmering, flickering on video?

Often when I video scenes containing areas of fine detail like foliage and gravel in sunny weather I get an unpleasant shimmering/flickering effect.


I assume that this is some kind of moire effect caused by thousands of moving pinpoints of light reflecting from the leaves etc. and not a fault in my camera/TV/editing setup.


Has anyone else experienced this effect under such circumstances and more importantly has a cure been found as it is likely to ruin many scenes shot in sunny countryside settings?


This appears on 1080p/1080i footage shot on my 3 chip Panasonic camcorder, Sony DSLR and Nikon Superzoom "Bridge" camera.

OS X Yosemite (10.10.3), Mac mini i5 2.5GHz & iMac FCP X

Posted on Sep 3, 2015 2:44 AM

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Posted on Sep 3, 2015 8:04 AM

Seems to me it's a result of camera's auto-mode or semi-auto. if you take manual mode I guess you'll get rid of it

16 replies

Sep 3, 2015 9:20 AM in response to Ian R. Brown

Aliasing is different from compression artifacts (blocking or quantizing) and HD is notorious for capturing and displaying detail no one ever really wanted to see. [See the anecdotal references from the old ABC primetime show "Housewives" (not the reality show). When they converted from SD to HD the actresses freaked out over their makeup jobs.]


Russ's references are great but the question is where are you seeing this artifact? Preview? Edit output? From a DVD? BluRay? IN the camera's viewfinder?

Sep 3, 2015 10:44 AM in response to David Bogie Chq-1

Very visible when camera is plugged straight into 40" HDTV to play the raw footage, during full-screen editing in FCP X and also when it is exported as AVCHD mp4 and played on the aforementioned TV.


Hardly visible when played at around 50% during editing.


For anyone interested you can download a 20 second example here:


https://www.btcloud.bt.com/?shareObject=228fad72-ccd4-6948-4c0e-29790d08e598


The clips were shot handheld from my bedroom on a Nikon P530 superzoom camera.


The lens was at 50mm equivalent for the first scene and 800mm and 1,000mm for the subsequent two.


It needs viewing on a TV to get the full shimmer effect.


The extreme telephoto and shakiness may be contributing but I usually get the problem with other cameras in rock-solid wideangle shots.

Sep 3, 2015 11:11 AM in response to Ian R. Brown

Particularly in the first (50mm) clip there are several apparently wild fluctuations in exposure but only in the tree foliage etc. . . . . there is no variation in the brightness of the sky.


There is also a tendency to move quickly and briefly out of focus. This may be exacerbating the shimmer but I have also seen the shimmer on shots which remain perfectly in focus on other cameras.


I must stress that it is more obvious on a TV rather than an iMac screen.

Sep 3, 2015 11:34 AM in response to Luis Sequeira1

I'm gradually coming round to that conclusion too!


On the odd occasion it has happened with my Panasonic SD800, I have not investigated quite as thoroughly as I have today.


Luckily I bought the Nikon for its still photo taking capabilities and not its video!


I'm also wondering whether the brief drifting out of focus could be caused because the camera video is set to "Full-time AF" . . . maybe if I change it to "Single AF" it will lock the focus.


Unfortunately it's now night-time so I will have to wait until tomorrow to test out that theory.

Sep 3, 2015 11:25 PM in response to Ian R. Brown

There's very little you can do against moiré:

• avoid static tiny structures in picture (no 'salt'n pepper jackets')

• zoom a few millimeters in, or out: due to the nature of moiré, you can make it vanish, prob: often the lil' monitors at the cams don't show so much detail ... got a Liliput-TFT in a garagesale, for 70€, which has 'native' 1920x1080 .... and another ton of equipment 😉

• in post: try to add 'grain' to clip …

• mask out the part of the frame (SliceX to meniton here ..., these 'auto-tracking' in coremelts products is plain perplexing "how does a machine

know what I want to mask??") and blur it a few nano-percent...

Sep 4, 2015 2:50 AM in response to Alchroma

Houston, we have positive results!


Tested on tripod with OIS turned both ON and OFF.


Under extremely close scrutiny of TV screen only the barest hint of shimmer was detected which means that to all normal intents and purposes it has been eliminated.


I could not detect any difference whether the OIS was ON or OFF.


So there are 2 "cures" which both need applying:-


1. Turn Autofocus to Single instead of Full-time. (In Movie mode on this camera the autofocus can't be turned off)


2. Use a tripod!


Unfortunately it is not always practical to use a tripod so I will have to endure a certain amount of shimmer occasionally.


I have seen this effect on other peoples' video (plus my other cameras) so it must happen to everyone given the right (or wrong!) circumstances.


It appears that there are 2 causes of the shimmer, both involving the movement of the leaves etc. One is the actual motion of the leaves themselves in a breeze and the second is the slight movement of a handheld camera.


Nothing can be done about the former without divine intervention.

Areas of foliage, gravel etc. causing shimmering, flickering on video?

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