Author Topic: strange artefacts in both .raw/.mlv in any of my shots.  (Read 3036 times)

liok

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strange artefacts in both .raw/.mlv in any of my shots.
« on: November 17, 2014, 02:57:45 PM »
Hi, i've started to shoot with my 60D, trying to see when it's better to shoot in h.264 or in raw.
raw footages are impressive but i get a lot of moire and strange chomatic aberations on nearly every edges.
is it normal to get these ?

the black pixels (with magenta edge around it) are only here in the .mlv files.

I will continue to try to diagnose the problem, I already tried to unable every custom parameters in ML, but if someone has already dealt with this problem it would be awesome as I bought my 60D to make a little short film during my trip in Myanmar in two weeks.
thanks a lot.

liok

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Re: strange artefacts in both .raw/.mlv in any of my shots.
« Reply #1 on: November 17, 2014, 03:34:29 PM »
super strange, the previous images were DNGs imported in Nuke. I've just tried with After effects, and that gives a quite different result:

the chromatic aberation on the edges is 95% gone. it's no more a problem. So it's just the J_Ops plugin that allows nuke to read DNGs and other raw format that's interpreting in a wrong way the files I gess.

dmilligan

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Re: strange artefacts in both .raw/.mlv in any of my shots.
« Reply #2 on: November 17, 2014, 04:24:03 PM »
That's aliasing that's been made worse by using an inferior demosaicing algorithm. After Effects uses ACR for demosaicing which is really good at removing/preventing aliasing artifacts, and that's why it looks better in AE.

The aliasing is made worse by the line skipping the camera does in standard video mode (there's not much that can be done about this), but you can use "crop" mode (just press the zoom in button), which doesn't skip lines and means the aliasing is much better.

liok

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Re: strange artefacts in both .raw/.mlv in any of my shots.
« Reply #3 on: November 19, 2014, 01:08:42 AM »
Oh thanks a lot. I'll take note.
I'm not sure i've understood how to activate the crop mode in ML on the 60D, just have to press zoom+ before pressing record ? isn't that just a display zoom for adjusting the focus manualy ? (these images were raw footage, not standard h.264)
thanks.

dmilligan

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Re: strange artefacts in both .raw/.mlv in any of my shots.
« Reply #4 on: November 19, 2014, 03:03:26 AM »
Pressing the zoom button causes the camera to enter a different video mode where it reads every line of a smaller cropped area of the sensor (instead of the line skipping that's going on in regular video mode). This is how the camera is able to show you a zoomed in LV for focusing (if it used the standard, lower res, line skipping mode when you zoomed in, it wouldn't be much good). ML takes advantage of this and let's you record it.

liok

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Re: strange artefacts in both .raw/.mlv in any of my shots.
« Reply #5 on: November 19, 2014, 06:45:46 PM »
uoh, ok, thanks a lot, I'll try!

puma69

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Re: strange artefacts in both .raw/.mlv in any of my shots.
« Reply #6 on: December 04, 2014, 06:54:16 AM »
.