DV Info Net

DV Info Net (https://www.dvinfo.net/forum/)
-   Canon XL and GL Series DV Camcorders (https://www.dvinfo.net/forum/canon-xl-gl-series-dv-camcorders/)
-   -   What would cause this? (https://www.dvinfo.net/forum/canon-xl-gl-series-dv-camcorders/78549-what-would-cause.html)

Mike Andrade October 30th, 2006 08:48 PM

What would cause this?
 
1 Attachment(s)
I shot this a few weeks back in overcast conditions and most of the footage looks great except for these sailboats. The colors, especially red and blue seem to bleed into each other. What ever is going on here is noticeable on a CRT monitor as well as on my computers flatscreen monitor. I was at full focus on the 20x lens and shot it at 30p, 1/30th shutter speed. The boats were traveling at a high rate of speed. I tried a color smoothing filter in FCP which helped about 20% or so but nothing significant. The screen grab did loose some quality when transfered to Jpeg to post on here. Any help or insight would be greatly appreciated, I'm still a little green with the XL2. Thanks

Mike

Justine Haupt October 30th, 2006 09:06 PM

What you have there is color artifacting specific to DV25 (miniDV) footage. It has to do with the fact that the XL2 (and all miniDV cameras) actually capture color data at a much lower resolution than luminance data. Normally this isn't norticeable, but the primary colors (red especially) bring out this awful artifacting.

There's not too much you can do in-camera (that I know of) to reduce the effect besides perhaps turning down the color gain for the problem color. It's the color that's causing the problem, not something set wrong in the camera.

BUT, In post, Magic Bullet has a great tool that quickly and easily completely fixes this problem -- you can shoot bright primary colors all you want and not have to worry about that "blocky-bleeding" look. Unfortunately, MB is expensive, and I don't know what other programs have a de-artifacting tool. I'm unfamiliar with Final Cut (besides the basics), so for all I know, there might be something already built into it... maybe someone else could comment.

In any case, you either have to fix it in post or avoid those colors. This is also the reason people say you must be especially careful when lighting a green/blue screen when shooting miniDV.

Mike Andrade October 30th, 2006 11:37 PM

Thanks alot for your explanation Justin. I shot about 15 different sails that day and I was stumped why this color combination was the only one with those artifacts. I've been looking for an excuse to pick up Magic Bullet anyway. Thanks again.

Mike

Tony Davies-Patrick October 31st, 2006 04:30 AM

Another thing that adds to the problem is that colour fringing increases with certain subjects and light conditions when the 20X lens is used at the extreme telephoto end.

Jarrod Whaley October 31st, 2006 10:18 AM

I just wanted to chime in here that Magic Bullet's deartifactor will not do anything different than the chroma blur you say you've already tried, nor will it do any better at cleaning up these chroma problems you're having.

"Deartifactor" is a very misleading name. Chroma blur is all it is. And in fact, you can only choose one preset amount of blur for DV. One. And the amount of blur is very slight.

I don't know for certain about other NLE's, but Vegas has a chroma blur that works better than MB's deartifactor, and gives you more control.

Mike, I just thought maybe this info would stop you from buying Magic Bullet when all it will give you is things you already have, and throw in obscene render times with no real benefit. :) Magic Bullet's only real benefit to anyone is the deinterlacing and frame-rate conversion it does. Since you have an XL2, you don't need that. And everything else that MB does can be done just as well (and in some cases better) with your NLE.

So why pay a few hundred bucks for what essentially boils down to absurdly long render times? :)

Justine Haupt October 31st, 2006 11:23 AM

Jarrod, I didn't realize it was nothing more than chroma blur -- and I use Vegas!

But, on the rest of what you said about MB, I have to disagree. I just recently tried MB, and it can create looks that for the life of me I cannot reproduce with Vegas alone -- that's using every which combination of "color corrector", "secondary color corrector", "color curves", "HSL adjest", "Brightness and Contrast"... etc etc. MB has adjustments for which an analogue just doesn't exist in Vegas. Before I tried it I was of the same opinion (that it was nothing special), but I have been converted!

Mike Andrade October 31st, 2006 12:13 PM

Thanks for you insight as well Jarrod. You make a good point. I have seen some great results that have come out of Magic Bullet and a director I am working with now swears by it, but I have heard about the render time issues. Since it is just chroma blur, I will just try to work around it and as Tony said just stay away from the extreme end of the 20x. Thank you all for responding and helping me with this.

Mike

Adam Bray November 1st, 2006 06:42 PM

I'm no expert, and am still learning myself. But doesn't 1/30th shutter seem too low to be shooting objects moving at high speed? My understanding is higher speed = higher shutter. I don't shoot anything under 1/60 unless I'm trying to get blur.

Jimmy McKenzie November 1st, 2006 07:17 PM

Quote:

Originally Posted by Adam Bray
I'm no expert, and am still learning myself. But doesn't 1/30th shutter seem too low to be shooting objects moving at high speed? My understanding is higher speed = higher shutter. I don't shoot anything under 1/60 unless I'm trying to get blur.

The above is bang on.

I know you can't un-ring the bell and go and re-shoot the subject, but big contrast of luminance and colour can introduce these conditions as you have discovered. If this were a different camera manufacturer (name withheld to avoid the ensuing flame-wars) some might say it was chromatic aberration. But it's not.

-3db with pressed blacks and a muted colour set in custom presets might have saved this fiery conflict but that is Monday morning quarterbacking ... to test the infinite permutations on the fly is impossible.

The shot does show a unique colour contrast not found very often when shooting outdoors... nice.

Jarrod Whaley November 2nd, 2006 11:13 AM

Quote:

Originally Posted by Justin Haupt
I just recently tried MB, and it can create looks that for the life of me I cannot reproduce with Vegas alone

If you can't figure out how to do it, does it mean it can't be done? :)

You could be right of course, but I never saw anything in MB that I thought was impossible (or even difficult) to do with other effects. And as soon as I tried to render something and realized it would take 9 years, I decided it wasn't for me. :)

Richard Hunter November 2nd, 2006 06:25 PM

Hi Jarrod. Agree with your sentiments about the MB render time, but there is another solution.

If the footage is already progressive, you don't need the deinterlace function of the MB full version, so you can use MB Editors Edition (plugin for Vegas) to get the same kind of appearance to the image. What's good about Editors is that it will play and render in realtime with certain Nvdia graphics cards, as it uses hardware acceleration. I use this a lot and am very happy with it.

Richard

Jarrod Whaley November 2nd, 2006 08:25 PM

Quote:

Originally Posted by Richard Hunter
Hi Jarrod. Agree with your sentiments about the MB render time, but there is another solution.

If the footage is already progressive, you don't need the deinterlace function of the MB full version, so you can use MB Editors Edition (plugin for Vegas) to get the same kind of appearance to the image. What's good about Editors is that it will play and render in realtime with certain Nvdia graphics cards, as it uses hardware acceleration. I use this a lot and am very happy with it.

Wait, are you talking about real-time preview or rendering to a file? Preview is fine (OK, maybe a bit slow), but when you render out to .avi, it takes 75 days. :)

I apparently don't have a card with which MB will render in real time. Anyway, as I said, I can do all of the same things with Vegas anyway.

Richard Hunter November 3rd, 2006 10:41 PM

Hi Jarrod. It's both preview and rendering, but it only works with Editors Edition or MB Suite V2.1, not with the plugin that comes with Vegas.

If your graphics card is one of the "chosen" then the MB effects render faster than the Vegas filters, which is why it is so attractive. It's not cheap though, especially if you need to replace your graphics card to get the hardware acceleration.

Richard


All times are GMT -6. The time now is 08:49 AM.

DV Info Net -- Real Names, Real People, Real Info!
1998-2021 The Digital Video Information Network