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-   -   DOF (In Post) Experiment.... (https://www.dvinfo.net/forum/techniques-independent-production/40488-dof-post-experiment.html)

Matthew Cherry March 3rd, 2005 11:03 PM

DOF (In Post) Experiment....
 
Alright guys, again I'm going to ask for your help. I'm trying to fake 35mm depth of field in post. I started with the easiest clip (no idea how I'm going to do it to all of them yet, but I'm trying to see if this is possible.

Now, I've stripped away ALL color correction so this is raw footage, done so that you can see the DOF effect better. The compression (Sorensen 3) affects it somewhat but not so much that you cant see the effect and, I hope, judge it for realism. The clip is 3.5 meg so it shouldn't be too much of a strain.

http://www.birthofthecool.com/Testing/dof_test.mov

Please let me know what you think, and if it sucks, why so.

Matt

Glenn Chan March 3rd, 2005 11:25 PM

Well since you mentioned it I looked for the fake DOF not working properly and know what to look for. If you look at the cabinet right by the edge of his face you'll see it's not blurred, which is what happens when you try to mask things.

If I were watching it without knowing fake DOF was applied, I probably wouldn't notice it.

Alternate ways to draw attention to the guys face would be:
A- Add vignetting... i.e. a mild black gradient from left to right. The black matte generator and the masking tools in Vegas is one way to do it.

B- Make the blurring drop off as it gets nearer the guy's face. That isn't quite the same though.

C- If the colors are different enough, you can use secondary color correction to punch away everything except for the guy's face. I'm not sure if it can be done in this scene, you have to very carefully limit things by color and luminance. Brown is a dark shade of orange/flesh tones.

Cosmin Rotaru March 7th, 2005 11:02 AM

You told me about it and I knew where to look, as Glenn also mentioned.

Otherwise, I would have not know! Great job, I'd say! :)

Dave Ferdinand March 7th, 2005 01:49 PM

It works for very specific situations. If you have a pan or tracking shot, that would make things very hard.

But I doubt that in the middle of a movie many people would notice it was done in post, so for this case works quite well.

Matthew Cherry March 7th, 2005 03:41 PM

Well, It's getting better. Right now I'm experimenting with using a b-spline mask in Motion and keyframing the mask to move with the subject. Pans without people movement are actually very easy to do like this. It's people movement that is difficult, but I'm getting MUCH better results this way. Will post a new clip soon - well as soon as I can figure it all out.

Matt

Mike Hardcastle March 7th, 2005 03:49 PM

great effect matt, whats the basic proceedure for doing this...???

John Threat March 10th, 2005 01:32 PM

It did look good!

That shot looked like it would have been easier to pull off an in camera shallow DOF. But the option to do it in post looks good.

Matthew Cherry March 14th, 2005 04:26 PM

Thanks guys, I'm shooting, arranging locations and doing some basic editing at night (all while holding down my day gig) so I forgot to respond.

The basic premise is to create shallow DOF in post that resembles that of film (assuming you couldn't/didn't get it in camera). So I started the experiment (that you saw) by bringing the sequence into Motion (or AE). I had taken a frame grab from that sequence and worked with it in photoshop to extend the hutch and get rid of the actor. Then I blurred the image. The problem was to make the focus fall off in a realistic manner. So I first drew a line of perspective for the shot, this was basically a line from the lower right hand corner to the upper left hand corner. I then cut the image up into diagonally striped sections moving along that line. I then applied a gaussian blur to each section, making it more blurred for each further section. I feathered these sections together so that the effect was seamless and that was it. I then brought that into motion and layered the rough mask of the actor over it.

What I'm doing now is similiar, except instead of using a still (different shot) I'm creating bezier masks for the background and applying affects to the masks that I then animate to move with the shot - in this case a dolly tracking shot. We'll see, so far it's not to bad, but it still needs some tweaking.

Matt

Cosmin Rotaru March 15th, 2005 02:56 AM

I tried a small app once, it was freeware. What it did: take to layers of video - one with the background alone, the second with the actor on the background. Then, it would substract the first video from the second to leave the actor without background. Kind of green screen but without the green screen! :)
Now you have a video with the background (that you could blur or whatever...) and another video with the actor alone.

Of course, the scene should be static and nothing should move in the background...

Jose di Cani March 15th, 2005 04:54 AM

ost some more videos but with more action. for instance 5 character walking to a school or something. A moving shot would be cool as well. Lots of detail in the background.

nice video

chich cam did you use>?|

Adam Burtle March 15th, 2005 07:19 AM

It's late and i'm bored, so i captured a couple of screenshots from a promo piece i'm working on. The darker more 'contrasty' areas are after fake-dof and basic color correction (final color grading will be applied after the piece is approved)..

For those at work, i should note, the 2nd image has a girl in her underwear/bikini.

http://www.adamgeek.com/dvinfo_dof1.jpg
http://www.adamgeek.com/dvinfo_dof2.jpg



<<<-- Originally posted by Mike Hardcastle : great effect matt, whats the basic proceedure for doing this...??? -->>>

the procedure is basically rotoscoping.. you can search google for many tutorials. i'm not sure what he is using to do this in, but after effects / combustion would be the usual choice.

Brandon Greenlee March 15th, 2005 09:47 AM

<<<-- Originally posted by Cosmin Rotaru : I tried a small app once, it was freeware. What it did: take to layers of video - one with the background alone, the second with the actor on the background. Then, it would substract the first video from the second to leave the actor without background. Kind of green screen but without the green screen! :)
Now you have a video with the background (that you could blur or whatever...) and another video with the actor alone.

Of course, the scene should be static and nothing should move in the background... -->>>


You wouldn't happen to remember the name of this program would you?

I could use this in a project I'm currently working on.

Thanks.

Cosmin Rotaru March 15th, 2005 09:52 AM

I'll search it when I get home. I don't even remeber its name...
I'll let you know tomorow.

Matthew Cherry March 15th, 2005 10:20 AM

Please, please, if you could find this program it would make my life SOOO much easier!!!!

Adam Burtle March 15th, 2005 11:43 PM

<<<-- Originally posted by Matthew Cherry : Please, please, if you could find this program it would make my life SOOO much easier!!!! -->>>

if your goal is simply to blur the background on a fixed shot where you can control the background behind the subject.. rather than find a plugin or program to do this, why not just shoot the interview in front of greenscreen anyway. a piece of 3'x3' posterboard would work fine, since you really only have to cover the area of the frame around the subject's head/torso. then shoot a 2nd static shot lit the same without the subject in it, chromakey out the posterboard, and composite the matte over the 2nd static shot. with pratice i'm sure you could produce good results. 'course.. if you've already shot the pieces you need and you can't reshoot them, my suggestions don't help much.


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