Premiere / Green Screen

Dan7312

I'm tryuing out green screen video for the first time with my 7D. I'm using premiere and it's Ultra Key effect to mask out the green screen. Any hints that might improve it would be appreciated. The vid shows the masked image on a white background and then the unmasked image.


http://www.danalphotos.com/Other/Stuff/9223982_trW3HW#!i=1763832916&k=KFbPN2H&lb=1&s=A

One of the things I think will help will be to comb my hair:D and not wear a fuzzy sweater. My guess is more uniform lighting on the screen would help too, but I'm limited in what I can do there.

The UltraKey effect has number of settings that I think might make sense to someone who really does video editing... I just poked around at them to fix up some issues I had in the shadowy areas. Also I found that picking up the color from a darker part of the screen worked better.

I think I understand some of the settings but what they actually do doesn't seem to be documented. Hints as to what they are supposed to do would be appreciated...

Is there a standard HSB color setting for a green screen or is that important? It's a Matthews screen so I'm pretty sure it's reasonable quality.

In Matte Generation there is a Pedistal setting, what's that? There is also a tolerance which I think for the color?? I'm assuming that the other settings here (like Transparency, Highlight, Shadow, and Tolerance) have to do with how intense, for want of a better word, the matte is.

In Matte Cleanup there is a Choke setting, what's that?. I'm assuming that the other setting here (Soften, Contrast, and Mid Point) have to do with what the control sees as being the green screen.

Thanks in advance for any help!

Dan7312

So I've changed from using the UltraKey to using the ChromaKey and that seems to work a lot better or at least I'm having an easier time figuring out the settings. I guess that rates a duh! 'cause green screens are what what a chroma key is made for.

Dan7312 wrote: »

I'm tryuing out green screen video for the first time with my 7D. I'm using premiere and it's Ultra Key effect to mask out the green screen. Any hints that might improve it would be appreciated. The vid shows the masked image on a white background and then the unmasked image.

DavidTO

Glad you figured it out!

DavidTO

I'm not positive, but I believe:

Pedestal=Threshold

and

Choke=Tolerance.

Rob Pauza

Hi Dan,

I'm seeing shadows on the green screen. Looks like your subject is too close to it. Try distancing your subject from it by at least 6 feet, more if you can. You'll want that screen lit separately from the subject and as evenly as possible.... using as little light as you can to do so. (Too much light on the screen will turn it into a light source that your studio walls/ceiling will bounce around and ultimately put green back onto your subject) Flag any light walls with black fabric if needed to reduce this bouncing effect. The screen should roughly be 1 stop under the subject for best results. Steaming out the fold lines in the fabric will help too. Lighting is the key. (no pun intended)

As far as software goes, I'm only familiar with Keylight. Generally though, you'll run whatever flavor of chroma key software you're using, then hit it with a layer or two of spill suppression.

Forgive me for asking, but if you're wanting a white background, why not just shoot with a white background?

-Rob

Dan7312

Thanks for the info, esp. the part about not being too close to the screen and the 1 stop diff. I figured light was a big issue and I guess I have to look at this as a change to learn more about it:D

I'm making an instructional video and the background is going to be creatred separately... basically there will be diagrams and text appearing on it as I talk.

I don't have an actual studio, I work out of my house... I've been making instruction vids for about 5 years now, and I want to try something different. I think this counts for that

Rob Pauza wrote: »

Hi Dan,

I'm seeing shadows on the green screen. Looks like your subject is too close to it. Try distancing your subject from it by at least 6 feet, more if you can. You'll want that screen lit separately from the subject and as evenly as possible.... using as little light as you can to do so. (Too much light on the screen will turn it into a light source that your studio walls/ceiling will bounce around and ultimately put green back onto your subject) Flag any light walls with black fabric if needed to reduce this bouncing effect. The screen should roughly be 1 stop under the subject for best results. Steaming out the fold lines in the fabric will help too. Lighting is the key. (no pun intended)

Forgive me for asking, but if you're wanting a white background, why not just shoot with a white background?

-Rob

Rob Pauza

No prob. I'm hardly a green screen pro myself, but hopefully that will help. Let us know how it turns out.

-Rob

Rob Pauza

Any luck Dan? I had to setup lighting for a green screen yesterday for still photography and thought of you.

-Rob

Dan7312

Here is the setup http://www.danalphotos.com/Other/Green-Screen/22142943_dx4M5H A part of the results are there too.

I've learned a lot doing this. I think the results I got were acceptable but not great. The color is not good, but I've finally figured out what I did wrong and I'm not very good a correcting color in general and certainly not in Premiere. There was plenty of room to leave a gray card in the frame for the whole shot and next time I'll do that.

I did the audio with a little Tascam DLT recorder. I also recorded the audio on the 7D, and sync'd the tascam results to it. It's still a bit echo-y, but I know I have to set the mic' closer to me. The audio recorded by the 7D was incredily echo-y. Maybe I should invest in a lapel radio mic', some of them look pretty cheap... any ideas of the cheapest ones with reasonable quality? I think I'm going to NY in a few weeks so maybe I'll stop by B&H. The audio room there is pretty incredible as is the tech help they provide.

A couple of things I figured out. Make sure you hair is combed and don't wear a fuzzy sweater before you stand in front of the camera:D Flying hair and fuzz seems to raze havoc with the green screen. Maybe next time I should get a stylist and an MU....

Your suggestion of moving away from the green screen was a big help.

Lighting could be a lot better. I don't really have any lighting, just what came into the windows... and was not a bright day. I did manage to get the level diff between parts of the green screen down to about .5 EV. If I had real lights I'm sure I could have done better.

I found that the Premiere Ultra Key was better than the Chroma Key effect. That and a garbage matte and I was able to get rid of the background completely.

To sync the audio I started each clip by just clapping some sticks I had laying around together.
and used those peaks are marker to sync things.

Another thing is to make sure you have a mark to stand against so you end up in the same place on each take. There is little bit of gaffers tape on the edge of the pool table I lined my belt buckle up to.

I'm pretty sure next time I'll get better result and it won't take me two day to do the shoot.

BTW, I've found that actors are real primadonnas... that was me in the vid



Thanks again for your pointers.

Rob Pauza wrote: »

Any luck Dan? I had to setup lighting for a green screen yesterday for still photography and thought of you.

-Rob

Rob Pauza

Looks like you pulled it off Dan. Looks good, especially for not having any lights and working with such limited space. There's a pretty apparent color shift where you fade takes right at 1:00 you may want to tweak if you have time. I'm just being picky though. Thanks for sharing.

I'm afraid I don't know much about audio. What little stuff I do on the side, I have a Zoom H4n, a Rode shotgun and a pair of AKG Perception 420's. Not "Pro" by any means, but works pretty well for me. I use my 7d audio to sync audio from the Zoom. I'm still not crazy about Final Cut X, but the automatic audio syncing works great. Otherwise, a clapper... or banging some sticks together does the trick. I used a book one time and it apparently had been laying there for quite a while. When it closed, a dust cloud hit the model right in the face. Worked great for syncing though.

Yes, actors can be a pain. Looks like yours was top notch though.

Here's my go at lighting for strobe photography if you're interested. This was just a quick test since I'd never lit a green screen for strobe lighting. We have a big photo project coming up. I just used the same setup I would for video and it worked great. I used an umbrella for lighting the subject, but you could really use about anything. Also, I have a backlight, which also helps counteract the spill.

Here's a test photo. (I'm using Primatte for Photoshop, but only have the trial on that computer... hence the watermarked squares) The green ball was just for fun. I was curious how it would key.



Here's the setup. I've added notes to what was used. (Sorry, it's really messy and there's lots of extra stuff making it confusing. It was just a quick test and I didn't think to shoot a photo til after I'd moved stuff around) This setup can be used for video as well.



Anyway, glad you got it figured out. Hope you have a great weekend.

-Rob

TylerW

DavidTO wrote: »

I'm not positive, but I believe:

Pedestal=Threshold

and

Choke=Tolerance.

Not quite. Pedestal, along with shadow and contrast allow you to adjust the way the chroma color is keyed out along its tolerance range. Getting a good key out of uneven background lighting means you'll be spending a decent amount of time tweaking with these settings to make sure you're getting rid of all your green, eliminating any halos, and preserving your shadow detail.

Choke allows you to fudge the edge of your key by pushing it into your subject. Sometimes it, with a little bit of softening, solves a lot of problems with a less than ideal key very quickly. Other times it completely bodges fine details, like eyeglass rims and the like.

Dan7312

Thanks Tyler

So if I understand this right when I increase the Pedestal I change how the transition from the edge of the subject out into the green screen is done. When I increase the choke I'm adjusting the how the transition from the edge of the subject to the inside of the subject is done.

I'll have to do some more practicing with the ultra mask to get a better feeling for it.

TylerW wrote: »

Not quite. Pedestal, along with shadow and contrast allow you to adjust the way the chroma color is keyed out along its tolerance range. Getting a good key out of uneven background lighting means you'll be spending a decent amount of time tweaking with these settings to make sure you're getting rid of all your green, eliminating any halos, and preserving your shadow detail.

Choke allows you to fudge the edge of your key by pushing it into your subject. Sometimes it, with a little bit of softening, solves a lot of problems with a less than ideal key very quickly. Other times it completely bodges fine details, like eyeglass rims and the like.