Best settings for green screen work

Richard Allen Crook

Richard Allen Crook

Well-known member
I shot a green screen subject with a relatively flat setting and was told by the post house that it was a nightmare to work with. They blamed the avchd, talking about pixelation and artifacting. This was a surprise, though I think it would have to do more with the settings rather than the codec. Any suggestions on the best practices for using the fs100 for greenscreen work? Or do i need to rent a different camera for this? Thanks in advance for any help!
 
They must not know how to pull a chroma key or not have a very good keyer. I'm shooting an independent movie with the FS100. One of the shots we had to do was a green screen shot of a couple walking out of a trailer door. Because of schedules, etc. I had to shoot at a certain time of day. Half of the green screen was in shade and the other half was in full sunlight on a sunny day. I used Optic Green Tempo fabric from the Rag Place. I raised the Black Gamma as much as I could to preserve shadow detail.

Granted, with most keyers this would be a bit of work. I just pulled a test key with the new Primatte 5 keyer and eyeon's Fusion 6.3 and really had no problem.

If you can post a decent quality still I'm sure others can give you their opinion.
 
Fusion's keyer is great ( as is my fav, Nuke's IBK) but if you have detail finer than the compression artifacts then there's really no way to pull a clean key - the compression artifacts are going to mean roto

An outboard recorder like the BDM would be a good option for the next go-around, picture profiles are a seperate issue.

d
 
I second this, go for a Ninja external recorder at least (422 and mild compression) for any serious green screen work. The post house is right: AVCHD is a nightmare for green screen!
 
Okay, I'll get an external recorder and run some tests. Makes sense...recording at least 4:2:2 and uncompressed *should* do the trick.
 
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I just shot 2 days of green screen for new balance this week. We tested first day. After lighting we shot a strip test and I went back with the editor to check it. It took him about 2 min to pull the matte with no plug ins- just straight FCP. he actually was surprised and mentioned it as being a remarkably clean pull. yes, I think the lighting was part of it- but the camera has to be ok too. admittedly this was not a difficult shot just 4 actors and simple blocking.

For settings I had DL'd the ab settings but after looking at all of them went with my own. That's why their mine. I like the way they look dammit ;)
 
Caleb;

as long as you don't have detail finer than the compression artifacts, or the deliverable is unable to support higher resolution than the compression artifacts.. you're golden
BUT
the second you need more, the compositor is in a world of hurt... when the compositor said compression artifacts were an issue, i would take them at their word
Really has zero to do with the ablity to pull a key, has everything to so with the finite limits of the key edges, no keyer can pull a matte finer than the compression artifacts, that's the finite upper limit - there's no more data to work with

- Even the best keyers (Like Fusion6, Nuke IBK, Discreet master Keyer, DS 3D keyer) you just can't get blood from a stone.
- If you can't get a key without ripping edges or softening and erroding to kill it when there is no more data to work with - then you are rotoing...
- if your deliverables are incappable of resolving such detail, or if the subject does not have such fine detail to start with then you got a free pass this time, does not mean that the next time the free pass will still be on the table.

FCP's keyers are not considered top tier at the best of times, makes me think that comparing your experience with Richard's may not be apple to apples, his crew may be working at a higher resoultion, with fine detail..

I would still opt to use an external recorder if i had any doubt, i would trust the compostor's notes, they did not say they had an issue with the key, they said they had an issue with compression artifacts... they are related, but really are not the same.

d
 
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Dermot I do take the compositor at his word- really ; )

I'm just pointing out that my green screen experience this week was a good one. The compositor i was working with commented favorably on the ease of pull/clean look. I think i mentioned it was a simple set up. Like anything -your mileage may vary.

You know- a few threads about an "issue", alarms go off and next thing producers are telling me they'd rather not use the FS100 for greenscreen. Just keeping it real. balance is good. I had a great greenscreen experience with happy clients this week so the FS100 CAN make a superb compositing solution.

I'm still interested in the settings discussion. I went with my own and they worked but someone mentioned boosting black levels - I assume for edge detail but I dislike a heavy look with shortened grayscale. I'm sure it need not be extreme but I'm looking for more on this - just to educate myself. My settings were custom Cinematone 1. black level "0" gamma "high" and knee manual at 95, slope -1.
 
I'm going to pull the trigger on the Atomos Ninja. Can't wait to do some testing, not only on chroma keying, but also see how well uncompressed holds up to grading vs. the AVCHD.

Any suggestions as to best practices for using this unit during shooting? Also, I understand it requires pull down removal in post. I use Premiere, can't I correct this within the nle? Any help on workflow would be fantastic. :)
 
The Atmos folks recomended a Samuri + the external pulldown removal box (not shipping yet)... it has either;
HDMI in/SDI out -or- SDI in/HDMI out no option for HDMI in/out

at about the same total price is the Pix220

and maybe a bit cheaper is using a BMD as HDSDI-> HDMI converter;
Camera HDMI-> pulldown removal SDI -> BMD HDMI-> Ninja...
advantage is a free uncompressed recorder in the chain
disadvantage is a mess-0-cabelage & power & gak on the rails & trouble shooting when it all goes sideways

makes the 220 seem like it's worth a carefull look

hopefully Atmos folks get it together and make us a HDMI -> HDMI pulldown removal box...

d
 
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