For chroma key talking head in studio: Auto Iris/aperture or Auto Focus?

[Francis Lee]

When shooting talking heads in the studio with a green screen / chroma key background...

In the past (with another camera) I did a manual white balance and used manual focus... leaving the iris/aperture on auto.

Now we have a Sony NXCAM HXR-NX5U and are about to set it up in our small studio to shoot a bunch of talking heads features in front of a chroma key green screen...

And I just wanted to double check that our procedure of doing a manual white balance and then a manual focus... and leaving the iris /aperture on auto was the way to go.

Thanks for any help.

[Justin Hewitt]

Hi.

I do an internet TV show on Business Intelligence, I was originally using my D800, but then due to a repair issue (it got dropped) had to swap to my NX5U

I do the following:

* Autofocus --- no problems with focus accuracy.
* Manually white balance -- essential
* Edit each clip in Adobe After Effects
* Use Keying 1,2 for convert green screen to transparent.
* Set screen matte to clip blacks to 20 and whites to 70
* Mask around the interview subject to remove any unnecessary green screen artefacts.

** Recently I have added a Ninja 2 to the mix and the output has been significantly better due to the higher bit rate and higher screen colour sampling.

Hope that helps ...

Justin.

[Paul R Johnson]

Sharp focus is the essential thing for good keying, so as long as the lighting and subject placement are fixed, I'd set the aperture and leave it, with focus something to look at continuously if the subject leans in or out, or turns.