Parallax
…achieved by changing a 3D cameras position, the end results through the active camera give you that sense of depth, or perspective. And that movement of objects moving at different rates based up on their z-position, leads to the visual effect that we typically refer to as “parallax.”
Green Screen Workflow Notes
Fun Jargon Folklore
backdrop bar… pony clamp / clip clamp…
cyc wall / cyclorama
a pepper = a tungsten fill return-light so you create a crisp “rim” along the edge of your subject.
then key for the focused direction angle for subject to be iht with like sunlit
One of the great things about film production is the slang, much of which dates back to the early days of Hollywood. Spend enough time on a set, and you’ll hear dozens mysterious terms: jokers, hot bricks, redheads, stingers, sticks, the martini, the Abby Singer, cookies…
My favorite is the slang for a simple wooden clothespin – C-47 (also known as 47’s, CP47’s, bullets, ammo, and pegs).
I was indeed asked for a C-47 on one of my first film shoots (by someone I suspect was just trying to make me look dumb). I spent a solid ten minutes pretending to know what I was looking for before someone finally reached into a cloth bag and pulled out a handful of simple, ordinary clothespins.
The REAL story (at least, the first version I ever heard and my favorite of the bunch) is that back in the early days of Hollywood, studio heads auditing equipment requests from lighting departments would go crazy over the idea of spending good money for something as simple and mundane as clothespins. Hence, “clothespin” was quietly changed to the far more impressive-sounding C-47, and all requests were immediately approved by clueless execs.
One final version: it was actually to avoid the IRS, who would not consider clothespins to be work-related expenses (but had no problem with C-47’s).
LOL – Feeling creative? Flip the spring on a clothespin to turn into a pair of wooden tweezers, and you’ve got a C-74!
Gaffer
a gaffer is essentially a lighting director in film parlance. On a live studio set, you would talk about a lighting director. But on a feature film set or tv set or even a corporate video set, you’re talking about having a gaffer.
what it takes to get professionally lit green screen. So there’s really two separate lights – you have two distinct sets when you’re shooting green screen. First, and most important really, is to ensure that your green screen is evenly lit as possible and lit to a level at which the editor can do his work or her work on the back end to ensure that it’s a very seamless appearance between the model and the green screen itself, or the keyed-in background.
– And in that case, we’re going to use usually things like a kino flo light or a really broad light – as a gaffer, even as a shooter yourself, you need to employ the lighting yourself. You need to think in terms of as broad a source as possible. If you can imagine the sun lighting a green screen, there’s no down light on that green screen. It’s a perfectly even light. Since we don’t have that sun at our disposal all the time, we’re employing tungsten lights and kino flo fluorescent lights, LED panels, and so forth, to try to create an even spread of light.
And often that means using as broad a source as possible. You want to have as large an effective size of light as you can get to light that green screen without any drop off. – And sometimes what people will do is also use soft boxes or other diffusion elements. But since the green screen needs relative, intense light, a broader source is generally a good idea. – Aiming a fresnel light at a green screen, for instance, without any diffusion of any kind on it, would be a mistake. Simply put, you would an area of light, of heat, and then a drop off in that light source, which really makes the job of the editor almost impossible.
You can certainly use a fresnel, they’re perfectly reasonable lights to use. However, in doing so, it really is important to separate away from the lights some sort of diffuse source so that you’re filling again with a very soft light on the green screen. – And once that background is lit, we then have to move on to the foreground, lighting our subject, or perhaps multiple subjects.
Shutter speed
for DSLR 1/50fps … 1/125 slow motion
affects motion blur and darkens exposure the greater framerate
slower fps allows more light to sensor to blow things out
** higher frame rate = Do it handheld ! for dynamic effect
ISO
expsoure index
ISO 500 high blownout…
less noise in ISO 320 than ISO 200
bumping up ISO adds noise
adjusting ISO is dangerous
dont let anything ZEBRA — cant revover from damaged highlights and blooming
if you raise ISO colors de-saturate.
know device native ISO…
**** ENABLE Highlight Tone Priority Mode *****
… SENSOR SIZE ::
Canon 5D wider sensor than canon 7D
White Balance
pedestal CUSTOM White Balance
determine dominate hottest white
place gray card in that
take a photo
and
calibrate on that photo…
NEED a Gray card
Grey/White Balance Card 18% Gray DSLR Camera Custom Color Calibration Board 12″ ~ $10 ebay
PULL FOCUS
zoom in and rack focus then zoom back out
Shadows
… I know one of my pet peeves, during editing, is dealing with shadows.
– Shadows can be problematic, obviously. Not actually having a key source match the lighting on set is another problem. It really is important to understand, as a gaffer, what it is that the director, director of photography, that the production company has in mind for this shot after the fact. If you’re in a corporate board room and you have a small green screen set up, and the plan is to simply have someone pegged in front of an exterior window, or something along those lines, understand that.
Understand where the light source is going to come from. And that really will dictate how you light that person. You need to be aware of color temperature, whether you’re using warm lights or cool lights. You need to be aware of the type of light, whether it needs to do something hot. For instance, on us we have a nice, soft, wrap light. That doesn’t make any sense if you’re shooting something that is going to be keyed into a background that is really hot sunlight. All these things need to be taken into consideration when we’re determining how we’re going to light our subject. – And I think if somebody already has experience lighting interviews, that translates pretty well to lighting the subject for green screen…
Simply put, the rules are the same. Lighting a green screen doesn’t mean we have to throw everything out that we know about lighting. You still need to understand the physics of light, how the light interplays with the person you’re lighting, reflectance and ambient light and so forth. You just need to understand that there are a couple of components at work. There is the green screen itself, lighting for that as its own module, lighting for the person or persons who are really our subjects, and stepping back away from it, understanding where they’re going to be placed.
Ill mark [X] here where we’re going to bring our model in and we’re a good 10-, 15-feet away from the backdrop. Why is that important? – It’s very, very important. Understanding where to place a model in relation to a green screen is very important. First of all, you’ll note that we have a nice even light across our green screen. And that’s quite important. And ensuring that we’re not so close that we start to have bleed of green onto the skin. We choose green because it’s a color, frankly, that I’m not wearing, that any actor isn’t wearing.
Our skin tone reveals red. So green screen in many instances has replaced blue screen, especially for a lot of the corporate and tv work. If we have any sort of spill of green onto the face, that reduces the separation. It makes it a harder job for the editor to key out. And consequently, makes for some really unusual edges and creates problems in post.
Key Lighting
It’s very important to recognize that you can think of shooting a green screen as very modular. The green screen itself wants to be its own world, lit independently of the subject. The model will take the same sort of lighting that you want to impart on any other set. But, you really need to think in terms of it being an independent set of light sources from our green screen. The rule of thumb is trying to create as even a light as possible across the green screen, to make it easier for the editor to actually work with it and key in whatever background you’re looking for.
So, we’ll turn these on. So, there’s our left side. You can see. There it is on our way form. Now, we’re just going to head over to the other side and we’ll see how that looks now. As you can see, we have a little bit of a hot spot on the left side. We’ll need to back this light off slightly. The type of lights that we’re using in this instance are Kino Flos. These are single-ended, fluorescent lights, made by Kino Flo. And they do a wonderful job of lighting green screens. They are light emissive, as opposed to being point sources, like a Fresnel or something else.
So, in actual fact, very little needs to be done to them to make them soft enough to create a nice even spread of light across the green screen. And, in fact, we’ve used a gel on one of these lights because to demonstrate lighting a green screen, I’ve used one source which has a blue tube in it and the other source has Tungsten tubes. So, to match the color, so that the editor doesn’t come back and yell at me, we have added a bit of warming gel to the one light to match the other, so that we can say that all things considered, apples to apples, they are the same color lights.
With a Kino Flo, unlike a Fresnel source, the barn doors that are on the outsides of the light can direct the light somewhat. But, because you can picture a Kino Flo as an entire panel of light, it doesn’t direct the source as much as say, a 650 Fresnel would. A small Fresnel light. So, what they do, is they really just shape the light somewhat. So, for our purposes, we want to open those doors pretty wide. Because, really, we want as much as that light to hit the green screen as possible. On both sides, we want to create an even light. We’re not trying to cut any of it off.
So, the only thing I think that really needs to be highlighted, in terms of lighting the green screen, is that when push comes to shove, any light source can be a green screen light source. The rule of thumb is simply that we want to have as soft a key as possible to do a couple of different things. To make it possible for us to key the background evenly, which as you can see is fairly important. As well, we simply want to make sure that any wrinkles, any issues that are in our green screen, as you can see, it’s a piece of green screen fabric, are dealt with by having a nice even light source from different areas around the green screen.
This is particularly important because there are seams and often times there are wrinkles in green screen that you simply don’t have time to remove when you’re on the go. So, we have lit this from both sides and as you can see now, we have a nice, even pattern across the green screen, which has filled in any irregularities in it.
Keep in mind a wash coming across the model but also if you have a two edge setup (lights on each side) that the screen is a subject lit seperate than the model themselves.
https://www.lynda.com/After-Effects-tutorials/Choosing-your-lighting-instruments-green-screen/520239/601115-4.html?srchtrk=index%3a5%0alinktypeid%3a2%0aq%3aparallax%0apage%3a2%0as%3arelevance%0asa%3atrue%0aproducttypeid%3a2