Original subtitles

Hello, and welcome everyone to our next lesson.

So,

last time,

one of the things that I explained is that the sky is one

of the most important light sources that we can use,

and it has a very,

very big impact on on what we get and how our seed will look like.

So this time around,

I want to go into another topic that I would say is actually even more important

than the Skylight because it's something that is incredibly fundamental.

To how we render images and how we perceive the world. Not only as people in real life,

but also as Gamers or digital artists,

And what I would like to talk about now is actually cameras and exposure in

that sense because you remember that earlier in the first lesson, I said that.

Some of the relationships that we work with with digital lighting,

they are actually sort of like arbitrary.

So they they are relative in many ways where we can like the example that I

gave was we can have values that are vastly different from one another,

but we could actually make them look the same and that is a very

interesting and super important concept to understand.

And I also think that Even though it's a little bit like more on the technical side of things,

it is actually something that will make your your work stand out.

If you understand these Concepts and in the beginning,

it might be a little bit more hard to follow through with these ideas or two. You know,

like constantly think about what might be right.

But at some point it will become very natural and you will just sort of like feel what's right to

a certain degree because based on All the experience that you have accumulated

and that's actually something how it works for me, these days.

So like I have a lot of the numbers kind of like, in my brain already. I do know,

a lot of the relationships and I've worked extensively with these systems.

So for me,

it's way more creative now and when I started learning it was a bit

more technical but when you have the technical aspects down,

it actually becomes something. That is incredibly.

Creative.

So let's Jump Right In with that.

And the first thing that I would like to show you and that is very important to understand as

something that I actually found here to serve as a pretty

good illustration here and if I just zoom in a bit

so one of the big problems that exists within the realm of lighting and digital

Work is basically the difference of how the human eye sees light,

and how a camera sees light.

And these things are fundamentally different because the camera is basically just raw data.

And and that is also how our eyes work, like our eyes sample data.

The big problem though is,

is that like we have a brain and our brain does something with that information.

And that is also fairly interesting because when you take photos with, like, a normal camera, like,

you know,

like a DSLR Just like a another like digital camera like a small

camera or like even a camera that uses old school film.

It looks vastly different than what you, for example,

can see on an iPhone because I found actually has some smart software in the back.

That does something so iPhone actually Alters the images when you take them

because what they want is that when you take a picture with an iPhone,

they want that the picture of looks sort of like what you saw And so it matches like the memory

that you have of when you took the pictures like this Sunset it looked so good.

And that is actually because again there is smart Tech behind it.

So it's sort of like a brain in a certain way and the thing is that human

eyes have a higher dynamic range than a camera does.

So like you can see here like a compact camera is

between five and seven stops of dynamic range.

Dslrs can be high Sure.

And then we have the human eye, which is between 10 to 14 stops.

However, we have the brain aspect.

So, here, you can see the image on the left is like,

if you would focus your eyes on the horizon line in the sky,

that is kind of like what you would get.

And if you would like, focus on the foreground, and by the way, these also match,

like what you would get with photography,

right? So like you either like, expose the image for like so that the sky,

Has nice colors at nice values of usually end up with something, dark here and a sunset,

or you like exposed for the foreground and then the back, we'll just like blow out completely.

So the thing is now, our eyes constantly adjust for the different values. And then our brain,

actually creates the image on the right,

which is sort of like very balanced and very natural.

And the problem is that cameras just don't do that.

So,

like when when you work in,

A cinematic way.

Then like you have to make a decision if you like want to work really more, like,

how a camera doesn't work or if you want to work more with like,

how the eye perceives things and we can use these light

units that Mentioned in the Exile and the video before,

where like we can use actual physicalized units.

And then if we use like proper camera, exposure settings and stuff like that,

we actually run into these issues.

And so some games decide to narrow the range and

all these kind of things to bring it more together.

Like for example when you have like a competitive

shooter and you kind of want to be inside,

and See the outside properly or you want to be outside and you want to see the inside properly.

So you can shoot people quickly and make decisions because you have good visibility.

So, these games usually work with like a compressed,

or condensed range and to sort of like illustrate. What that means.

I'm going to Draw Something Beautiful. Again,

as I like imagine,

like,

over here, we have like super pitch-black.

And then over here,

we have like the It is thing that you can imagine and that does

not even have to be like the sunlight. This can be like,

I don't know,

like some weird like Star exploding and space such as

creating the brightest flare that you like ever seen.

So like now the thing is, is that like our human eyes then basically like see,

let's make it like this.

Let's say like on the left, there is like pure black, right?

So let's say like, somewhere over here is Maybe Like a candle.

So candle light is very dark. It's not super bright.

and then,

Let's say over here,

we have bright sunlight.

So our eyes now they can sort of like see

this range really well.

and a camera can sort of like, only see like,

This range really well.

And then what that means is that if we, because like, we can move our camera exposure on this,

like, scale,

if we like, in this range. So we see the candle, nice,

it means that everything that is outside here in this basically part,

it will blow out and become white.

The other way around is if we would expose for this site here so we can see the sunlight nicely.

Everything that is like, for example,

Inside a building over here,

where the candle is it will be almost pitch black. Like we will not see it with the camera,

but since the eyes constantly adjust, and then the brain computes a final image,

the human eye does not necessarily run into this problem.

And this is very, very important to understand.

And again,

like, depending on what type of content you make,

you can shrink these ranges.

So you can basically say like, well, I will only make the Sun. So Right that it's over here.

So then these both fit into the same range and of course

you will create an image that is a bit more flat.

So there is like nothing really that you can do against that if you do that.

But it's like a conscious decision that when you work with camera exposure and

one of the things that I also want to say before we like move on with this,

is that

Nailing your exposure and your value balance is probably one of the most important things when

working with lighting like at all like it's usually when I look at like student work

for example or other other people's work, we're like they're less experienced,

oftentimes I see.

Of course, for example, problems like colors being all over the place. That's,

that's also a very common problem,

but the biggest problem that I usually see is that the values don't feel, right,

that they feel imbalanced,

and they in turn, don't create a super pleasing image. Because like,

it's not always about realism often, it's just really, like, what feels good.

Luckily, though,

there are a bunch of Helpers that can actually help us to nail these things down because like,

first of all,

a lot of this stuff with the photography elements is replicated in game engines engines as well.

So that means that because we look into the virtual world with the camera.

There's a lot of knowledge that is around there in the world,

regarding how cameras work and how people have been taking photographs for like years.

And we can Can leverage that knowledge and that is actually very fun to do.

It's very exciting and also it helps us to create something more like pleasing in that sense.

So here I have a scene which is completely dark right now and if you want to work with this to

right now,

like I chose one of the samples so you can like just go in here samples and scroll down.

And it is the archivist interior that I chose.

There are a few tiny little modifications that I made.

So the project runs on r-tx. So I like turn these things off.

I removed all the lights that were in the scene as well.

So that is something,

you know, just so to be aware of that.

I did a little bit of cleanup here

and now, the first thing that I want to do is I want to start with my sky.

And the way that I do my sky is if I'm using a static Sky,

I always go to the engine content folder. And in case you don't see that you can go to Settings,

and you can go to show engine content.

And then in the surge, I just type sphere.

And somewhere here is the editors fear and we did that in the last session as well.

I use this one because it has the perfect UVS for for what I need.

So this is a good thing and then

I have my sky material again like this.

This is just like the setup that I chose for now.

So,

before we actually apply that quickly, let's make sure.

Excuse me,

that we have all the Shadows turned off here.

Okay, great.

And then we apply this one and suddenly everything goes, boom,

obviously.

So we have like our huge light source in here now and this is one of the

great things with Lumen it's ampuls emissive materials, completely.

So like you do get a lot of lighting from it and I really like this here where it can actually see

how these little pockets of light go through it and also go into like the reflections here.

Giving you some nice soft Reflections from the trees and stuff really Really beautiful.

I like this a lot.

So nevertheless though,

we need to blow this thing up because it's going to be our Sky though.

So I'm going to do fifteen thousand with the scale locked.

And now we actually have this

and now you can see that.

Kind of like not really a lot is happening besides this just blowing out completely,

right?

So now, one of the things that we need to do is we need to sort of find a balance for this,

right?

And there's a bunch of ways that we can do this.

so,

if we look at the texture,

so I would argue, we can apply some exposure bias,

your so I would argue that this is somewhat a

Well maybe like 3:00 or something like it's definitely afternoon like it's

not like midday because you can also like if we see the Shadows,

they're not super long but then again they're also not like 12 oclock Shadows.

So this is potentially like maybe 3:00 so we know. Okay,

this is like early early afternoon here.

So,

let's keep that in mind.

And now,

if I just find my

Window again here.

with the

exposure stuff.

So here is a very interesting thing that you can find

if you search for orders of magnitude luminance.

And this is very,

very interesting because what this basically is is someone went out into nature

and measured the brightness which is here like Candela per square meter or

what is this like

Yeah, it's like I don't actually know if it's like kilo or like whatever.

But so basically these are the CD values so this is like 10,000.

And here we have the small values.

So this is the luminance for a night sky, for example,

which is like incredibly dark.

And here, you can already see what I described before that.

The range has between certain things are incredibly huge.

Alright,

so here, for example, we can see that a white illuminated cloud in like full day.

Time basically is 10,000 Candela per square meter.

Sometimes you will see a value called nits and gnats is sort of like the new value like

or did they like how its name today? Like a lot of like this place and stuff like that.

It used to be Candela per square meter but now they

call it knits but the actual value is there the same.

Like if you calibrate your display to like 120 Candela,

it's the same as like 120 minutes.

So sometimes you just see these different names but like

Candela per square meter in its is this Same thing.

So now we basically have a number here, right?

And one interesting thing as well, is that I told you guys for example,

that

The sunlight in like, super strong daytime, it's it can be like 120,000 Luxe.

It can also be like 85 or 50 thousand depending on cloud coverage, like how the atmosphere is,

there's a lot of factors to this, right?

So like the idea here,

is that we create a pleasing balance between our sky and

our son for a setting that kind of fits this time of day.

Day and there's a bunch of different ways of doing this.

So the first way is to basically start with balancing the sky,

and for that,

I'm going to just fly out and we can see that our Auto exposure is adjusting right now,

because if we go to the Post volume,

We actually have nothing set here. So what you can see here per default,

we are an auto exposure and some people really disliked it.

But I'm going to show you how we can tame this and actually have a do what we want

because I honestly believe that most people that Really struggle with auto exposure.

They don't really know the right tools on how to actually

balance it out in a way that it that it really works.

And I'm also going to explain to you why Auto exposure

is actually a great thing if you can control it correctly.

So for now I'm keeping it like this.

And also you can see that the sky is right now, like the emissive value is so bright.

Ted,

of course,

everything becomes like really black Back but also we don't really have working lighting.

So let's let's consider that too.

But for now so what we want to do is we kind of want to look at

these clouds here and then find a spot where and this is up.

We also like I have to mention there's like some artistic freedom in this because like,

we can't actually because like, this is a photo, right?

Like we don't know what the brightness actually was of these clouds,

but we can sort of like Derive something and be like smart about it so let's do that.

The first thing that we're going to do is we're going to go to show

and then we go to visualize and then we're going to go to HDR.

And this thing here, it might be confusing,

but it's super cool and very important because it helps us a lot with like,

sort of, controlling our exposure, and measuring different values.

And I'm not going to give you guys a break down of this right now.

However,

what I will say is we will look into all of this on the

Fly and we will learn how to use and interpret it.

So right away that you can see here.

Have this little square and these numbers below here,

they actually measure just what's inside that square.

Sadly, I don't know any way to make the square and you bigger.

So like I don't know if that is like a possibility,

somehow to increase the area on where where things get measured.

So

we'll,

we'll have to work with this because like, if you can increase this,

you can get a bigger average of something that you measure.

But then again, so like here we can see the nits which is the same as the Candela per M2 here.

We can see the locks which is a totally different way of calculating this and then

we can also see what EV 100 this is and we'll also going to get more into this.

So if we remember that,

when we look at our

Data here is that, okay,

white, illuminated clout.

So that is like 10,000 and then we also have around 7,000 for the average, clear sky.

So the thing is this,

this is not an average clear sky even though there is some clear

sky but we will probably not really reach that necessarily.

So one thing that I also think it's important is that

this

varies a lot between here and here. So like you can see, this is like an average white cloud.

And we can read here that is like 18,000

And we can also like read over here where we are in 7,000.

So why is that even though they're both white.

So the thing is,

this one here, here's the sun disk.

So this one is incredibly close to the sun,

right? So the values are super, super high,

and if I would just apply some exposure compensation here,

you can see that the values read the same. So the data is always the same, right?

We're just exposing the image differently,

so you can see that this Is still even though I made the whole image darker,

this is still way brighter than this one.

So here we have to make a smart decision of where

are we actually going to pick our like 10,000, right?

And I would argue that, it's not here,

like I think like this is the wrong value here.

I think that this is actually

a more like working value here and we can see where like,

an eight thousand seven thousand nine,

Red,

which means that over here, we're like an 11 12 on this part.

So now what I'm going to say is actually I think that this is good.

I think that's great because the 10,000 is also for like more like a midday.

So in the afternoon it does get slightly darker.

Which means that even though we have a white cloud over here,

you can see that we are more like on for.

5,000.

And that means that we will not reach this like super, super high, daytime intensity,

because that's not what it is anymore.

It is an afternoon.

So we will not have the same intensities as we would have on a midday and that will also reflect

in how much power we will give to the sunlight if we would like to change this, however,

like if we would say,

like okay

this let's make this midday right?

So we would probably go like to somewhere like here where we can see like okay White Cloud,

perfect, but we're only on 4000 and the way to change this is to actually open our Sky material.

And then we just crank the intensity and some people might look at this value and say like

that is that is a huge number that feels very unintuitive and initially, I would say like yeah,

I agree,

but this is one of the important things to understand

when you work with more physicalized values,

the values can be very large because that's really how it is in real life, too.

So, don't be afraid of large values. It's going to be Lately fine.

It's going to be no problem with this.

So, let's assume you want to hit something different here.

So,

I'm just gonna go like with 5,000

And we can see,

we're on 6000. So maybe let's, let's, let's go like nuts. Let's do 12,000.

And that was way too much.

So let's go with 8,000

And now we are on.

Is that 10,000?

Is that a zero? Yeah, that's a zero.

Okay, so now we're on 10,900. So let's go with 7500.

Okay,

so now we have the sky balanced out and you can see it looks exactly the same as before,

and that is because our Auto exposure is constantly,

trying to adjust to an overall pleasing value for this image.

So now it gets brighter because I'm looking at it dark tree and

now it gets darker because I'm looking at the bright Sun.

So like the auto exposure is constantly following along and the actual

value that I'm ciosing here right now doesn't really matter.

So this would be what you could choose if you would then want to like go for a stronger

contrast between the Sun and the sky but I'm going to go back to my 2,500 here

and you can see it got darker of horse and now the exposure adjusts again.

So I'm going to say hey I'm actually quite happy with being it around here with these values.

So here we have like the 11,000 in this At 10,000 here.

We have like five thousand because again midday so I'm kind of happy with this. All right.

So now what we can do is we like or let's do the first thing actually. Let's go to our skylight.

And actually capture this data because right now you can see we don't really have any lighting.

So I'm just going to go to visualize for now turn this off

and the Skylight even though it is set to movable,

it doesn't automatically capture these textured changes.

And if we turn on real-time capture,

it does not work with this guy like this because real-time capture is built

for the atmospheric system for constantly updating the skyline.

What we need to do, when we like, altered these values to actually see what has been happening,

we need to old-school. Go down here and hit recapture.

And now you can see we have something

and what you can also see is it kind of like some of these

colors start like matching up with what we see here.

So if we look at the shadow side here and we look at this shed outside,

we're actually starting to get some values that seem like a rather close which is

a really nice this thing and now you can see the thing that I was saying before,

like the inside is completely dark but Ever since I have Auto exposure, turned on.

What happens if we go in here?

So now it actually starts exposing for this.

I will get some really nice stuff and this might be a little bit crazy which is

why again we need to sort of tell the auto exposure what to do as well.

Because right now it might be overdoing it and we also get this and one quick thing

that I'm going to do is because I actually changed the bloom settings so let's

Revert. This.

And it is very intense.

So we can either change the intensity,

or what we actually should do is we should change the threshold

because the threshold is not meant for values. This High,

the threshold here is actually set for non-physical values.

So what we need to do is you see, even eight doesn't do it.

So, what happens if I do 5,000?

So now we can see since we're using physical value.

Use,

we need to tell it to not bloom like crazy with this incredibly high value that we have from the

sky right now and per default. Again, these values are tweaked for non-physical values,

so I'm just going to try and find something that works here,

and I think,

We could actually do maybe like 20,000.

oops,

so we get a little bit of Bloom still

Let's do any team

but yeah that's secondary for now so we can see.

Now we have this kind of like working and there's like

some lighting in sight but again it is not yet beautiful.

So this is the first step of getting something to work and I think

this is kind of like a really nice way of setting it up.

So we're going to close off with this lesson here and

in the next lesson we're going to bring in the sun,

we gonna start actually Getting the exposure and I'm going to show you a few tricks of

how to balance these things out. So thank you so much for watching and see you