Adjusting exposure - Unreal Engine Tutorial

- [Instructor] Next, we move on to a more daily use type of control that will not only affect the look and feel of our scenes in still shuts if we save any, but will more importantly affect how the user will perceive light as they move on, navigate around the environment. To control these, we'll be taking a look here at the exposure rollout. Now, exposure compensation can be thought of as really a lack of rhythmic adjustment for exposure that gets applied on top of our existing camera settings. Meaning it will only be used if a tone mapper, in our case, the post-process volume, is being used. So when we set this to zero, like so, then no adjustments at all is applied to exposure. If set to minus one, then the scene now becomes two times darker, whilst going further than this and setting a value of minus two makes the scene four times darker, and so it goes. Going the opposite way though, so if we enter a value of one, then everything naturally becomes brighter, specifically two times brighter than zero. And when set at two, it becomes four times brighter. (laughs) You get the idea. Connected to this global adjustment of light perception is the min brightness control. As you might assume, this sets the minimum brightness that the art to exposure will dip to when the user is in dark areas of the level. Values for this setting are best adjusted whilst the player camera is in the darkest lighting situation that can be found in a level, so as to ensure that, well, the user will always have good visibility. Let's adjust our camera then by using the controls to come to one of the dark areas of our scene. Don't forget that we might need to set the exposure compensation option back to zero to find a good spot. Maybe viewing the small office room at the back of the space might be a good idea. Once we have our camera viewing a dark area, let's adjust the value here and see how it affects the viewport. So if the min brightness control value is too small. So for this scene, a setting of 0.0001, well, the image appears too bright. If set too large, so let's say a value of eight, the image appears to be too dark. Now obviously, the values that we will use here depend drastically on the dynamic range of the scene or level that we have built. A value of zero for this level will actually stand us in good stead as we move around the environment. Now, a good point to keep in mind here, of course, is the fact that if the min brightness value is set the same as the max brightness value, then essentially, we will have disabled the auto exposure function. So let's move on to the max brightness then. And this does the opposite of the min setting that we've just looked at. And so is best adjusted whilst standing in the brightest area of a level. So if we move our camera to a bright spot then, maybe by the computers at the other end of the office. And just as before, and set the value to small, so 0.2, well, the image appears too bright. And if too large or roundabout the 22 mark, the image appears a little too dark, unless we are exposing for a shot outside, that is. Now, for this particular scene, a value of around about four would generally work nicely. But in order to show how the next control works, we are going to set this to a value of 20 and then look directly out of the window. Next, we're going to look at a set of controls that are absolutely fantastic for controlling a camera that is moving from one lighting situation to another. And so if that is something that you are going to want to be doing in either a game visualization or cinematic, then these next controls are ones to pay attention to. The first of which is the speed up control. Now, this sets the speed at which the camera performs its switch or adaptation when going from a dark to a bright part of the environment. So if we spin the camera around and face the wall, and then spin back around to look out the window, we can see that the exposure adjusts at a decent speed. If we face the dat would again, though, set this value to 10, and once again, spin around, you will notice this time, the camera very quickly adjusts and allows us to see outside. But as we swing back around again, because of the numerical gap between this control and our speed down setting, well, things look a little odd. So these are controls that we need to be careful with. Pointing the camera to look outside a game, we can take a look at our final control, which is the speed down option. This determines the speed at which the adaptation occurs when going from bright to dark. So setting this to a value of 10 and spinning around shows that we now switch very quickly. As this can look quite odd to a user, let's set the speed up to a value of 4.5 and the speed down to a value of around about two. Also, before moving on, let's set the max brightness option to a value of four. Now, as we move around the level now, we can see that the speed up speed down and the max brightness options are all working in connection with each other to ensure that the viewing experience is hopefully a pleasant one. Now, the perception that a user has of lighting in our environment will be key to selling the space that they are roaming as either a realistic or believable one or a stylized one. Whichever our goal may be with the overall exposure settings helping us make overly dark or overly bright areas of the level comfortably viewable, well, you can really see how important these controls are to the post-processing volume.