Hi everybody welcome to another episode of Exploring Photography right here on AdoramaTV brought to you by Adorama, the camera store that has everything for photographers. I’m Mark Wallace and I’m hanging out here in Kampuchea Party Republic studio and I have this amazing infinity wall right here. It’s a white background. You might have something like this in your studio, maybe you have a white roll of seamless and this video is all about working with this big white beast. How do you control that? How do you get it to go from white to gray to black? The reason I’m making this video is because so many people have seen me take photos on a wall just like this and the wall goes to complete black or a really dark gray and I get emails almost every day saying how is that happening? Well that’s what we’re going to talk about in this video and we’re going to end with a really amazing portrait, so let’s get started right now. Alright well now we have a light and we have a model. This is Kongka and so what we’re going to be doing is I’m going to just first show you, that we have a light, a model and our big white background but when I take a photo at this distance, right here so look right into my lens. Beautiful! What the heck? The background is absolutely dark so what is going on back there? Well to understand that, we need to break this down step by step. We need to first understand what we can do with the ambient light because with their eyes we see a white background but on the picture it doesn’t show up. So what’s going on? We have to control the ambient light, then we have to understand something called the inverse-square law. So we’re going to do that really quickly and simply then we’re going to put everything together to control that background, to create a really beautiful portrait so I’m really excited. Let’s get started. To understand what’s happening with our white background we first need to understand a very important principle of flash photography and that is when you add a flash to your photo you actually have two exposures, you have the ambient light, that’s light from the Sun or light in the room like these fluorescent lights and you have the light from the flash and you can control those two things independent of each other. So the first thing we need to do to control our big white background is to control the ambient light. So let me illustrate this. So I have my flash turned totally off. I don’t have a trigger on my camera. I have my camera set to f/9 aperture priority mode and I’ve increased the ISO to ISO 800 just for this illustration, so let me show you what will happen here if I take a picture just with the ambient light, so we’re going to look right in the lens Kongka looks great. BAM!so I take that that’s at 1/60th of a second it’s a really not a very good picture because we don’t have any flash but you can clearly see that the camera can see that white background and it shows up crystal clear. We don’t want that, we want to eliminate that and the simplest way to do that is just to underexpose the background, so what I’m going to do is I’m going to change my camera to ISO 200. That’s my base ISO for this camera and then I’m going to speed up the shutter speed so from I think it was the 1/7th of a second something like that. I’m going to go to my camera’s sync speed that’s the fastest speed that my camera can use, the fastest shutter speed that my camera can use with the flash. Now if you don’t know about sync speed fear not. I actually have a bunch of videos about sync speed and I have link to those in the description of this video so if that’s a new concept for you just watch those videos and it’ll all make sense. So now I have my camera at f/9 at sync speed 1/180 of a second and at ISO 200 now let’s take that same a picture again, so you’re going to look right at me same exact thing, click, it’s totally black, there’s nothing there look it’s just blank and so what we’ve done is we have eliminated the ambient light. There is nothing that is showing up on that white background except the light that comes from our flash and that means now that we can control everything the only thing that’s going to show up on that background is the light that comes from this flash or other flashes and so we can do some really groovy things but now what we need to understand is what happens when we move this closer and farther away from our subject and to the wall and how can we make that brighter and dimmer so we’re going to do that next. Now that we know how to control the ambient light we need a quick refresher on the inverse square law. Now if the inverse square law is confusing to you don’t worry, I’ve already made a video in depth about this but let’s just have a refresher. What happens with the inverse square law is it’s the law that illustrates how the power of the light falls off from the source and so it comes out really strong right here and then it just has a little cliff wow it gets much, much less powerful and then it just sort of evens out as it goes along and so we have this really strong light and then it drops off and then it evens out back here and that has a lot of implications for us when we’re shooting with a white wall, and so Kongka, you’re going to come right back out and we’re going to illustrate this and so here’s what we’re going to do. So we’re going to start with you close to this light. I’m going to turn this guy on and we’re going to shoot with model close to our light. Now remember the light is falling off rapidly, so that means that the light is much more powerful here than it is back here which means that she’s going to be exposed properly but the white background is going to be underexposed making that darker and her perfectly illuminated. So I’m going to meter this and so we’ll do that. I hope this meter should meter right about f/8 so we’ll do that and it’s exactly f/8 ISO 200 f/8 and I’m a shooting at sync speed which is 1/180 of a second. Look right in my lens, beautiful, so we’re going take this shot and it looks just like it did before. We have that dark grey background. Now watch what happens remember this light is falling off, with an evening out so we’re going to have you come back here much closer to the backdrop. Remember the light now is evened out and so the backdrop, the white background and Kongka are both going to be exposed about the same so I’m going to meter this again because we don’t have as much power as we did before, so I’ll meter this. That meters at f/3.6, so I’m going to adjust my aperture accordingly and we’re going to take a photo, beautiful I love that right there and look now we have a perfectly exposed model and a nice white background. That’s what the inverse law does for us, so if you want a dark background, you got to make sure that your light and your model are close together. If you want a nice white background make sure that your light is farther away and that your model and your white background are closer so that, that inverse-square law works for you. Alright we know how to expose the ambient light so that we have a black background. We know how to use the inverse square law to control the different shades of gray that we have on our background let’s put that all together and make a really nice portrait Kongka is out here she has a nice white top and black pants and that is going to be nice and contrasty with the background. We’re going to let that fall into darkness, now to do this I want soft light, so we’re starting with our fill light. This is this giant 7′ silver umbrella that’s just going to sort of shower down light. It’s going to bounce off the white floor and fill in but we want nice directional light as well and so we have this small softbox and that is going to come from the side and make sure we have fall-off and so that’s going to sculpt her cheeks and give us some directional soft light now because these are so far from the background Kongka’s white top is going to contrast with this dark background, it’s going to fall into darkness not completely into darkness, we just want a dark gray but that is exactly how it’s going to work out. We’re going to shoot this outfit and maybe a couple of different wardrobe changes and I’m going to show you the results, so let’s get started right now I love these images, I think they’re soft and wonderful. Thank you so much Kongka Chan and you know what she won Cambodia’s Next Top Model and if you want to see all of our amazing pictures and behind-the-scenes stuff here is her Instagram so you can make sure you check that out. I want to tell you about two other videos that I’ve made, about white backgrounds. I did one called white paper tricks that will show you how to sculpt really interesting things on a white background using some of the principles that I taught today and I also want to remind you about the inverse square law video that is a deep dive into the inverse square law, if that’s a little bit confusing to you. I have provided links to both of those videos in the description of this video and a link to her Instagram account in this video and so thank you so much. How do you say thank you in Camia? អរគុណ orgoon thank you. Don’t forget to subscribe and we will see you again next time.