Using infrared filters - Photoshop Tutorial

Our eyes see the world, of course, in visible light, but there are other kinds of light. There's ultraviolet light. There's also infrared light. If you have an infrared filter on your lens, you can photograph the world in infrared light which yields a very different result than normal visible light. Most infrared photographs are black and white, although it is possible to do color infrared. And typically, what you get is a dramatic change in vegetation, sometimes in skies, and it's possibly, maybe you can get a difference in skin tone. But doing infrared portraits with a digital camera is actually somewhat difficult, and we'll look at why. Sitting in front of the image sensor of your camera, there is a filter that serves a lot of functions. And one of the things it does is it cuts out infrared light. So, by default, your digital camera is not necessarily super sensitive to infrared light. You can get an idea for how sensitive it is by putting the camera in bold mode, opening the shutter, and shining like your TV remote, or something else that's infrared. If you see the little light bulb at the end light up, then your camera is able to perceive infrared. You also need a filter to go on your lens, and there are a lot of different kinds of filters. The most popular is the Kodak Wratten 87 series of filters. There are different variations with different densities. Which one is right depends partly on the look you're going through, going for, and partly on the infrared sensitivity of your camera. The problem is these filters are very expensive, particularly if you need a large filter size. And some cameras are more sensitive to infrared light than others. So, before you commit to this idea, before you go out and buy the pricey filter, you really ought to do some searches on the web for your specific camera model, and infrared to find out what people are saying about your camera's infrared sensitivity. If you see indications that your camera is a good candidate for infrared shooting, then by all means go ahead and get yourself a filter and find yourself some subject matter that seems like it will lend itself to infrared shooting. We're here in the Conservatory of Flowers in San Francisco, and I've got behind me some palm trees that are in nice direct sunlight. Different kinds of vegetation responds differently to infrared, vegetation usually turns white. I know palm trees do a good job. It also helps to really have some direct sunlight on them, which we've got here. So I've framed up a shot, and I've done this just like I would frame up any shot. I'm going to show you what I've got. I don't have an infrared filter on the camera right now. I have simply set my camera to aperture priority. I'm at f/11 because I want to ensure some deep depth of field. And if I take this, so here's what we get. It's not the most captivating image. It's a simple still life made out of some palm trees, but once we get into infrared, it's going to become much more interesting. Now, to get it into infrared, I need to get my infrared filter on the front of the lens. But before I do that, there are some things to consider. This infrared filter is extremely dense. It's going to cut 8 to 10 stops of exposure from my scene. That means my viewfinder is going to be useless once I put this filter in, I'm not going to be able to see through it, and neither is the autofocus system in my camera. It's going to go blind because it's basically just going to be looking into dark. So, I need to make sure that my image is composed and focused before I put the filter on. It's already composed. I haven't changed anything since I took the last shot. It's also still focused because I haven't changed anything. However, if your shutter button is your autofocus button, then when you go to press the shutter button to take your next shot, the camera is going to refocus. If your focus points end up focusing on the sky, your image is going to go out of focus. So you have a few options. One, if your camera allows it, you can take autofocus off of the shutter button, for example, I have my camera set up so that this button back here auto focuses, so I can press the shutter button without worrying about it refocusing. Another thing you can do though is once the image is focused, simply switch your camera from autofocus to manual focus. Now, the autofocus mechanism is disabled, so my focus is locked in. So I've got my shot composed, I've got it focused. I can't tell anything about exposure until I get the filter on. So I'm going to do that next. So I'm taking the filter, and I'm just screwing it onto the front of the lens. I'm being kind of careful for two reasons, I don't want to change my shot. I don't want to bump the camera such that it will move around and recompose my shot because once these are on there, I can't see, so I would have to take them off and start all over. Also, these are 77 millimeters filters, 77 millimeters in diameter. They're big enough that screwing them on straight can be a little complicated. So, I'm trying to be careful with that, because if I get them screwed on crooked, they're going to be very difficult to remove. So I am framed, I am focused, I have the infrared filter on. On my particular camera, metering at this point is useless. The camera is going to meter completely incorrectly. If I hit my metering button, it's telling me f/11 at an eighth of a second. If I take this picture, it's just going to be black. So, the meter has gotten it totally wrong. I have to go to a completely manual mode here. I'm going to switch my shooting mode over to manual. Now, when I took this shot before, I shot it at f/11 to try to guarantee deep depth of field. I could continue to do that except that it's going to require a very, very long shutter speed. Let me show you what I mean. I'm going to dial in to 8 seconds just because from experience, I know that an infrared image at ISO 3200, which is where I am at right now is going to need at least 8 seconds. So I'm going to take that shot and see what happens. But as I watch during these 8 seconds, I realize that the trees are blowing around. That might be kind of cool looking. All right. First of all, it's a little bit dark. I am going to go up another stop. So I'm going to go to 15 seconds which is going to brighten things up a little bit. Your histogram is critical at this point when you're feeling around for your exposure because it's going to tell you whether you've actually got things bright enough or not. So, I'm going to do this 15-second exposure. The tree branches are going to be very, very blurry. I might decide I like that. I think in this case, I want some of them to be as sharp as possible. So I'm just checking my exposure here. This looks pretty good. I think 15 seconds is right at f/11. But it also means that the tree branches, as you can see, here are pretty smeary. I actually like the look, but I'd also like to try it with tree branches that aren't quite so over rot with motion blur. So I'm going to open my aperture up some. I'm at 15 seconds right now at f/11. If I go to f/8, that will get me down to roughly 8 seconds. So let's try that. I'll set that to 8, and this down to f/8. I could go down another stop. I'm going to go down to f/5.6. That will get me down to 4 seconds. So let's see what that looks like. I'm going to take the shot. Now, on my camera, I know that ISO 3200 is a useable ISO. It doesn't yield an image that's too noisy. Yours may not be capable of shooting so fast, or it might be able to go faster. If you can go faster, that's great. You can use even quicker shutter speeds, but if you have to go to a lower ISO, then your shutter speeds are going to get longer. I like this better. The branches are not as smeary, and I think the exposure is good. Let me check the Histogram one more time. That looks right. So, I think this is the shot. I might bracket it a little bit. So by bracket it, I mean shoot it with a couple of different exposures. I think I'll go to a longer one. I'm going to go up half a stop to six seconds. A stop, of course is a doubling. If I'm at four seconds, I can go up half a stop by going to six, leaving my aperture the same. I don't really want to go any wider because I like to keep the depth of field I have. That's giving me some nice stuff. These images all look really red, because I'm shooting through a red filter. This is not my final image. There's still lot of processing that has to be done, and we'll look at that in the next movie. This is the infrared shooting process. It is obviously a handful. There's a lot you have to do here. You've got to have the special filter. Also, you can only shoot with very long shutter speeds there. I'm in bright daylight here. There's no situation where my shutter speed is going to go down below 4 or 5 seconds. That makes it troublesome for shooting landscapes because things blow around, makes it hard to do portraits because it's hard for people to hold still for that long. If you're really in to infrared, and you would like a more capable infrared digital camera, you can have your camera altered. You can have that filter that sits in front of the image sensor removed, and you'll find that your shutter speeds go way up, your infrareds go much faster. Your infrared sensitivity increases a lot, but it permanently alters your camera. Without that filter, you can see some variety of different artifacts when you're shooting normally. You might see weird moire patterns, you might see weird color shifts. So, when you do this alteration, you are really permanently changing your camera to an infrared camera. So if you've got an old SLR that you're not using, this might be a fun thing to play with. Again, do some Internet searches, and you will find companies that will modify your camera for infrared shooting. So, the next step to finish the image is to get it into the image editor, do our black and white conversion, and see what we can do by way of playing with the tones in the image.