Shooting a series of star shots for a stack

- In a previous Practicing Photographer, you saw me do the necessary groundwork to come out here to the middle of nowhere to shoot star trails, long-exposure shots of the sky that are gonna give me nice, smearing, streaking stars circling around overhead. With all of that done, I know that I've chosen a good location and that I'm not gonna have a moon and that I've got clear weather. I've actually come out here, and I'm ready to get started. I've found that there's a colony of 14 million frogs nearby, so I'm going to be hearing that the whole time.

I don't think that's actually gonna impact the shot. When we got here, it was actually light, so that's something to think about. Do you want to frame your shot ahead of time when you can still see, or do you want to wrestle with it in total darkness. You can do it either way. Getting a shot set up while it's still light does make things quite a bit easier because you can actually see your viewfinder, or see through your viewfinder and more accurately frame a shot. If you can't get to your location until after dark, or if you've only decided to do this after the sun has gone down, that's okay, there are still some tricks you can do to frame up a good shot even when it's pitch black.

We'll look at those in a future installment of The Practicing Photographer. I've gone ahead and set up my shot. Now, there are a lot of things to consider when you're doing this, and a lot of this, you're only gonna figure out through trial and error. You may need to do a few shots in a location before you get one that you like. But there are a few guidelines you can follow for framing. First is, it's a good idea to have something in the foreground. Just bare sky with streaking stars in it is awfully abstract. It doesn't have that much meaning, and it's not actually that dramatic.

I've framed up a really simply shot. It might be kind of boring, I'm not sure. I've just got a nice, leafless tree in the foreground that I'm imagining streaks behind, so that's gonna give me a subject. The streaking stars themselves work best as a background, not as the subject of the image. I'm talking about in terms of your compositional layout. Find something to lock the viewer's eye, to anchor the viewer's eye, and work the stars around that. Now, if you're really good, and you know exactly where the stars are gonna be streaking.

Maybe you've worked out where the North Star is, and so you know the direction they're gonna be going, and where that swirl's gonna be in the sky, you can use the swirl itself, and the specifics of it as a compositional element. You can say, "Oh, I've got this square barn "over here, that's gonna work well with "the circle of stars that's gonna go around it." That's where you really start getting into the artistry of star trails, is learning how to use those lines to your compositional advantage, and you can do that with a little research. It's really cold out here, and to be honest, I just want to get a shot and see what it looks like, so I'm not going too far in that direction.

Focal length is something to consider. For a given, single exposure, you're gonna have longer trails if you're using a longer focal length. And that's just because you're going to have a little more magnification. As you know, from shooting wide-angle, things that are far away get really small, so on a wider-angle lens, you're going to see shorter streaking. If you don't have much time, or depending on the technique you're gonna use, you may decide that you need a longer lens to get the length of streak that you want. Because of the framing we've got here, I needed a pretty wide-angle lens to get the tree that I wanted and the section of sky that I wanted.

I wanted to be sure that there was only tree, I don't want any horizon. You also, ideally, want a very fast lens, a lens that can open up to a really wide aperture. I've got a lens that can open up to 2.8, so that means that I'm gonna gather a lot more light with my exposure, and that's going to give me much better results. We're gonna talk about the technique that I'm gonna use in a little bit. But for right now, I'm just working on getting my shot set up. The last thing that I might want to consider, and this may sound odd, is white balance.

I'm shooting RAW, so I don't really care, but if you're shooting JPEG, your white balance choice is really gonna impact the color of the sky. Shooting a tungsten white balance is gonna give you a really deep blue sky, if there's still any light in the sky. It's just after sunset, so on a really long exposure, I would be seeing still, a lot of light in the sky. Here's a quick look at what I've framed up, this is just a rough shot that I grabbed just to be able to show you the framing that I've got. I think I'm pretty much ready to go, now I just need to wait for it to get darker.

Okay, it's gotten darker, and dramatically colder, so I'm ready to start this. First thing I need to do is think about focus. Autofocus is not gonna work for focusing on the stars, they're too dim so it's not gonna be able to see anything. I could focus on the tree, and to do that I could just shine a flashlight up into the tree, and autofocus would work fine, there. The problem is, I'm gonna shoot this at f/2.8, and if I do that, my depth-of-field is gonna be so shallow that if I focus on the tree, the stars are gonna be blurry.

I'm not gonna focus on the tree, I'm gonna focus on infinity, and I did that by dialing the focus manually to infinity and then backing off a little bit from it. If you're not clear on how any of this "focusing in low light" stuff works, check out my Night and Low Light class, I go into detail there on how to work in these conditions. As I said, I'm shooting at 2.8, that's gonna give me a whole lot of light gathering all at once. Now, there are two ways that I can go about doing this shot. I could dial in a really long exposure, like an hour-long exposure, and just let it sit here and track the moving stars.

That can work great. The problem is, I face a very particular noise situation, there. I get noise in an image from two different things. From having the ISO up really high, or from long exposure noise. That's what happens when I turn the sensor on and just leave it on for a long time, pixels get stuck on, and they get overloaded, and the image looks noisy. Most cameras, including this one, have a long exposure noise reduction feature that can work really, really well. But still, long exposures are tricky.

The sensor heats up more, which makes it more prone to ISO noise and long exposure noise. Rather than doing a long exposure, I'm going to do a series of short exposures, and then stack those in post-production to create a star trail effect. I've dialed in some manual settings, here. I've gone to 30 seconds on my shutter speed. I've set my ISO at 800. I chose 800 because it's fast enough that I get a lot of good light gathering, but I have practically no noise problem at all on this camera at ISO 800.

I could probably even go to 1600 and be okay, and end up with each frame having even brighter stars on it. I've got ISO 800, I've set my shutter speed to 30 seconds. Now, what I'm gonna do is use the camera's built-in intervalometer to shoot a frame every 30 seconds. It's gonna take a 30 second exposure, and then it's gonna shoot another one. I've turned off long exposure noise reduction so that there's not a big delay after each frame. I think I'm ready to go.

What I'm gonna do is just start that up, and then I'm just gonna let it sit for a while. This camera has a built-in intervalometer. Intervalometer is just something that lets you do time-lapse. If you don't have one, you can use an external intervalometer. There's one other trick you can try, and this varies in effectiveness from camera to camera, and that is to get a remote control that has a lock on it. That is, I can push the shutter button and then lock it somehow, so that the shutter button stays pressed down. I could then put my camera in burst mode.

What may happen on your camera, is every time it finishes a 30 second exposure, it just takes another one right away. Then, I don't have to deal with an intervalometer at all. But again, that varies from camera to camera. In some cases, it varies depending on how your long exposure noise reduction works. If your long exposure noise reduction works in real-time, then you're good. If it requires a period of processing after, that may not work very well. Okay, I've lose track of where the intervalometer is. Interval Timer Shooting, that's what I'm looking for.

Okay, I'm set for 30 seconds. I'm gonna tell it to fire off 100 frames. I may let it do all of those, I may not, I don't know. But I'm gonna start it up here. Here, it just fired the first one. Now it's just gonna sit there and percolate, which means that I can go sit in the car, and try to warm up and wait it out. Once it's done, all I need to do is take the card out and get to processing, and that's where a lot of different things can happen, and I have a good amount of control over what my final image is gonna look like. I'm gonna show you how to do that in a future installment of The Practicing Photographer.