So, we've gotten the basics out of the way from Astrophotography 101. You know what gear to pack for your next shot and you've got a cool idea planned out. The weather doesn't totally suck and the sky is clear! The moon is way behind the horizon and you can see the stars perfectly. The next step is to set up your gear and fire away! But how do you go about shooting exactly? Do you expose once for the entire scene? Do you light the foreground artificially? Do separate shots for foreground and sky? Have someone standing in the foreground holding a flashlight up at the sky to signal the mothership while spinning a flaming piece of steel wool in a circle? (please, for the love of God, stop doing this)... Again, there is no "right" or "wrong" way to shoot pictures of the night sky, but there are definitely better ways that will leave you with a cleaner image after your final editing process (yes, you have to edit these...stay tuned for another post on that). Ill go over a few different methods starting with the least complicated and getting gradually intricate.
1.) The Single-Shot-for-the-Entire-Scene method, a.k.a. 'Photography':
Duh. You compose your image the way you want it to look in your viewfinder and do a single exposure for the entire shot. You'll most likely end up with a nicely exposed sky and an underexposed, dark foreground that will look noisy due to the excess of shadows and blacks. You can also use artificial light to give life to your foreground like I did above with the Mrs. We both held headlamps simultaneously for a few seconds during the exposure and it ended up looking like the image above. There's nothing wrong with this kind of shot at all, and if done properly, the simplicity of it will make other methods look overdone. There are a million different ways to do this and they are all a lot of fun. Just don't forget that the galaxy itself is a compositional element and that it plays a big part in how your image comes together.
This is by far the simplest and least complicated way to go about shooting the night sky and 85% of what you see people posting on social media and the internet are these types of shots. When you see timelapses of the night sky, they are basically playing a fast slideshow of hundreds of individually exposed images just like this taken a minute or so apart. The next few methods are a bit more complex and require a lot more work on the back end, but can be a lot more rewarding in terms of image quality. I'll go over the editing process some more later on, this post is really about the image capture portion of the overall equation.
**** Disclaimer: Some will tell you this is the only acceptable way to shoot landscape astrophotography. They are also the most likely to be doing 10 m.p.h. under the speed limit in the passing lane and not allowing anyone else to get by. Try not to forget that this is an art and that you are really just trying to convey your vision through your equipment and that your editing process is just as important as your shoot. Don't impose ridiculous rules upon yourself because you're afraid of what some stuffy purist will have to say about your work. None of this is cheating. Just don't go overboard and start superimposing skies into foregrounds from totally different scenes. Sooner or later, people will figure it out and you'll just look like an asswipe.
2.) Shooting the same scene multiple times for Image Stacking.
This ties in with a specific style of editing called stacking, which basically means you take a bunch of the same image and allow photoshop to blend them together in order to "average out" signal/camera noise and allow the sky to be way clearer in your final image. Again, more on this later. The above picture is the result of about 15 shots being "stacked" and blended in post production. This method is not difficult to do, it just takes a bit longer because you really need at least 10 frames in order for it to work well. To shoot an image that you're going to stack later on, simply take 10-20 shots of the same image back to back and save them for later. Try to do this as quickly as possible because the Milky Way moves across the sky as the planet spins and if you allow it to move too much, it can be difficult to align everything later on. If you do this right, you can get a completely noise-free image which will look a lot more pleasing to the eye and just incredible. Stacking is an essential part of my process and I use it in the vast majority of my shots. It's easy to do and radically improves the quality of the final image. It can be used in conjunction with every other method here and really should be used no matter what unless you're running short on time.
You've probably already figured this one out, especially if you've ever used a cell phone to capture a panoramic image of a wide landscape. You can do the same with your camera's sensor to create extremely high-resolution images with immense amounts of detail! All you really have to do is start at the edge of your scene and move your camera (in portrait orientation) a few degrees at a time from one end to the other taking a properly exposed astro-photo each stop along the way. Make sure each frame has a solid amount of overlap (about a third of the image) with the previous so that you can stitch the images together easily later on. You can have several rows up and down and you can also use stacked frames to keep your noise level low! There are many possibilities and you have lots of creative control as you can use different exposures for the foreground and the sky. I use this method a lot. The above shot had about 20 individual images in it, five frames for the sky, each frame with three stacked exposures. Also, there were five frames for the foreground with one exposure per frame. As your exposures get more complicated, your processing time will increase exponentially. You'll have a good amount of work to do on the back end, but it is worth it as you see your vision come together in a beautiful final product. The above image was being bounced around in my head for over a year before I was able to make it work, mostly because of uncooperative Hawaiian weather!
4.) Bracketed Exposure/HDR/Exposure Blending:
It's a lot to wrap your head around bracketing/HDR at first, but you're not doing anything that is any different from panoramic-stitching or image stacking. Think of this as image stacking of 3 exposures of different levels of bright and dark, or exposure values. Bracketing means taking a correctly exposed image and then adding two extra shots. First: a stop underexposed to capture more detail in the highlights; the second: a stop overexposed to capture more detail in the shadows. All three--when blended together in post-production--will allow the image to capture a wide dynamic range of shadows, highlights, midtones, blacks and whites and is commonly referred to as HDR. Your camera can do exposure bracketing automatically, you just have to activate it. (Read the manual!) Some people like to take this a step further by doing 5, 7 or even 9 bracketed frames to capture maximum sensor data. Many cameras don't really need to do all of that (especially the modern Sony Alpha and Nikon cameras) because their sensors capture a massive amount of data and have around 14-stop dynamic ranges already.
How does this apply to astrophotography? Simple. You capture your foreground first using a 3-shot bracket with lowest possible ISO settings, a higher aperture setting and a longer exposure time. Then for the sky, shoot several frames from the same position (you should be on a tripod!) using proper Astrophotography 101 settings (ISO ~3200, aperture <f/2.8, 10-30s shutter speed) to get what is necessary in order to stack a solid frame of the Milky Way. Bring your files home and get to work on blending, and you're good to go in a few hours! The above image was done this way, using a three-shot bracketed exposure for the foreground with a narrow aperture (I believe f/11) in order to keep the whole scene sharp and in focus. I also used a lower ISO setting to keep the noise to a minimum. I then waited about an hour and captured 15 shots of the Galactic center (which was lined up exactly the way I wanted it to be thanks to PhotoPills) which I stacked in photoshop. Finally, I blended both images together for what you see now. There are many, many, many, many different ways to do this, none right or wrong. I hate to speak using military cliches, but these are all just tools for your toolbox. Different tools do different jobs, and experience is best for knowing which is best. Get out there and practice!
In my next post, I'll cover some of the editing methods that you'll need to know in order to process the shots that this article hopefully taught you how to take. It'll be a bit more in depth and have a lot more visual aids, so bare with me as it will probably take a few days to write it. Thanks for taking the time to read this, I hope you got something out of it!